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EXTRACT  FROM  TABLE  OF  CONTENTS. 

PART  II. 


Chapter  I. 

The  Building  and  Finishing  Woods  of  the  United  States. — Their  char- 
acteristics, properties  and  uses. 

Chapter  II. 

Wood  Framing — Ordinary  Construction. — Framing  timber — Framing  of 
wooden  buildings — Framing  of  floors,  supports  for  partitions,  roof  construc- 
tion— Superintendence. 

Chapter  III. 

Sheathing,  Windows  and  Outside  Door  Frames. — Sheathing  of  walls  and 
roof — Cellar  frames — Types  of  windows,  construction  of  window  frames  in 
frame  and  brick  walls,  patent  windows,  casement  windows,  pivoted  windows, 
bay  windows — Sash,  store  fronts — Glass  and  glazing — Outside  door  frames. 

Chapter  IV.  * 

Outside  Finish,  Gutters,  Shingle  Roofs. — Eaves  and  gable  finish,  gutters  and 
conductors  —  Siding  —  Porches  —  Dormers — Shingling,  flashing — Wood  sky- 
lights. 

Chapter  V. 

Furring,  Inside  Finish,  Doors,  Stairs. — Furring  for  finish  and  plastermg — 
Grounds  and  corner  beads — Flooring — Doors  and  door  frames — Casing  of 
doors  and  windows — Paneling,  beams,  columns,  stairs. 

Chapter  VI. 

Builders'  Hardware, — Heavy  hardware,  bolts,  nails,  screws — Finishing  hard- 
ware, butts,  locks,  knobs,  bolts,  window  trimmings,  trimmings  for  blinds  and 
shutters 

Chapter  VII. 

Heavy  Framing. — Framing  of  posts  and  girders,  bracing,  mill  floors — Compound 
and  trussed  girders — Suspended  floors,  galleries. 

Chapter  VIIL 

Specifications. — Carpenters'  work — Joiners*  Work — Hardware. 

Appendix.  * 

Tables  of  Strength  of  wood  and  cast  iron  columns,  wooden  beams,  maximum  spaa 
for  floor  joists. 


PART  III. 

TRUSSED  ROOFS  AND  ROOF  TRUSSES. 

(IN  PREPARATION) 
TABLE  OF  CONTENTS. 

INTRODUCTION. 

Chapter  I. 

Types  of  Wooden  Trusses  and  the  Mechanical  Principles  involved. 

Chapter  II. 

Types  of  Steel  Trusses. 

Chapter  III. 

Lay  Out  of  Trussed  Roofs— Bracing  of  the  Roof  and  Trusses. 

Chapter  IV.  » 
Open  Timber  Roofs  and  Church  Roofs. 

Chapter  V. 

Vaulted  and  Domed  Ceilings ;  Octagonal  and  Domed  Roofs. 

Chapter  VI. 

Coliseums,  Armories,  Train  Sheds,  Exposition  Buildings,  etc. 

Chapter  VII. 

Computing  the  Purlin  and  Truss  Loads  and  Supporting  Forces,. 
ii 

Chapter  VIII. 
Stress  Diagrams  and  Vertical  Loads. 


BUILDING  CONSTRUCTION 


AND  SUPERINTENDENCE. 


BY 

F.  E.  KIDDER,  C.  E.,  Ph.D., 

ARCHITECT. 

Fellow  of  the  American  Institute  of  Architects. 
Author  of  "  The  Architect's  and  Builder's  Pocket-Book.** 


REVISED  AND  ENLARGED 

BY 

THOMAS  NOLAN,  M.  S.,  A.  M., 

Fellow  of  the  American  Institute  of  Architects, 
Assistant  Professor  of  Architecture,  University  of  Pennsylvania, 


Part  I. 

NINTH  EDITION, 
REVISED. 

MASONS'  WORK. 

Illustrations. 


WILLIAM'  T.  COy^^^i)CK. 
,  23  Warren  Street. 


Copyright  by 
F.   E.  KIDDER 
1896,   1897,   1898,   1900,   1902.   1903.  ^905, 

Copyright  by 
KATHERINE  E.  KIDDER 
1906,  1909. 


Composition:  S.  L.  PARSONS  &  Co. ,JNC^,  Nfiv  Vark 
Presswirk  :  BdU  ■  Ir  r'AI^'kl'in  '<?{!.CSS',  'NeVv'  <YQ'k 
Binding;    THGMAS  ;Rfc5s^^.^.i,  4: -S^jK."  Net/  Voik 


PREFACE  TO  FIRST  EDITION. 


THE  primary  object  of  the  author  in  preparing  this  volume  has  been  ta 
present  to  the  student,  architect  and  builder  a  text-book  and  guide 
to  the  materials  used  in  architectural  masonry  and  the  most  approved 
i^ethods  of  doing  the  various  kinds  of  work,  and  incidentally  to  point  out 
gome  of  the  ways  in  which  such  work  should  not  be  done,  and  the  too  fre- 
quent methods  of  slighting  the  work.  That  there  is  a  demand  for  such  a. 
work  has  been  evidenced  to  the  author  by  numerous  inquiries  from  archi- 
tects and  instructors  in  our  architectural  schools,  and  also  by  the  fact  that 
there  exists  no  similar  work  describing  American  methods  and  materials. 

In  describing  methods  of  construction  the  author  has  drawn  largely  from 
his  own  observation  and  experience  as  a  practising  and  consulting  architect, 
in  both  the  Eastern  and  Western  States,  although  much  assistance  has  been 
obtained  from  prominent  architects,  who  have  cheerfully  aided  him  by  their 
advice  and  experience,  and  from  the  various  books  and  publications  to  which 
references  are  made  in  the  text;  to  all  such  the  author  gratefully  acknowl- 
edges his  indebtedness. 

To  make  the  book  convenient  for  practical  use  and  ready  reference,  the 
various  subjects  have  been  paragraphed  and  numbered  in  bold-face  type,  and 
numerous  cross  references  are  made  throughout  the  book.  The  table  of 
contents  shows  the  general  scope  of  the  book,  the  running  title  assisting  in 
finding  the  various  parts,  and  a  very  full  index  makes  everything  in  the 
book  easy  of  access,  ^he  general  character  of  the  work  is  descriptive,  and 
hence  rules  and  formulae  for  strength  and  stability  have,  except  in  a  few 
cases,  been  omitted;  such  data  being  already  fully  presented  in  the  author's 
"Pocket-Book"  and  other  similar  works. 

While  intended  principally  as  a  book  of  instruction,  there  is  much  in  the 
book  that  will  be  found  valuable  for  reference,  and  of  assistance  in  designing 
and  laying  out  masonwork,  preparing  the  specifications,  and  in  superin- 
tending the  constructipn  of  the  building,  so  that  the  author  hopes  that  even 
the  experienced  architect  will  find  it  of  assistance  in  his  work. 

The  enterprising  builder,  also,  who  wishes  to  thoroughly  understand  the 
materials  with  which  he  has  to  deal,  and  the  way  in  which  they  should  be 
used,  will  find  in  this  book  much  information  that  cannot  be  readily  obtained 
elsewhere. 

To  make  the  description  as  clear  as  possible  many  illustrations  (mosfiy 
from  original  drawings)  have  been  inserted,  and  an  endeavor  has  been  made 
to  present  only  practical  methods,  and  to  favor  only  such  materials  as  have 
been  found  suitable  for  the  purpose  for  which  they  are  recommended. 

F.  E.  KIDDER. 

Denver,  Colo.,  June  i,  1896. 

iii 


PREFACE  TO  REVISED  EDITION. 


IN  offering  this  new  edition  of  "Building  Construction  and  Superintendence, 
Part  I,  Masons'  Work,"  to  the  pubhc,  the  author  of  the  revision  has 
constantly  borne  in  mind  the  original  purpose  of  the  book  as  set  forth 
by  Mr.  Kidder  in  the  preface  to  the  first  edition.  He  has  endeavored  to 
bring  it  down  to  the  present  day  in  such  form  that  it  will  continue  to  hold 
a  high  place  as  one  of  the  standards  of  the  best  contemporary  practice  in 
the  elements  of  architectural  masonry  construction  and  superintendence. 
While  he  has  endeavored  to  explain  the  principles  of  the  subject  in  a  way 
that  may  be  readily  understood  and  followed  by  all  who  are  in  any  way 
connected  with  or  interested  in  building  operations,  whether  architects, 
engineers,  contractors,  students,  artisans  or  the  general  public,  he  has,  at  the 
same  time,  tried  to  set  forth  these  principles  and  methods  of  procedure  in  a 
scientific  manner,  preserving  and  further  strengthening  the  purpose  of  the 
work,  not  only  as  a  hand-book  for  professional  and  commercial  use  and 
reference,  but  also  as  a  text-book  for  schools  and  colleges.  He  must  leave 
it  to  those  who  use  the  revised  work  to  decide  the  measure  of  his  success. 

It  was  Mr.  Kidder's  intention  to  publish  a  thoroughly  revised  edition, 
and  shortly  before  his  death  he  expressed  the  wish  that  the  writer  under- 
take the  work.  The  labor  put  upon  it  has  been  lightened  by  the  memories 
of  a  friendship  lasting  through  many  years. 

The  work  has  been  congenial,  those  divisions  of  the  theory  and  practice 
of  architecture  which  include  building  construction  and  superintendence 
having  been  the  subjects  of  special  study  on  the  part  of  the  writer  for  many 
years.  It  embodies  notes  made  and  conclusions  arrived  at  in  the  design, 
construction  and  superintendence  of  different  types  of  buildings  during  a 
practice  of  many  years  and  includes  also  notes  made  in  special  study  and 
research  in  connection  with  courses  of  lectures  given  in  the  School  of 
Architecture  of  the  University  of  Pennsylvania  on  the  theory  of  and  prac- 
tical procedure  in  architectural  construction.  Much  time,  labor  and  thought 
have  been  required  for  the  preparation  of  the  revision  and  it  is  hoped  that 
the  usefulness  of  the  book  will  be  greatly  increased. 

Four  years  ago,  in  writing  the  preface  to  a  late  edition  of  another  of 
his  works  and  in  comparing  that  edition  with  the  preceding  one,  Mr.  Kidder 
said :  "At  that  time  the  author  thought  he  had  covered  all  those  practical 
details  relating  to  the  planning  and  construction  of  buildings,  with  which 
the  architect  was  concerned,  tolerably  well,  and  it  would  appear  as  though 
the  publishers  of  the  book  thought  so,  too ;  but  as  the  years  have  come  and 
gone,  so  many  and  such  great  improvements  have  taken  place  in  the  building 
world,  so  many  articles  invented,  new  methods  of  construction  developed, 
and  higher  standards  established,  that  the  present  edition  is  perhaps  not 
■more  complete  for  the  times  than  was  the  first  edition." 


V 


PREFACE   TO  REVISED  EDITION, 


This  may  be  said  of  the  present  edition  as  related  to  the  preceding, 
edition  of  "Building  Construction  and  Superintendence,  Masons'  Work." 

The  new  edition  includes,  in  general,  a  careful  examination  of  every 
article  in  the  book  and  a  revision  of  every  one  in  which  changes,  omissions 
or  additions  of  data  or  methods  of  procedure  are  deemed  necessary  or 
advisable;  the  omission  of  some  articles  and  the  addition  of  many  new  ones; 
the  rewriting  of  some  chapters  and  the  addition  of  one  entirely  new 
chapter;  the  addition  of  nearly  four  hundred  new  illustrative  constructive 
drawings;  the  addition  of  many  new  tables  and  formulas;  the  classification. 
of  the  subdivisions  of  each  chapter;  the  addition  of  titles  to  every  article 
and  illustration ;  the  addition  of  new  footnotes  referring  to  many  authorities 
for  further  data;  and  a  new  and  comprehensive  index  with  very  numerous 
cross  references. 

In  Chapter  II,  "Foundations  on  Compressible  Soils,"  the  subject  of 
"Caisson  Foundation  Construction"  has  new  examples  taken  from  recent 
noted  buildings,  and  the  general  principles  of  "Heavy  Cantilever  Foundation 
Construction"  are  explained  and  illustrated. 

Chapter  III,  "Masonry  Footings  and  Foundation  Walls,  Shoring  and 
Underpinning,"  has,  among  other  additions,  new  articles  relating  to  "Recent 
Examples  of  Heavy  Needling  and  Underpinning." 

Chapter  IV,  "Limes,  Cements  and  Mortars,"  is  rearranged,  enlarged  and 
entirely  rewritten.  The  subdivision  dealing  with  concretes  is  taken  out 
and  treated  in  Chapter  X,  "Concrete  and  Reinforced  Concrete  Construction." 
The  great  and  ever-increasing  importance  of  the  subject  matter  of  this, 
part  of  the  subject,  and  the  vast  amount  of  new  and  useful  data  resulting  from 
recent  experiments  and  tests,  led  the  writer  to  widen  largely  the  scope  of 
this  chapter. 

Chapter  V,  "Building  Stones,"  is  virtually  rewritten.  There  are  seven 
new  tables.  The  revision  includes  much  new  matter  relating  to  the  "Pro- 
duction and  Value  of  Dififerent  Kinds  of  Building  Stones,"  the  "Distribution 
of  Building  Stones  in  the  United  States,"  the  "Minerals  of  Building  Stones" 
and  the  "Classification  of  Rocks  Used  for  Construction  Purposes,"  and 
additional  lists,  containing  a  very  large  number  of  examples  of  new  buildings 
in  which  the  different  kinds  of  stone  have  been  used,  are  added. 

Chapter  VII,  "Bricks  and  Brickwork,"  is  carefully  revised  in  accordance 
with  much  new  data.  Included  in  the  new  matter  of  the  text  and  illustra- 
tions may  be  mentioned  especially  "Sand-lime  Bricks,"  "Surface  Patterns 
in  Brickwork"  and  "Brick-veneer  Construction." 

Chapter  VIII,  "Architectural  Terra-cotta,"  is  entirely  rewritten,  enlarged 
and  illustrated  with  many  new  figures.  Special  attention  is  given  to  the 
subjects  of  "Composition  and  Manufacture,"  "Surface  Treatment"  and 
"Polychrome  Terra-cotta;"  and  there  are  numerous  examples  of  architec- 
tural construction  taken  from  recent  prominent  buildings. 

Chapter  IX,  "Fire-proofing  of  Buildings,"  is  entirely  rewritten,  very 
much  enlarged  and  illustrated  with  two  hundred  figures. 

Chapter  X,  "Concrete  and  Reinforced  Concrete  Construction,"  is  a  new 
chapter  with  over  one  hundred  illustrative  drawings.  The  marked  increase 
in  the  use  of  concrete  in  all  kinds  of  buildings  and  the  rapid  development 


PREFACE   rO  REVISED  EDITION. 


vii 


of  reinforced  concrete  construction  make  the  subject  matter  of  this  chapter 
of  great  relative  importance,  and  it  is  treated  as  fully  as  the  limits  of  the 
book  permit.  The  third  division  deals  with  ''Reinforced  Concrete  Construc- 
tion." The  subdivision,  "General  Theory  and  Design,"  includes  a  brief  out- 
line of  the  principles  of  the  mechanics  of  materials  leading  to  the  theory  of 
flexure  of  reinforced  concrete  beams,  girders  and  slabs  and  to  the  theory  of 
reinforced  concrete  columns,  and  is  purposely  made  to  agree  with  the  gen- 
eral presentation  of  the  subject  in  the  revised  chapters  of  Mr.  Kidder's 
hand-books,  so  that  these  books  may  be  conveniently  used  together.  Useful 
working  formulas  and  tables  are  introduced  in  conformity  with  Mr.  Kidder's 
custom  as  exemplified  in  the  several  chapters  of  preceding  editions  of  this 
work.  The  fourth  division  of  the  chapter  deals  with  "Concrete  Block  Con- 
struction" and  includes  a  discussion  of  the  different  types  of  blocks,  the 
composition  of  the  materials  used,  the  processes  of  manufacture  and  the 
details  of  building  construction. 

In  Chapter  XII,  "Lathing  and  Plastering,"  the  matter  dealing  with 
"Hard  Wall  Plasters"  is  rewritten,  and  made  to  conform  as  closely  as  pos- 
sible to  the  facts  and  to  the  conditions  prevailing  at  the  present  time. 

Chapter  XIII,  "Specifications,"  is  revised  and  enlarged  with  many  new 
pages  of  text.  Several  new  specifications  have  been  inserted,  for  cements,, 
concrete  blocks,  etc.,  and  complete  specifications  for  the  reinforced  concrete 
work  of  a  recently  erected  building  are  added. 

The  Appendix  is  rearranged  and  greatly  enlarged  by  the  addition  of 
many  tables.  Addendas  of  recent  valuable  data  relating  to  the  "Weight,. 
Crushing  Strength  and  Ratio  of  Absorption  of  Building  Stones"  and  of 
''Lists  of  Recently  Erected  Stone  Buildings"  are  inserted  and  tables  giving 
recent  data  concerning  the  "Building  Stone  Industry  in  the  Different  States" 
and  giving  the  "Comparative  Characteristics  of  the  Different  Slates"  are 
added.  Ten  new  tables  containing  data  relating  to  cements  are  added,  deal- 
ing with  the  "Geographical  Distribution  of  Cements,"  the  "Production  of 
Cements,"  the  "Development  of  the  Cement  Industry,"  the  "Imports  and 
Exports  of  Cements,"  the  "Total  Consumption  of  Cements,"  etc.  New 
tables  relating  to  clay  products  used  in  building  operations  are  added,  giving 
the  "Products  of  Clay  in  the  United  States"  during  the  past  decade  and 
the  "Value  of  Clay  Products."  Tables  are  added,  also,  showing  the  extent 
of  "Building  Operations  in  the  United  States"  and  the  "Character  of  the 
Buildings  Erected." 

Throughout  the  entire  revision  the  writer  has  taken  great  pains,  to  fur- 
nish reliable  data.  Wherever  possible,  references  to  the  sources  of  informa- 
tion are  given,  either  in  the  text  or  in  the  footnotes.  To  all  who  have 
assisted  him  in  any  way  the  writer  acknowledges  his  indebtedness,  and 
expresses  his  thanks. 

The  names  and  addresses  of  manufacturers  and  dealers  in  materials  and 
appliances  used  in  masonry  construction  are  given  when  necessary,  and  any 
possible  advertising  resulting  from  the  insertion  of  any  name  is  entirely 
accidental  and  incidental  to  the  purposes  of  the  book. 

The  author  of  the  revision  requests  that  readers  will  kindly  call  his  atten- 


Yin 


PREFACE   TO  REVISED  EDITION. 


tion  to  any  typographical  or  other  errors,  in  order  that  they  may  be  corrected 
before  the  next  edition  goes  to  press. 

He  desires  to  acknowledge  his  indebtedness  to  Mrs.  F.  E.  Kidder  for 
many  valuable  suggestions  relating  to  the  revision,  and  to  the  publisher 
who  has  done  everythfng  possible  to  cooperate  in  the  efforts  made  to 
increase  the  usefulness  of  the  work. 

THOMAS  NOLAN. 

Philadelphia,  Pa. 
February,  1909. 


TABLE  OF  CONTENTS. 


Introduction  XVII 

Requirements    for    the    Successful    Practice    of  Architecture. 
Superintendence  of  Building  Construction. 

CHAPTER  I. 

Foundations  on  Firm  Soils   i 

Staking  Out  the  Building.  Foundations — light  buildings — nature 
of  soils,  bearing  power  of  soils,  examples  of  actual  loads,  meth- 
ods of  testing.  Designing  the  Foundations,  proportioning  the 
footings,  examples,  center  of  pressure  to  coincide  with  center 
of  base,  footings  at  different  levels.  Superintendence. 

CHAPTER  II. 

Foundations!  on  Compressible  Soils   25 

Pile  Foundations — classes  of  wooden  piles,  kinds  of  wood,  point- 
ing and  ringing,  manner  of  driving,  bearing  power,  loads  on 
piles,  cutting  off  and  capping.  Grillage  capping.  Concrete  Piles  * 
— wooden  piles,  concrete  piers  and  concrete  piles  compared — 
different  types — manner  of  sinking  or  driving — reinforced  con- 
crete piles — Compressol  system — cost  of  concrete  piles.  Spread 
Foundations.  Reinforced  Concrete  Footings — general  design — 
formulas  for  calculating  strength — examples.  Steel  Beam  Foot- 
ings— methods  of  calculating — formulas  for  strength — examples. 
Steel  Beam  Footings — methods  of  calculating — formulas  for 
strength — examples — tables  for  safe  loads— combined-  beani 
grillage  footings — base-plates.  Timber  footings,  calculations  for 
size  of  timbers — foundations  for  temporary  buildings.  Masonry 
Wells — general  description,  with  examples.  Caissons — Caisson 
Foundation  Construction — general  description — different  types 
manner  of  sinking — examples.  Cantilever  Foundation  Construc- 
tion— general  description — examples. 

CHAPTER  III. 

Masonry  Footings  and  Foundation  Walls.     Shoring  and  Under- 
pinning   87 

Masonry  Footings — concrete  footings,  stone  footings,  offsets, 
brick  footings.  Inverted  Arches,  calculations  for.  Foundation 
Walls — bonding,  filling  of  voids,  thickness  of  walls.  Retaining- 
walls — design  and  construction.  Area  Walls.  Vault  Walls. 
Superintendence  of  Foundation  Work.    Dampness  in  Foundation 

ix 


X 


TABLE  OF  CONTENTS. 


Walls — damp-proofing  and  water-proofing.  Window  and  En- 
trance Areas.  Pavement  Vaults.  Pavements  and  sidewalks. 
Curbing.    Shoring,  Needling,  Underpinning  and  Bracing. 

CHAPTER  IV. 
Thomas  Nolan. 

Limes,  Cements  and  Mortars    

Common  Limes — chemical  properties,  slaking  and  mixing.  Sand. 
White  and  Colored  Mortars.  Setting  of  Lime  Mortar.  Durability. 
Hydraulic  Limes — general  description  and  chemical  properties. 
Non-staining  Cements.  Natural  Cements — :cIassification,  defini- 
tions, use,  distribution,  chemical  analysis,  characteristic  prop- 
erties and  requirements,  strength  tests,  specifications,  miscel- 
laneous data  and  memoranda.  Choice  of  Cements  and  Selection 
of  Brands.  Portland  Cements — classification,  definitions,  his- 
tory, use,  production,  chemical  analysis,  manufacture,  character- 
istic properties  and  requirements,  strength  tests,  specifications, 
miscellaneous  data  and  memoranda.  Puzzolan  Cements.  Strength 
Tests  for  All  Cements.  Cement  Mortars — uses,  mixing,  propor- 
tions of  sand,  cement-lime  mortars,  grout,  data  for  estimates, 
strength,  water-proof  mortar,  effect  of  temperature.  Mortar 
Colors  and  Stains — classifications  of  colors  and  materials  used, 
^  mixing. 

CHAPTER  V. 

Building  Stones    

Building  Stones  in  General — production  and  value,  distribution, 
minerals  of  building  stones,  rock  classifications,  geological 
record.  Granite — general  characteristics,  descriptions  of  impor- 
tant granites,  classified  by  States,  counties  and  districts.  Lime- 
stone— general  characteristics,  classified  descriptions.  Marble — 
general  characteristics,  production,  classified  descriptions.  Onyx 
IVIarble.  Sandstone — general  characteristics,  production,  classi- 
fied descriptions.  Slate — general  description,  uses,  physical 
properties,  production,  classification,  classified  descriptions.  Mis- 
cellaneous Building  Stones — lava  stone,  blue  shale,  trap,  soap- 
stone.  Selection  of  Building  Stones — eff^ects  of  climate,  tem- 
perature and  atmospheric  action;  durability,  finishing,  setting, 
color,  strength,  fire-resistance  and  cost.  Testing  of  Building 
Stones.  Seasoning.  Protection  and  Preservation  of  Stonework. 
Artificial  and  Manufactured  Stone. 

CHAPTER  VL 

Cut-stonework   

Classes  of  Cut-stonework,  Rubble-work,  ashlar.  Stone-cutting 
and  Finishing — tools,  kinds  of  finish.  Trimmings,  relieving  and 
supporting  lintels,  sills,  arches,  label-moldings,  relieving-beams 
over  arches,  elliptical  arches,  three-centered  and  four-centered 


4 


TABLE  OF  CONTENTS.  xi 

arches,  pointed  arches,  flat  arches,  rubble  arches.  Centers.  Mis- 
cellaneous Trimmings — entablatures,  columns,  copings,  stone 
steps  and  stairs.  Bond  Stones  and  Templates.  Treatment  of 
Cut-stonework  in  the  Wall — laying  out  ashlar,  joints,  backing, 
bonding,  setting,  protecting,  pointing,  cleaning  down.  Slip 
Joints.  Strength  of  Cut-stonework — columns,  lintels.  Measure- 
ment of  Cut-stonework.  Cost  of  Cut-stonework.  Superintend- 
ence of  Cut-stonework. 

CHAPTER  VII. 

Bricks   and   Brickwork   311 

Bricks — composition,  manufacture;  glazed,  enamelled,  paving  and 
fire-bricks.  Classes  of  Building  Bricks — common  bricks,  pressed 
bricks.  Color,  size  and  weight  of  bricks.  Requisites  of  good 
bricks — strength.  Sand-lime  Bricks.  Cement  Bricks.  Brick- 
work— thickness  of  mortar  joints,  laying  bricks,  wetting  bricks, 
laying  in  freezing  weather.  Ornamental  Brickwork — belt-courses, 
cornices,  surface  patterns.  Construction  of  Brick  Walls — bond, 
anchoring  walls,  corbelling  for  floor  joists,  bonding  at  angles, 
openings,  joining  new  to  old  walls.  Thickness  of  Walls — party- 
walls,  curtain-walls.  Wood  in  Walls — cracks  in  walls.  Damp- 
proof  Courses.  Hollow  Walls — methods  of  construction,  bond- 
ing. Brick  Veneer  Construction.  Details — brick  arches,  vaults, 
chimneys,  fireplaces,  mantels,  stairs,  brick  nogging.  Cleaning 
Down  —  efflorescence  —  damp-proofing.  Crushing  Strength  of 
Brickwork.    Measurement  of  Brickwork.  Superintendence. 

CHAPTER  VIII. 
Thomas  Nolan. 

Architectural  Terra-cotta   405 

Composition  and  Manufacture.  Surface  Treatment.  Color.  Uses. 
Durability.  Inspection.  Laying  Out  Terra-cotta.  Comparison 
of  Bad  and  Good  Methods  of  Terra-cotta  Construction.  Setting 
and  Pointing.  Time  Required  to  Make  Terra-cotta.  Cost. 
Weight.  Strength.  Protection.  Examples  of  Terra-cotta 
Construction — cornices,  pediments,  balustrades,  balconies,  domes, 
vaulted  ceilings,  facings  for  reinforced  concrete,  light-courts. 
Fire-resistance  of  Terra-cotta. 

CHAPTER  IX. 
Thomas  Nolan. 

Fire-proofing  of  Buildings   435 

General    principles     of     Fire-proofing  —  definitions.  Limiting 
Heights   and   Areas   of   Non-fire-proof  buildings.     Materials — 
stone,  brick,  tiling,  terra-cotta,  mortar,  plaster,  concrete,  cast- 
iron,  wrought-iron,   steel.     Construction.     Column-protection —  . 
.tile,  concrete,  lath-and-plaster — plaster-block,  concrete-block  and 


xii 


TABLE  OF  CONTENTS. 


composition-block — pipes  and  column  coverings.  Fire-proof 
floors,  standard  tests,  steel  framing  for  fire-proof  floors.  Brick 
floor  arches.  Tile  floor  arches — setting,  protection  from  stains 
and  weather,  floor  and  ceiling  finish,  segmental  arches,  flat  arches, 
side,  end  and  side-and-end  construction,  tile  lintel  construction, 
reinforced  tile  flat  arch  systems,  Guastavino  vault  and  dome  con- 
struction. Concrete  Floor  Arches — composition  of  the  concrete, 
different  forms  and  methods  of  reinforcement.  Segmental  Con- 
crete Floor  Arches — Roebling  system,  Rapp  system,  White  sys- 
tem. Flat  systems.  Reinforced — Columbian,  Roebling,  Berger, 
Ferroinclave,  White.  Expanded-metal,  lock-woven  fabric,  steel 
wire  or  mesh  reinforcements.  Merrick  System.  Sectional  Con- 
crete Floor  Construction — hollow  concrete  I-arches.  Thatcher 
unit  system.  Beam  and  Girder  Protection — tile  coverings,  con- 
crete coverings.  Fire-proof  Flooring.  Fire-proof  Roofs  and 
Roof-coverings.  Fire-proof  Suspended  Ceilings.  Fire-proof  Par- 
titions— different  types,  brick  partitions,  concrete  partitions,  plas- 
ter-block and  wall-board  partitions,  tile  partitions,  reinforced  tile 
partitions,  "Phoenix"  partition,  "New  York"  partition,  metal- 
and-plaster  partitions.  Berger  studs,  rib-studs,  "all-united"  steel 
studs,  solid  studless  metal-and-plaster  partitions.  Classification 
of  Metal  Laths — detailed  descriptions.  Fire-proof  Furring — tile 
and  hollow  brick  furring,  metal  furring,  furring  for  architectural 
forms.  Fire-proof  Interior  Finish.  Fire-proof  Stairs.  Miscel- 
laneous Fire-proof  Devices.  Fire-proof  Dwelling  Construction. 
Earthquake-resisting  Construction  for  Fire-proof  Buildings.  Re- 
leased Wall  Facing — Pelton's  system. 

CHAPTER  X. 
Thomas  Nolan. 

Concrete  and  Reinforced  Concrete  Construction   

Concretes — early  and  recent  uses,  proportions,  mixing  and  plac- 
ing of  materials,  strength  and  elastic  properties,  resistance  to 
action  of  cold,  heat  and  sea-water,  cost,  weight,  miscellaneous 
data,  recent  examples,  specifications.  Mass  Concrete  Cons-truc- 
tion — early  examples,  molds  and  forms  with  details,  foundations 
and  cellar  walls  with  constructive  details,  rammers  and  puddlers, 
cost.  Reinforced  Concrete  Construction — definitions,  history, 
early  uses  and  examples.  Beams  and  Girders — theory  and  de- 
sign, properties  of  the  materials,  stresses.  Notes  on  the  flexure 
of  beams,  manner  of  failure,  formulas  for  rectangular  beams,  T- 
beams  and  slabs,  working  stresses,  bending  moments,  amount 
and  disposition  of  reinforcement,  diagonal  tension,  compression 
rods,  adhesion  of  steel  to  concrete.  Columns — design,  strength, 
longitudinal  reinforcements  with  examples,  wrapped  or  hooped 
reinforcements.  Materials  of  Reinforced  Concrete  Construction 
— concretes,     cements,    aggregates,     proportions,  consistency,. 


TABLE  OF  CONTENTS. 


xiii 


strength  and  elastic  properties,  general  qualities  and  properties 
of  the  steel.  Types  of  Reinforcements — classification,  plain  and 
deformed  bars,  truss  and  stirrup  attachments,  unit-frame  systems. 
Column  and  Pier  Reinforcements — examples.  Types  and  Sys- 
tems of  Reinforced  Concrete  Construction — classification,  mill- 
construction,  skeleton  construction,  American  system,  Colum- 
bian system,  Cummings  system,  Johnson  bar  system,  expanded- 
metal  and  round  bar  system,  Faber  system,  Gabriel  system,  Hen- 
nebique  system,  Kahn  bar  systems,  Merrick  system.  Mushroom 
system,  "M"  system,  concrete  and  structural  steel  systems, 
Visintini  systern.  Protection  of  Reinforced  Concrete  Construc- 
tion— protection  against  fire  and  corrosion.  Erection  of  Rein- 
forced Concrete  Construction.  Cement  and  Concrete  Block  Con- 
struction— history,  uses,  nature  and  proportions  of  materials, 
mixing,  shapes  and  types  of  blocks,  processes  used  in  concrete 
block  manufacture,  facing  and  ornamentation  machines  and 
molds,  details  of  building  construction,  building  regulations. 

CHAPTER  XI. 

Iron  and  Steel  Supports  for  Masonwork — Skeleton  Construction   747 

Girders  and  Lintels — cast-iron  lintels,  cast-iron  arch-girders. 
Supports  for  Bay  Windows.  Wall  Supports  in  Skeleton  Con- 
struction— spandrel  supports,  steel  lintel  supports,  steel  supports 
for  cornices,  bay-window  supports  in  skeleton  construction,  wall 
columns.  Miscellaneous  Ironyvork — bearing  plates,  skewbacks, 
shutter-eyes,  door  guards,  chimney  caps,  chimney  ladders,  coal- 
hole covers  and  frames. 

CHAPTER  XII. 

Lathing  and  Plastering     772; 

Lathing — wooden  lath,  sheathing  lath,  metal  lath,  wall-boards 
and  plaster-boards,  where  metal  laths  should  be  used.  Interior 
Plastering — lime  plaster,  hand-mixing,  and  machine-mixing,  pro- 
portions of  materials.  Putting  on  the  Plaster — descriptions  of 
different  coats  of  plaster.  Hard  Wall  plasters — natural  cement 
plasters,  chemical  or  patented  plasters,  nature  of,  advantages  in 
using,  how  used  and  sold.  Interior  stuccowork.  Keene's  Ce- 
ment. Scagliola — imitation  marble.  Fibrous  Plaster.  Car- 
ton-Pierre. Exterior  plastering — rough-cast,  exterior  stucco- 
work,  staff.  Whitewashing.  Lathing  and  plastering  in  Fire- 
proof Construction — frames  in  metal-lath  and  plaster  partitions. 
Measuring  '  Plasterwork.  Quantities  of  Materials.  Cost.  Colored 
Sand  Finish.    Superintendence  of  Lathing  and  Plastering. 

CHAPTER  XIII. 

Specifications   813; 

General  Considerations.  General  Conditions.  Excavating  and 
grading.     Wooden   Piling.     Concrete    Footings.     Stonework — 


xiv 


TABLE  OF  CONTENTS. 


footings,  foundation  walls,  external  stone  walls.  Cut-stonework. 
Brickwork.  Laying  Masonry  in  Freezing  Weather.  Fire- 
proofing.  Architectural  Terra-cotta.  Lathing  and  Plastering — 
ordinary  work,  lathing,  plastering,  hard  wall  plasterwork,  wire 
lathing  with  metal  furring,  stiffened  wire  lathing,  metal  lath  on 
ironwork.  Solid  Partitions — metal  lath  and  studding.  Roebling 
Concrete  Floor  Arches.  Natural  Cements.  Portland  Cements. 
Reinforced  Concrete  Work — complete  specifications  for  building 
recently  erected.  Concrete  Building  Blocks — rules  and  regula- 
tions governing  the  use  and  manufacture  of  hollow  concrete 
building  blocks,  specifications  governing  the  method  of  testing 
hollow  blocks. 

Appendix  A  

Table  A. — Production  of  Natural  Cement  in  1904,  1905  and  1906, 
by  States. 

Table  B. — Geographical  Distribution  of  the  Portland  Cement 
Industry  in  1905  and  1906 

Table  C. — Production  of  Portland  Cement  in  the  United  States 
in  1904-1906,  by  States. 

Table  D. — Development  of  the  Portland  Cement  Industry  in  the 
United  States  since  1890. 

Table  E. — Production  of  Slag  Cement  in  the  United  States  in 
1904- 1906,  by  States. 

Table  F. — Imports  of  Hydraulic  Cements  into  the  United  States 
in  1903-1906,  by  Countries. 

Table  G. — Comparison  of  Production  of  Portland  and  Natural- 
rock  Cement  in  the  United  States,  with  Imports 
for    Consumption    of    Hydraulic    Cement,  1901-1906. 

Table  H. — Comparison  of  Domestic  Production  of  Portland 
Cement  with  Consumption  of  Portland  and  All 
Imported  Hydraulic  Cements,  1891,  1904,  1905  and 
1906. 

Table  I. — Exports  of  Hydraulic  Cement,  1900-1906. 

Table  J. — Total  Consumption  of  Hydraulic  Cements  in  1906. 

Table  K. — Value  of  Various  Kinds  of  Stone  Produced  in  1905 

and  1906,  by  States  and  Territories. 
Table   L. — Rank  of  States   and  Territories   in   1905  and  1906, 

According   to   Value   of   Production   of   Stone  and 

Percentage  of  Total  Stone  Produced  by  Each  State 

and  Territory. 

Table  M. — Weight,  Crushing  Strength  and  Ratio  of  Absorption 

of  Various  Building  Stones. 
Addenda   for  Table   M. — Weight,   Crushing   Strength,  Specific 

Gravity,  and  Ratio  of  Absorption  of  Various  Building 

Stones. 

Table  N. — Chemical  Composition  of  Various  Biitlding  Stones. 


TABLE  OF  CONTENTS. 


XV 


Table  O. — List  of  Important  Stone  Buildings  in  the  United 
States. 

Addenda  for  Table  O. — Additional  List  of  Important  Stone 
Buildings  in  the  United  States. 

Table  P. — Effect  of  Heat  on  Various  Building  Stones. 

Table  Q. — Comparative  Characteristics  of  Various  Slates. 

Additional  Data  to  Accompany  Table  Q,  Including  Two  Classifica- 
tions of  States. 

Table   R. — Building  Operations  in  the   Leading   Cities   of  the 

United  States  in  1905  and  1906. 
Table  S. — Character  of  Buildings  Erected  in  the  Leading  Cities 

of  the  United  States  in  1906. 
Table  T. — Value  of  the  Products  of  Clay  in  the  United  States 

in  1905  and  1906,  with  Increase  or  Decrease. 
Table  U. — Products  of  Clay  in  the  United  States,  1897-1906,  by 

Varieties. 

Table  V. — Actual  Crushing  Strength  of  Brick  Piers. 
Table  W. — Safe  Working  Loads  for  Masonry. 
Table  X. — Thickness   of  Walls   for  the   Dwelling-house  Class 
of  Building. 

Table  Y. — Thickness  of  Walls  for  the  Warehouse  Class  of 
Buildings. 

Appendix  B   912 

The  White  System  of  Fire-proofing, 


INTRODUCTION. 


THE  successful  practice  of  architecture  requires  not  only  ability  to  draw 
and  design,  but  also  a  thorough  knowledge  of  building  construction  in 
all  its  branches;  at  least  in  so  far  as  to  know  hozv  the  work  should 
be  done,  and  for  conscientious  and  painstaking  supervision  of  the  work. 

Without  a  knowledge  of  the  best  methods  of  performing  building  opera- 
tions, and  of  the  materials  that  should  be  used,  it  is  impossible  for  the  archi- 
tect to  prepare  his  specifications  intelligently,  and  so  as  to  secure  the  kind! 
of  work  he  wishes  done.  Upon  the  thoroughness  with  which  the  specifications 
are  prepared  depends  in  a  great  measure  the  satisfactory  execution  of  the 
work. 

The  position  occupied  by  the  architect  as  a  judge  or  referee  between  the 
owner  and  contractor  also  makes  it  necessary  that  he  should  be  able  to  show 
such  thorough  familiarity  with  common  practice  as  will  command  the  re- 
spect of  both.  Workmen  soon  discover  whether  the  superintendent  is  familiar 
with  the  difference  between  good  and  bad  work,  and  if  they  find  him  wanting' 
they  are  quite  sure  to  take  advantage  of  his  lack  of  knowledge. 

After  the  plans  and  specifications  have  been  prepared  with  the  utmost 
care,  accidents,  failures  and  bad  work  are  quite  sure  to  occur  unless  the  build- 
ing operations  are  carefully  and  intelligently  supervised.  In  fact,  probably 
more  failures  in  buildings  occur  from  the  use  of  poor  materials  and  bad  work- 
manship than  from  faults  in  the  plans. 

While  it  is  impossible  for  one  to  acquire  a  thorough  knowledge  of 
building  construction  from  books  alone,  it  is  necessary,  for  the  young  archi- 
tect especially,  to  depend  upon  technical  books  to  a  large  extent  for  his  knowl- 
edge of  how  work  should  be  done,  and  of  what  materials  are  best  suited  for 
certain  purposes,  and  how  they  should  be  used.  As  a  substitute  for  his  lack 
of  knowledge,  he  must  rely  largely  upon  knowledge  gained  through  the  ex- 
perience of  others,  oftentimes  at  great  cost. 

In  these  books  the  author  has  endeavored  to  describe  all  the  ordinary 
building  operations  in  such  a  way  that  they  may  be  easily  understood,  to 
point  out  the  defects  often  met  with  in  building  materials  and  construction, 
and  to  indicate  in  a  measure  how  they  may  be  avoided. 

To  get  along  well  with  contractors  and  workmen  the  architect  must  feel 
sure  that  his  opinions  and  decisions  are  correct,  and  stick  to  them.  Of  course 
one  can  often  learn  much  from  practical  builders,  but  unless  he  is  already 
somewhat  informed  upon  the  subject  he  is  often  likely  to  be  imposed  upon. 
In  fact,  one  of  the  greatest  troubles  of  young  architects  in  superintending  their 
buildings  lies  in  the  persistence  with  which  builders  and  workmen  will  insist, 
often  to  the  owner,  that  such  and  such  methods  or  materials  are  the  best  for 
the  purpose,  or  th^  the  work  should  be  done  in  such  and  such  a  way,  or 


xvii 


xviii 


INTRODUCTION. 


that  this  or  that  requirement  is  unnecessary  and  not  called  for  by  older  archi- 
tects. Oftentimes  these  assertions  are  deliberate  misrepresentations,  made  to 
5ave  expense  or  labor,  and  unless  the  architect  is  well  posted  on  the  subject, 
and  can  quote  good  authorities  for  his  views,  it  is  difficult  to  combat  them. 

"The  best  workmen  dislike  to  pull  down  or  change  what  is  already  done, 
and  if  inadvertence  or  temporary  convenience  has  led  them  into  palpable 
violation  of  the  specifications,  they  will  often  stretch  the  truth  considerably  in 
their  explanation  and  excuse." 

In  pursuing  his  examinations  of  the  work  it  i«  important  that  the 
architect  or  superintendent  shall  have  a  systematic  plan,  that  all  the  in- 
numerable points  of  construction  shall  receive  attention  at  the  proper  time, 
and  before  they  are  covered  up  or  built  over  so  as  to  make  changes  incon- 
venient or  impossible.  If  the  superintendent  is  not  also  the  architect,  he 
should,  before  the  work  is  commenced,  carefully  study  the  plans  and  specifi- 
cations and  make  himself  thoroughly  familiar  with  all  the  points  of  construc- 
tion, so  that  no  important  feature  will  be  overlooked.  He  should  carefully 
examine  and  verify  all  figures,  to  see  that  no  mistakes  have  been  made  before 
the  work  progresses  too  far. 

In  making  periodical  visits  to  the  building  he  should  go  all  over  the 
building  and  examine  closely  all  work  that  has  been  done  since  his  last  visit. 
Wherever  *a  man  has  been  at  work  he  should  go  and  see  what  has  been  done. 
It  is  only  in  this  way  that  the  superintendent  can  insure  against  concealed 
defects  or  poor  materials.  When  he  is  superintending  several  buildings  at 
the  same  time,  he  should  read  the  specifications  and  examine  the  plans  fre- 
quently, to  refresh  his  memory,  otherwise  he  may  overlook  some  features 
that  cannot  be  as  well  attended  to  afterward. 

Another  important  point  in  efficient  supervision  is,  after  inspecting  the 
materials  delivered,  to  make  sure  that  those  rejected  are  removed  from  the 
building,  and  not  used  during  his  absence.  All  defective  materials  should 
be  marked  in  some  way,  on  their  face,  so  that  they  cannot  be  used  without 
the  mark  showing,  should  the  material  be  incorporated  in  the  building.  The 
superintendent  should  also  insist  that  work  which  has  been  improperly  done 
shall  be  taken  down  at  once,  and,  if  necessary,  take  it  down  or  remove  it 
himself.  Any  mistakes  or  bad  work  that  are  discovered  should  also  be 
pointed  out  or  condemned  at  the  time,  before  they  are  driven  out  of  the  mind 
by  other  matters. 

It  is  very  essential  that  the  superintendent  shall,  at  the  start,  insist  on 
having  the  work  done  as  specified,  and  be  very  careful  to  reject  all  unfit 
material,  for  if  the  contractor  finds  him  lenient  at  the  start  he  will  be  sure 
to  take  advantage  of  it,  and  slight  the  work  more  and  more.  If,  on  the 
other  hand,  he  finds-  that  the  work  must  be  done  right,  or  else  rebuilt,  he 
will  be  careful  to  do  the  work  in  such  a  way  that  it  will  not  have  to  be  done 
over  again.  A  great  fault  with  many  superintendents  is  that  they  do  not  feeF 
sufficient  confidence  in  their  own  judgment  and  have  not  the  courage  to 
insist  on  their  directions  being  followed. 

In  describing  the  different  building  operations  the  author  has  endeavored 
to  call  attention  to  the  points  that  particularly  need  to  te  inspected,  and  to 


INTRODUCTION. 


XIX 


some  of  the  ways  in  which  defective  materials  or  construction  are  covered 
up.  There  are,  the  author  is  glad  to  say,  many  honest  builders,  who  do  not 
countenance  bad  workmanship,  but  the  temptation  to  save  money,'  especially 
when  the  work  is  taken  at  a  low  figure,  is  so  great  that  the  architect  should 
consider  that  his  duty  to  his  client  and  to  himself  is  not  fulfilled  until  he 
has  satisfied  himself  by  careful  inspection  that  the  work  is  being  done  in  the 
manner  specified.  Even  when  the  contractor  does  not  wish  to  slight  the 
work,  there  are,  unfortunately,  many  workmen  who  seem  to  prefer  to  do  a 
poor  job  rather  than  a  good  one,  and  who,  rather  than  lift  a  heavy  stone, 
will  break  it  in  two,  or  save  themselves  all  the  labor  possible,  so  long  as  their 
work  will  pass  unnoticed. 

For  such  the  only  treatment  is  to  require  a  strict  observance  of  the 
specifications  and  the  superintendent's  directions,  with  the  certain  penalty  for 
violation  of  having  to  do  their  work  over  again. 


1 


Chapter  I. 

Foundations  on  Firm  Soils 


I.    STAKING  OUT  THE  BUILDING. 

I.  BATTER-BOARDS,  BENCH-MARKS,  LINES,  ETC.-- 
Except  for  city  blocks,  staking  out  the  building  is  generally  left  to 
the  contractor,  but  the  superintendent  should  see  that  it  is  carefully 
done,  and  very  often  he  is  expected  or  called  upon  to  assist  in  run- 
ning the  lines.  The  principal  corners  of  the  building  should  first  be 
carefully  located  by  small  stakes  driven  into  the  ground,  with  a  nail 
or  tack  marking  the  exact  intersection  of  the  lines.  The  lines  should 
then  be  marked  on  batter-boards,  put  up  as  shown  in  Fig,  i.  Three 


large  stakes,  two  by  four  inches,  or  four  by  four  inches,  are  firmly 
driven  or  set  in  the  ground  at  each  corner  and  from  six  to  ten  feet 
from  the  line  of  the  building,  according  to  the  nature  of  the  ground. 


2 


BUILDING  CONSTRUCTION. 


(Ch.  I> 


and  fence-boards  are  nailed  horizontally  from  the  corner  posts  to- 
each  of  the  other  two  posts,  as  illustrated  in  Fig.  2.  These  boards, 
should  be  long  enough  to  allow  both  the  inside  and  outside  lines  of 
the  foundation  walls  to  be  marked  on  them.  The  stakes  should  also 
be  braced  from  the  bottom  of  each  corner  stake  to  the  top  of  each 
of  the  others.  This  makes  a  firm  support  for  the  lines  and  one  that 
need  not  be  moved  until  the  walls  are  up  and  ready  for  the  first  floor 


Fig.  2.    Stakes  and  Fence-Boards.  Fig.  3.    Different  Lines  Indicated  by  Saw 

Marks,   Nails   and  Notches. 


joists.  These  boards  have  the  great  advantage  over  single  stakes 
of  being  more  permanent,  and  of  allowing  all  projections  of  the 
walls,  such  as  footings,  basement  wall  and  first  story  wall,  to  be 
readily  marked  on  them.  It  is  a  good  idea  to  indicate  the  ashlar  line 
by  a  saw  mark,  the  basement  line  by  a  nail  and  the  footings  by  a 
notch,  as  shown  in  Fig.  3.  In  this  way  no  mistake  can  be  made  by 
the  workmen.  If  the  tops  of  all  the  horizontal  boards  are  kept  on 
a  level,  it  assists  a  great  deal  in  getting  levels  for  the  excavating,, 
etc.  ^ 

The  superintendent  will  be  expected  to  furnish  the  contractor  with 
a  bench-mark,  from  which  he  can  get  the  level  for  his  footings,  floor 
joists,  etc.  This  mark  should  be  put  on  some  permanent  object, 
where  it  can  be  referred  to  after  the  first  floor  joists  are  set  in  place. 
In  giving  such  data  to  the  contractor  the  superintendent  must  be 
very  careful,  as  he  can  be  held  responsible  for  any  loss  resulting 
from  errors  which  he  may  make.  It  is  a  very  safe  and  good  rule  to 
give  as  few  lines,  data  or  measurements  as  possible  to  contractors,, 
requiring  them  to  lay  out  all  the.  work  themselves  and  to  be  alone 
responsible  for  the  accuracy  of  their  work. 


FOUNDATIONS.    LIGHT  BUILDINGS. 


3 


2.  LOT  LINES,  ETC. — For  buildings  which  are  built  out  to 
the  street  line,  the  lines  of  the  lot  should  be  given  by  a  surveyor 
employed  by  the  owner,  and  should  be  fixed  by  long  iron  pins  driven 
into  the  street,  or  by  lines  cut  on  the  curbstone  across  the  street. 
In  building  close  to  the  party-lines  of  a  lot  it  is,  of  course,  of  great 
importance  that  the  building  does  not  encroach  upon  the  adjacent 
lot,  and  to  prevent  this  it  is  always  well  to  set  back  one  inch  from 
the  line,  thus  allowing  for  any  irregularities  or  projections  in  the 
wall. 

3.  DIAGONALS. — After  the  batter-boards  are  in  place  and 
properly  marked,  the  superintendent  should  require  the  contractor 
or  his  foreman  to  stretch  the  main  lines  of  the  building,  and  the 
superintendent  should  carefully  measure  the  diagonals,  as  A  B  and 
C  D,  Fig.  I,  with  a  steel  tape  ;  if  they  are  not  exactly  of  the  same 
length  the  lines  are  not  at  right  angles  with  each  other  and  should 
be  squared  until  the  diagonals  are  of  equal  length. 

On  fairly  level  ground  a  building  may  be  accurately  laid  out  by 
means  of  a  steel  tape,  using  multiples  of  3,  4  and  5  for  the  sides  and 
the  hypothenuse  of  a  right-angled  triangle.  The  larger  the  triangle 
the  more  accurate  will  be  the  work. 

4.  STAKING  OUT  BUILDINGS  IN  CITIES.— In  staking 
out  buildings  in  cities  of  the  first  and  second  class  the  building"  and 
property  lines  should  always  be  obtained  from  an  official  survey, 
furnished  at  a  nominal  charge,  by  the  surveyor  of  the  district 
authorized  by  the  city.  It  is  usual  also  to  have  the  district  surveyor 
give  the  street  and  party-lines  at  the  site  of  the  operation.  From 
these  main  lines  the  building  may  be  readily  staked  out  as  described 
above. 

In  reading  a  survey  care  must  be  exercised  to  determine  whether 
or  not  the  measurements  given  are  in  United  States  standards,  as 
frequently  the  unit  measurements  of  the  city  and  of  the  deeds  are 
not  standard,  and  may  vary  from  the  tape  measurements  as  muclr 
as  several  inches  in  a  hundred  feet. 

2.    FOUNDATIONS.    LIGHT  BUILDINGS. 

5.  NATURE  OF  SOILS.— The  architect  should  in  all  cases 
make  every  endeavor  to  discover  the  nature  of  the  soil  upon  which 
his  building  is  to  be  built  before  he  makes  his  foundation  plan.  For 
most  buildings  a  sufficient  idea  of  the  nature  of  the  soil  may  be. 


4 


BUILDING  CONSTRUCTION. 

■i 


(Ch.  I) 


gained  by  inquiry  amongst  builders  who  have  put  up  buildings  on  the 
adjacent  lots.  Many  soils,  however,  vary  greatly,  even  in  a  distance 
of  lOO  feet,  owing  to  a  decided  dip  of  the  strata,  and  on  all  such 
soils  much  trouble  and  annoyance  may  often  be  saved  by  having  bor- 
ings made  with  a  post-auger,  showing  the  composition  of  the  soil 
of  the  different  strata.  If  two  borings  made  on  different  sides  of 
the  site  show  about  the  same  depth  and  character  of  soil  it  may  be 
assumed  that  other  borings  would  give  the  same  result ;  but  if  the 
material  brought  up  by  the  first  two  borings  shows  a  difference  in 
the  character  of  the  soil,  or  indicates  that  the  strata  have  a  decided 
dip,  then  borings  should  be  made  all  around  the  foundations. 

Where  the  ground  has  been  filled  in,  or  made,  a  knowledge  of  the 
original  topography  of  the  soil  is  always  desirable.  This  information 
may  sometimes  be  obtained  from  official  county  or  city  maps  and 
is  of  great  assistance  in  the  designing  of  foundations  for  important 
buildings.  The  data  thus  obtained  should,  however,  be  supplemented 
by  test  borings  in  order  to  ascertain  the  character  of  the  original 
superstratum. 

For  ordinary  buildings  borings  to  the  depth  of  8  or  lo  feet  are 
generally,  sufficient,  although  a  6-  or  8-inch  auger  may  be  driven  to 
the  depth  of  20  or  25  feet  by  two  men  using  a  lever.  In  soft  soils  a 
pipe  must  first  be  sunk  and  the  auger. worked  inside  of  it.  A  smaller 
auger  will  answer  in  such  cases. 

For  dwellings  built  on  sand,  gravel,  clay  or  rock,  an  examination 
of  the  bottom  of  the  trenches,  and  a  few  tests  with  an  ordinary  crow- 
bar or  post-auger,  will  generally  be  all  that  is  necessary. 

When  borings  are  deemed  necessary  the  owner  should  be  advised 
of  the  fact,  and  his  authority  obtained  for  incurring  the  expense, 
which  should  be  defrayed  by  him. 

Different  soils  have  not  only  different  bearing  or  sustaining  pow- 
ers, but  also  various  peculiarities  which  must  be  thoroughly  under- 
stood and  considered  when  designing  the  foundation. 

An  architect  who,  as  a  draughtsman,  has  had  several  years'  expe- 
rience in  one  locality  before  practicing  for  himself,  will  naturally 
have  become  acquainted  with  the  peculiarities  of  the  soil  in  that 
vicinity ;  but  should  his  practice  extend  beyond  his  own  city,  he 
should  carefully  study  the  nature  and  peculiarities  of  the  soil  in  each 
different  locality  where  he  may  have  work,  and  also  obtain  all  the 
information  possible,  bearing  on  the  subject,  from  local  builders,  as 
•otherwise  he  may  have  serious  trouble. 


FOUNDATIONS.    LIGHT  BUILDINGS. 


5 


No  part  of  a  building  is  more  important  than  the  foundation,  and 
more  cracks  and  failures  in  buildings  will  be  found  to  result  from 
defective  foundations  than  from  any  other  cause  ;  and  for  any  such 
defects,  resulting  from  the  neglect  of  usual  or  necessary  precautions, 
the  architect  is  responsible  to  the  owner,  and  also  for  the  damage 
done  to  his  own  reputation. 

The  following  observations  are  intended  as  a  general  guide  in 
preparing  foundations  on  different  soils,  although  they  should  be 
supplemented  by  the  experience  of  local  builders  wherever  possible. 

6.  ROCK. — Rock,  when  it  extends  under  the  entire  site  of  the 
building,  makes  one  of  the  best  foundation  beds,  as  even  the  softest 
rocks  will  safely  carry  more  weight  than  is  likely  to  come  upon 
them. 

The  principal  trouble  met  with  in  building  on  rock  is  the  presence 
-of  water.  As  the  surface  water  cannot  readily  penetrate  the  rock  it 
collects  on  top  of  the  ledge  and  in  the  trenches  so  that  some  arrange- 
ment for  draining  it  away  should  be  provided.  If  the  ledge  falls 
off  to  one  side,  a  tile  or  stone  drain  may  be  built  from  the  lowest 
point  of  the  footings  to  a  point  near  the  surface  on  the  slope.  If  in 
a  sewer  district,  the  water  may  be  drained  into  the  sewer,  proper 
precautions  being  taken  for  trapping  and  ventilation.  If  there  is  no 
sewer  and  the  rock  does  not  fall  off,  a  pit  to  collect  the  seepage 
should  be  excavated  at  the  lowest  part  of  the  cellar  and  an  auto- 
matic arrangement  provided  for  raising  the  water  into  a  drain  laid 
above  the  surface  of  the  rock. 


Fig.  4.    Rock  Cut  to  Level  Planes. 


To  prepare  the  rock  for  the  footings,  the  loose  and  decayed  por- 
tions should  be  cut  away  and  dressed  to  a  level  surface.  If  the  sur- 
face of  the  rock  dips,  or  is  irregular  in  its  contour,  the  portion  under 
the  footings  should  be  cut  to  level  planes  or  steps,  as  shown  in 
Fig.  4.  In  no  case  should  the  footings  of  a  wall  rest  on  an  inclined 
bed. 

This  method  of  filling  in  the  depressions  in  rock  excavation  with 
concrete  to  a  level  bed  in  order  to  secure  a  firm  footing  is  the  one 
usually  employed  in  the  construction  of  all  large  buildings.  In  Fig. 
5  is  shown  an  example  of  this  construction,  illustrating  the  arrange- 


6 


BUILDING  CONSTRUCTION. 


(Ch.  I) 


ment  of  a  column  footing  of  the  New  York  Times  building,  one 
of  the  heaviest  structures  in  New  York. 


3i'nJchjral  Colo 


Broken  ^one 


Bed  Kock 

Fig.  5.    Filled-in  Rock  Fissure,  New  York  Times  Building. 


7.  FISSURES  AND  DIFFERENT  LEVELS.— If  these  are 
fissures  or  holes  in  the  rock,  they  should  be  filled  with  concrete,  well 
rammed;  or,  if  a  fissure  is  very  deep,  it  may  be  spanned  by  an  arch, 
of  brick  or  stone.  In  building  on  rock  it  is  very  desirable  that  the 
footings  shall  be  nearly  level  all  around  the  building ;  and  whenever 
this  is  not  the  case,  the  portions  of  the  foundation  which  start  at  the 
lower  level  should  be  laid  in  cement  mortar  and  with  close  joints,  as 
otherwise  the  foundations  will  settle  unequally  and  cause  cracks  to 
appear  above. 

8.  FOUNDATIONS  PARTLY  ON  ROCK.— Should  it  be  abso- 
lutely necessary  to  build  partly  on  rock  and  partly  on  soil,  the  foot- 
ings on  the  soil  should  be  made  very  wide,  so  that  the  settlement  will 
be  reduced  to  a  minimum.  The  footings  resting  on  the  rock  will  not 
settle,  and  the  least  settlement  in  those  resting  on  the  soil  will  be  sure' 
to  produce  cracks  in  the  superstructure,  and  perhaps  do  other 
damage. 

Building  on  such  a  foundation  bed  is  very  risky  at  best,  and  if 
possible  should  be  avoided. 


FOUNDATIONS.    LIGHT  BUILDINGS. 


7 


9.  CLAY. — This  soil  is  found  in  every  condition,  varying  from 
slate  or  shale,  which  will  support  any  possible  load,  to  a  soft,  damp 
material,  which  will  squeeze  out  in  every  direction  when  a  mod- 
erately heavy  pressure  is  brought  upon  it. 

Ordinary  clay  soils,  however,  when  they  can  be  kept  dry,  will 
carry  any  usual  load  without  trouble,  but  as  a  rule  clay  soils  give 
more  trouble  than  either  sand,  gravel  or  rock. 

In  the  first  place,  the  top  of  the  footings  must  be  carried  below 
the  frost  line  to  prevent  heaving,  and  for  the  same  reason  the  out- 
side face  of  the  wall  should  be  built  with  a  slight  batter  and  per- 
fectly smooth  surface.  The  frost  line  varies  with  different  localities, 
attaining  a  depth  of  six  feet  in  some  of  the  Northern  States,  although 
between  three  and  four  feet  is  the  usual  depth  reached.  The  effect 
of  freezing  and  thawing  on  clay  soils  is  very  much  greater  than  on 
other  soils. 

The  surface  of  the  ground  around  the  building  should  be  graded 
so  that  the  rain  water  will  run  away  from  the  building ;  and  in  most 
clays  subsoil  drains  are  necessary.  When  the  clay  occurs  in  inclined 
layers,  great  care  must  be  exercised  to  prevent  it  from  sliding ;  and 
when  building  on  a  side  hill  the  utmost  precautions  must  be  taken  to 
exclude  water  from  the  soil,  for  if  the  clay  becomes  wet  the  pressure 
of  the  walls  may  cause  it  to  ooze  from  under  the  footings.  The 
erection  of  very,  heavy  buildings  in  such  locations  must  be  con- 
sidered hazardous,  even  when  every  precaution  is  taken. 

Frequently  an  excellent  foundation  soil  is  found  underlaid  with  a 
thin  stratum  of  clay.  Where  such  a  stratum  exists  there  is  little 
danger  in  building  above  it,  provided  there  is  no  probability  of  adja- 
cent excavations  being  carried  below  the  clay  and  thus  allowing  it 
to  be  squeezed  out  by  the  pressure  on  the  footings. 

Should  it  be  necessary  to  carry  a  portion  of  the  foundations  to  a 
greater  depth  than  the  rest,  the  lower  portion  of  the  walls  should  be 
built  as  described  in  Article  7,  and  care  must  be  taken  to  prevent 
the  upper  part  of  the  bed  from  slipping.  Wherever  possible,  the 
footings  should  be  carried  at  the  same  level  all  around  the  building. 

10.  FOUNDATIONS  IN  HEAVY  BLUE  CLAY.— In  Eastern 
Maine,  where  the  soil  is  a  heavy  blue  clay,  and  freezes  to  the  depth 
of  four  feet,  it  is  customary  to  build  the  foundation  walls  as  shown 
in  Fig.  6,  the  footings  being  laid  dry,  to  act  as  a  drain,  and  the 
bottom  of  the  trench  being  slightly  inclined  to  one  corner,  whence 


8 


BUILDING  CONSTRUCTION.  (Ch.  I) 


a  drain  is  carried  to  take  away  the  water.  The  portion  of  the  trench 
outside  of  the  wall  is  also  filled  with  broken  stone  or  gravel  to  pre- 
vent the  clay  from  freezing  to  the  side  of  the  wall.  In  the  better 
class  of  work  the  outside  of  the  wall  is  plastered  smooth  with 
cement.  Sometimes  a  tile  drain  is  laid  just  outside  and  a  little 
below  the  footings. 


11.  CLAY  WITH  SAND  OR  GRAVEL.— If  the  clay  contains 
coarse  sand  or  gravel  its  supporting  power  is  increased,  and  it  is 
less  liable  to  slide  or  ooze  away. 

In  Colorado  the  top  soil  consists  principally  of  clay,  mixed  with 
fine  sand,  and  as  long  as  it  is  kept  dry  it  will  sustain  a  great  load 
without  settlement.  As  soon  as  it  becomes  wet,  however,  it  turns 
into  a  soft  mud,  which  is  very  compressible  and  treacherous.  For 
this  reason  the  footings  of  heavy  buildings  are  carried  through  the 
clay  to  the  sand  below.  A  peculiarity  of  this  soil  is  that,  although 
it  freezes,  it  has  never  been  known  to  heave.  Two-story  buildings 
are  therefore  often  built  on  top  of  the  ground,  and  as  long  as  water 
is  kept  away  from  the  walls  no  injury  results. 

12.  GRAVEL. — This  material  gives  less  trouble  than  any  other 


Fig.  6.    Foundation  in  Clay,  with  Stone  Drains. 


FOUNDATIONS.    LIGHT  BUILDINGS. 


9 


as  a  foundation  bed.  It  does  not  settle  under  any  ordinary  loads, 
and  will  safely  carry  the  heaviest  of  buildings  if  the  footings  are 
properly  proportioned.  It  is  not  affected  by  water,  provided  it  is 
confined  laterally,  so  that  the  sand  and  fine  gravel  cannot  wash  out. 
This  soil  also  is  not  greatly  aflfected  by  frost. 

13.  SAND. — This  material  a.lso  makes  an  excellent  foundation 
bed  when  confined  laterally,  and  is  practically  incompressible,  as. 
clean  river  sand  compacted  in  a  trench  has  been  known  to  support 
100  tons  to  the  square  foot. 

As  long  as  the  sand  is  confined  on  all  sides,  and  the  footings  are 
all  on  the  same  level,  no  trouble  whatever  is  encountered,  unless  it 
is  in  the  caving  of  the  banks  while  making  the  excavations.  Should 
the  cellar  be  excavated  to  different  levels,  however,  sufficient  retain- 
ing-walls  must  be  erected  where  the  depth  changes  in  order  to  pre- 
vent the  sand  of  the  upper  level  from  being  forced  out  from  under 
the  footings;  and  precautions  should  be  taken  in  such  a  case  to- 
prevent  water  from  penetrating  under  the  upper  footings. 

14.  LOAM  AND  MADE  LAND.— N6  foundation  should  start 
on  loam,  that  is,  soil  containing  vegetable  matter,  or  on  land  that 
has  been  made  or  filled  in,  unless  the  filling  consists  of  clean  beacht 
sand,  which,  when  settled  with  water,  may  be  considered  equal  in 
resisting  power  to  the  natural  soil. 

Loam  should  alwayS  be  penetrated  to  the  firm  soil  beneath,  and 
when  the  made  land  or  filling  overlies  a  firm  earth  the  footings 
should  be  carried  to  the  natural  soil.  When  the  filled  land  is  always 
wet,  as  on  the  coast  or  on  the  borders  of  a  lake,  piles  may  be  used, 
extending  into  the  firm  earth,  and  having  their  tops  cut  off  below 
the  low-water  mark;  but  piles  should  never  be  used  where  it  is  not 
certain  that  they  will  be  always  wet. 

15.  MUD  AND  SILT. — Under  this  heading  may  be  included 
all  marshy  or  compressible  soils  which  are  usually  saturated  with 
water. 

Foundations  on  such  soils  are  generally  laid  in  one  of  the  three 
following  ways:  i.  By  driving  piles  on  which  the  footings  are  sup- 
ported. 2.  By  spreading  the  footings  either  by  wooden  timbers, 
steel  beams  or  reinforced  concrete,  so  as  to  distribute  the  weight 
over  a  large  area.  3.  By  sinking  caissons  or  steel  wells  or  cylinders, 
filled  with  masonry,  to  hard  pan.  As  all  of  these  methods  are  more 
or  less  complicated  they  will  be  described  in  Chapter  11. 


10 


BUILDING  CONSTRUCTION. 


(Ch.  I) 


16.  SOILS  OF  PECULIAR  NATURE.— There  are  in  some 
localities  peculiar  conditions  in  the  soil  strata  with  which  those 
engaged  in  building  operations  should  be  familiar.  In  the  anthracite 
regions,  in  some  localities,  the  galleries  or  workings  lie  near  the 
surface,  and  it  is  necessary  to  locate  them  with  reference  to  the  lines 
of  the  building  so  that  the  important  piers  may  be  extended  down 
through  them. 

In  one  instance  it  was  necessary  to  entirely  rebuild  a  portion  of 
a  costly  building  in  Scran  ton.  Pa.,  because  an  apparently,  solid  foun- 
dation soil  was  undermined  by  a  subterranean  stream  which  flowed 
along  a  shale  substratum  and  then  down  into  an  abandoned  mine- 
working.  In  this  way  the  stream  had  tunnelled  the  upper  stratum, 
so  that  when  the  weight  of  the  almost  completed  building  was 
imposed  the  earth  gave  way  and  caused  dangerous  settlement. 

17.  BEARING  POWER  OF  SOILS.— The  best  method  of 
determining  the  load  which  a  particular  soil  will  bear  is  the  one 
involving  direct  experiment;  but  good  judgment,  aided  by  a  careful 
examination  of  the  soil,,  and  particularly  of  its  compactness  and  the 
amount  of  water  it  contains,  in  conjunction  with  the  following  table, 
will  enable  one  to  determine  with  reasonable  accuracy  its  probable 
supporting  power.  A  mean  of  the  values  given  below  may  be  con- 
sidered safe  for  good  examples  of  the  kinds  of  soils  quoted : 

TABLE  1. 

Safe  Bearing  Strengths  of  Foundation  Rocks  and  Soils. 


 CHARACTER   OF  SOIL.  sq'uTheToT 

Kock,  granite  in  hard,  compact  strata                                                     .  100  to  200 

Rock,  limestone   25  to  30 

Rock,  sandstone   18  to  25 

Rock,  soft  and  friable,  as  shale   5  to  10 

Clay,  thick  beds  and  dry  ,   4  to  6 

Clay,  thick  beds  and  moderately  dry   2  to  4 

Clay,  soft   I  to  2 

Gravel,  mixed  with  sand  and  well  cemented   8  to  lo 

Gravel,  coarse  and  dry,  well  compacted   6  to  8 

Sand,  compact  and  well  cemented   4  to  6 

Sand,  clean  and  dry  and  confined  in  natural  beds  ;   2  to  4 

Quicksand,  alluvial  soils,  etc   0.5  to  I 


In  case  it  is  desirable  to  exceed  the  maximum  loads  here  given, 
or  in  case  there  is  any  doubt  of  the  bearing  capacity  of  the  soil  or 
a  lack  of  precedent,  tests  should  be  made  in  several  places  on  the 


FOUNDATIONS. 


LIGHT  BUILDINGS. 


II 


bottom  of  the  trenches  to  determine  the  actual  load  required  to 
produce  settlement,  as  described  in  Article  20. 

18.  MUNICIPAL  REGULATIONS.— While  Table  I,  giving 
the  safe  unit-bearing  value  of  different  foundation  soils,  represents 
conservative  engineering  practice,  the  municipal  regulations  of  the 
locality  must  usually  be  observed,  as  the  several  cities  have  estab- 
lished such  values  in  their  building  law^. 

As  a  rule  it  is  required  that  these  vames  shall  be  used  in  propor-  1 
tioning  foundation  footings  where  the  soil  is  not  tested;  and 
deviations  are  allowed  from  these  values  when  the  soil  is  tested, 
the  test  being  witnessed  by  a  representative  of  the  building  depart- 
ment and  the  record  of  the  test  being  filed  with  the  bureau. 

The  New  York  building  law  stipulates  that  the  following  loads 
per  superficial  foot  shall  be  used  in  proportioning  foundation  foot- 
ings :  soft  clay,  one  ton  per  square  foot ;  ordinary  clay  and  sand 
together,  in  layers,  wet  and  springy,  two  tons  per  square  foot ;  loam, 
clay  or  fine  sand,  firm  and  dry,  three  tons  per  square  foot ;  very  firm, 
coarse  sand,  stiff  gravel  or  hard  clay,  four  tons  per  square  foot. 

The  Chicago  building  ordinance  relating  to  the  bearing  value  of 
foundation  soils  deals  specifically  with  the  soils  underlying  the  city. 
These  soils  are  of  a  clayey  nature  and  the  bearing  value  is  limited 
as  given  in  the  following  quotation  from  the  ordinance: 

'Tf  the  soil  is  a  layer  of  pure  clay  at  least  fifteen  feet  thick  without 
admixture  of  any  foreign  substance  excepting  gravel,  it  shall  not  be 
loaded  more  than  at  the  rate  of  3,500  pounds  per  square  foot.  If  the 
soil  is  a  layer  of  pure  clay  at  least  fifteen  feet  thick  and  is  dry  and 
thoroughly  compressed,  it  may  be  loaded  not  to  exceed  4,500  pounds 
per  square  foot. 

"If  the  soil  is  a  layer  of  dry  sand  fifteen  feet  or  more  in  thickness, 
and  without  admixture  of  clay,  loam,  or  other  foreign  substance,  it 
shall  not  be  loaded  more  than  at  the  rate  of  4,000  pounds  per 
square  foot. 

"If  the  soil  is  a  mixture  of  clay  and  sand  it  shall  not  be  loaded 
more  than  at  the  rate  of  3,000  pounds  per  square  foot." 

19.  EXAMPLES  OF  ACTUAL  LOADS  AND  TESTS.— 
On  Clay. — The  Capitol  at  Albany,  N.  Y.,  rests  on  blue  clay  con- 
taining frorn  60  to  90  per  cent  of  alumina,  the  remainder  being  fine 
sand,  and  containing  40  per  cent  of  water  on  an  average.  The  safe 
load  was  taken  at^2  tons  per  square  foot.   A  load  of  5.9  tons  applied 


12 


BUILDING  CONSTRUCTION.  (Ch.  I) 


on  a  surface  i  foot  square  produced  an  uplift  of  the  surrounding 
earth. 

The  Congressional  Library  at  Washington,  D.  C,  rests  on  yellow 

clay  mixed  with  sand.  It  was  found  that  it  required  about  ly/z 
tons  per  square  foot  to  produce  settlement,  and  the  footings  were 
proportioned  for  a  maximum  pressure  of  2^  tons. 

A  hard  indurated  clay,  containing  lime,  under  the  piers  of  a  bridge 
across  the  Ohio  River,  at  ?oint  Pleasant,  W.  Va.,  carries  approxi- 
mately 23^  tons  per  square  foot. 

On  Sand. — ''In  an  experiment  in  France  clean  river  sand  com- 
pacted in  a  trench  supported  100  tons  per  square  foot. 

"The  piers  of  the  Cincinnati  suspension  bridge  are  founded  on  a 
bed  of  coarse  gravel  12  feet  below  water;  the  maximum  pressure  is 
4  tons  per  square  foot. 

"The  piers  of  the  Brooklyn  suspension  bridge  are  founded  44  feet 
below  the  bed  of  the  river,  upon  a  layer  of  sand  2  feet  thick,  resting 
upon  bed  rock;  the  maximum  pressure  is  about  51^  tons  per  square 
foot."  * 

20.  METHODS  OF  TESTING.— Probably  the  easiest  method 
of  determining  the  bearing  power  of  the  foundation  bed  is  the  one 
involving  the  use  of  a  platform  from  3  to  4  feet  square,  having  four 
legs,  each  6  inches  square.  The  platform  should  be  set  on  the  bottom 
of  the  trench,  which  should  be  carefully  levelled  to  receive  the  legs. 
A  level  should  then  be  taken  from  a  stake  or  other  bench-mark  not 
liable  to  be  disturbed,  to  each  of  the  four  corners  of  the  platform, 
and  the  platform  then  loaded  with  dry  sand,  bricks,  stone  or  pig- 
iron,  as  may  be  most  convenient.  The  load  should  be  put  on  gradu- 
ally, and  frequent  levels  taken  unttl  a  sinkage  is  shown.  From  one- 
fifth  to  one-half  of  the  load  required  to  produce  settlement  is  gener- 
ally adopted  for  the  safe  load,  according  to  circumstances.  In  testing 
the  ground  under  the  Congressional  Library  building  a  travelling 
car  was  used,  having  four  cast-iron  pedestals,  set*4  f^et  apart  each 
way,  and  each  measuring  i  square  foot  at  the  base.  The  car  was 
moved  along  the  trenches,  and  halted  at  intervals  in  such  a  w-ay  as 
to  bring  the  whole  weight  of  the  car  and  its  load  upon  the  pedestals 
which  rested  on  the  bottom  of  the  trench.  In  this  case  the  car  was 
loaded  with  pig-lead. 

By  this  method,  if  the  legs  of  the  testing  apparatus  do  not  settle 
evenly,  it  is  impossible  to  tell  just  what  the  pressure  on  the  lowest 


*  Ira  O.  Baker,  American  Architect,  November  3,  1888. 


DESIGNING  THE  FOUNDATIONS. 


corner  amounts  to ;  and  it  is  not  safe  to  consider  it  more  than 
one-fourth  of  the  whole  load. 

In  testing  soils  by  using  a  small  square  bearing  area,  it  should 
be  observed  that  the  settlement  will  be  in  excess  of  that  which 
would  occur  from  the  same  load  on  a  continuous  footing.  This  is. 
explained  by  the  fact  that  the  square  end  of  the  post  or  pedestal 
forming  the  bearing  plate  of  the  testing  machine  has  four  cutting 
edges  which  tend  to  enter  the  soil  with  less  resistance  than  a  long 
footing  course  having  only  two  edges. 

21.  SOIL  TESTING  UNDER  NEW  YORK  STATE  CAP- 
ITOL.— In  testing  the  soil  under  the  State  Capitol  at  Albany,  N.  Y., 
the  load  was  placed  on  a  mast  12  inches  square,  held  in  a  vertical 
position  by  guys,  and  furnished  with  a  cross  frame  to  hold  the 
weights.  The  bottom  of  the  mast  was  set  in  a  hole  3  feet  deep,  iS 
inches  square  at  the  top  and  14  inches  square  at  the  bottom.  Small 
stakes  were  driven  into  the  ground  in  lines  radiating  from  the  center 
of  the  hole,  the  tops  being  brought  exactly  to  the  same  level,  so  that 
any  change  in  the  surface  of  the  ground  could  readily  be  detected 
and  measured  by  micans  of  a  straight-edge.  In  this  case  there  was 
no  change  in  the  surface  of  the  ground  until  the  load  reached  5.9 
tons,  when  an  uplift  of  the  surrounding  ground  was  noticed. 

3.    DESIGNING  THE  FOUNDATIONS. 

22.  PRELIMINARY  DATA.— Knowing  the  character  and  sup- 
porting power  of  the  soil  on  which  he  is  to  build,  the  architect  is 
prepared  to  design  his  foundation  plans,  but  in  no  case  should  this 
be  done  when  the  preceding  information  is  wanting. 

In  designing  the  foundations  the  first  point  to  be  settled  will  be 
the  depth  of  the  foundations ;  the  second,  whether  they  shall  be 
built  in  piers  or  in  a  continuous  wall ;  and  the  third,  the  width  of 
the  foundations. 

23.  DEPTH. — For  isolated  buildings  on  firm  soil,  the  depth  of 
the  foundations  will  generally  be  determined  by  the  depth  of  the 
basement  or  by  the  frost  line.  Even  where  there  is  no  frost,  and 
the  ground  is  firm,  the  footings  should  be  carried  at  least  2  feet 
below  the  surface  of  the  ground,  so  as  .to  be  below  the  action  of 
the  surface  water.  In  very  few  soils,  however,  is  it  safe  to  start 
the  foundations  at  a  less  depth  than  5  feet,  thou^i  in  a  temperate 


14 


BUILDING  CONSTRUCTION. 


(Ch.  I) 


climate,  such  as  that  of  the  Middle  States,  foundations  carried  to 
a  depth  of  3  feet  6  inches  give  little  trouble.    (See  Article  10.) 

The  depth  of  the  foundations  for  city  buildings,  built  near  ths 
lot  line,  should  be  governed  by  the  local  laws  bearing  on  the  sub- 
ject, by  the  character  of  the  soil,  and  by  the  probable  future  action 
of  the  owners  of  the  adjoining  property. 

In  most  cities  the  law  provides  that  any  lot  owner  who  excavates 
below  a  certain  depth,  usually  about  10  feet,  must  protect  the  walls 
of  the  adjoining  property  at  his  own  expense;  but  that  if  he  does  not 
excavate  below  that  depth,  10  feet,  the  adjoining  owners  must  them- 
selves protect  their  property  from  falling  in. 

It  is,  therefore,  always  wise  to  provide  against  any  such  future 
expense  and  trouble  by  carrying  the  footings,  at  least  those  of  the 
side  walls,  to  the  prescribed  limit,  above  which  the  owner  will  be 
responsible,  even  if  the  requirements  of  the  soil  or  building  do  not 
necessitate  it.  This  precaution  is  especially  important  when  the 
building  is  erected  on  sand. 

24.  CONTINUOUS  FOUNDATIONS  VERSUS  PIERS.— 
It  has  been  found  that  when  heavy  buildings  are  to  be  erected  on  soft 
or  compressible  soils  greater  security  from  settlement  may  be 
obtained  by  dividing  the  foundation  into  isolated  piers,  as  described 
in  Chapter  II. 

When  building  on  firm  soils,  however,  no  advantage  is  gained  by 
pursuing  this  method,  unless  the  walls  of  the  building  are  themselves 
composed  of  piers  with  thin  curtain-walls  between,  in  which  case  the 
foundations  under  the  piers  and  walls  should  be  built  of  different 
widths,  and  not  bonded  together,  as  described  in  Article  33. 

When  the  walls  are  continuous,  however,  and  of  the  same  thick- 
ness throughout,  the  foundation  should  be  continuous.  The  architect 
should  constantly  bear  in  mind  that  in  all  kinds  of  building  construc- 
tion the  simplest  methods  are  almost  always  the  best,  and  that  com- 
plicated arrangements  and  the  use  of  iron,  etc.,  in  foundations,  at 
least  on  firm  soils,  should  be  avoided. 

25.  PROPORTIONING  THE  FOOTINGS.  —  Whether  the 
foundations  are  continuous  or  divided  into  piers,  the,  area  of  the 
footings  should  be  carefully  proportioned  to  the  weight  ivliich  they 
support  and  to  the  bearing  power  of  the  soil.  The  former  is  per- 
haps the  most  important  of  all  considerations  in  designing  the  foot- 
ings.   While  th%  safe  bearing  power  of  the  soil  ought  not  to  be 


DESIGNING  THE  EOUNDATIONS.  15 

exceeded,  it  is,  on  most  soils,  not  of  so  much  importance  as  a  pro- 
portioning of  the  footings,  such  that  the  pressure  on  the  soil  from 
every  square  foot  of  the  footings  zvill  he  the  same.  If  this  condi- 
tion always  obtained  there  would  be  few  cracks  in  the  mason  work 
of  buildings,  as  such  cracks  are  caused,  not  by  a  uniform  settle- 
ment of  an  inch  or  two,  wdiich  with  most  buildings  would  not  be 
noticed,  but  by  an  unequal  settlement. 

In  proportioning  the  area  of  the  footings  the  architect  should 
carefully  compute  the  w^eights  coming  upon  each  pier,  and  the 
weight  of  and  the  loads  supported  by  the  walls,  and  record  the  same 
in  a  memorandum  book  or  otherwise  file  for  reference. 

He  should  then  decide,  by  means  of  Table  I,  Article  17,  and  by 
an  examination  of  the  ground,  or,  if  necessary,  by  actual  tests,  the 
bearing  weight  which  it  appears  advisable  to  assume.  By  dividing 
the  load  on  the  various  footings  by  this  assumed  carrying  load,  the 
proper  area  of  the  footings  will  be  found. 

The  pressure  under  piers  supporting  a  tier  of  iron  columns  may 
be  made  10  per  cent  more  than  that  under  a  brick  v^all,  so  that  the 
piers  may  settle  a  little  more  to  allow  for  the  compression  in  the 
joints  of  the  mason  work. 

26.  COMPUTING  THE  WEIGHT.— /^t  computing  the  zveight 
to  be  supported  by  the  footings  the  live  or  movable  loads  and  the 
dead  loads  should  be  computed  separately.  In  building  on  any  com- 
pact soil,  the  object  in  carefully  proportioning  the  footings,  as 
has  been  stated,  is  not  so  much  to  prevent  any  settling  of  the  build- 
ing as  a  whole,  but  to  provide  for  a  uniform  settling  of  all  portions 
of  it,  so  that  the  floors  will  remain  level  and  no  cracks  be  developed 
in  the  walls.  In  order  to  secure  this  result,  it  is  necessary  that  the 
loads  for  which  the  footings  are  proportioned  shall  agree  with  the 
actual  conditions  as  closely  as  possible.*  Thus  the  dead  load  under 
the  walls  of  a  five-story  building  would  be  a  considerable  item,  while 
the  dead  load  under  a  tier  of  iron  columns  would  be  much  less  in 
proportion  to  the  floor  area  supported ;  and,  as  the  dead  load  is 
always  constant  and  the  live  load  one  which  may  greatly  vary,  only 
the  amount  of  the  live  load  that  will  probably  be  supported  by  the 
footings  most  of  the  time  should  be  considered. 

For  warehouses,  stores,  etc.,  about  50  per  cent  of  the  live  load  for 


*  Foundations  shall  be  proportioned  to  the  actual  average  loads  they  will  have  to  carry 
in  the  completec^  and  occupied  building,  and  not  to  theoretical  or  occasional  loads. — 
Chicago  Building  Ordinance. 


i6  BUILDING  CONSTRUCTION.  (Ch.  I) 


which  the  floor  beams  are  proportioned  should  be  added  to  the  dead 
load  supported  on  the  footings.  ♦ 

For  office  buildings,  hotels,  etc.,  the  weight  of  the  people  who 
occupy  them  should  be  neglected  altogether  in  proportioning  the 
footings,  and  only  about  15  pounds  per  square  foot  of  floor  allowed 
to  cover  the  weight  of  furniture,  safes,  books,  etc.  Actual  statistics 
show  that  the  permanent  average  loads  in  such  buildings  do  not 
exceed  the  above  limit. 

For  theatres  and  similar  buildings  some  allowance  should  probably 
be  made  for  the  weight  of  people,  the  actual  amount  depending  upon 
the  arrangement  of  the  plan  and  character  of  the  soil. 

27.  BUILDING  ORDINANCES.— While  the  data  given  above 
represent  conservative  practice  in  regard  to  the  percentage  of 
the  live  load  to  be  assumed  in  designing  foundations,  it  must  be 
observed  that  this  is  regulated  by  law  in  the  larger  cities. 

Many  building  codes  throughout  the  country  are  compiled,  with 
modifications,  from  the  code  of  the  city  of  New  York,  so  that  the 
following  quotation  from  the  portion  of  the  code  relating  to  the 
proportioning  of  footings  will  be  found  useful  here : 

'The  loads  exerting  pressure  under  the  footings  of  foundations 
in  buildings  more  than  three  stories  in  height  are  to  be  computed  as 
follows :  For  warehouses  and  factories  they  are  to  be  the  full  dead 
load  and  the  full  live  load  established  by  this  code.  In  stores  and 
buildings,  for  light  manufacturing  purposes,  they  are  to  be  full  dead 
load  and  75  per  cent  of  the  live  load  established  by  this  code.  The 
same  applies  to  churches,  school-houses  and  places  of  public 
assembly.  In  oflice-buildings,  hotels,  dwellings,  apartment-houses, 
tenement-houses,  lodging-houses  and  stables,  they  are  to  be  the  full 
dead  load  and  60  per  cent  of  the  live  load  established  by  this  code. 
The  footings  must  be  designed  to  distribute  the  loads  as  uniformly 
as  possible,  so  as  not  to  exceed  the  safe  bearing  capacity  of  the 
soil  as  established  by  this  code." 

28.  LIVE  LOADS  AND  UNEQUAL  SETTLEMENTS.— 
Almost  any  soil,  after  it  has  been  compacted  by  the  dead  weight  of  a 
building,  will  carry  a  shifting  load  of  people  without  further  settle- 
ment ;  while  if  the  footings  are  computed  to  carry  the  full  live  loads 
for  which  the  floor  beams  are  designed,  it  will  be  found  that  when 
the  building  is  finished  the  actual  loads  on  the  footings  under  the 
walls  will  be  much  greater  than  under  the  interior  piers;  and  if 


DESIGNING 


THE  FOUNDATIONS. 


17 


the  ground  settles  at  all  during  building  the  probabilities  are  that 
the  floors  of  the  building  will  be  higher  in  the  middle  than  at  the 
walls. 

29.  CALCULATIONS  FOR  FOOTING  WIDTHS.— Example 
I. — Assume  that  a  six-story  and  basement  warehouse  is  to  be 
erected  on  an  ordinary  sand  and  gravel  foundation.  The  building 
is  to  be  50  feet  wide,  with  two  longitudinal  rows  of  columns  and 
girders.  What  should  be  the  width  of  the  footings  under  the  walls 
and  columns? 

Solution. — The  load  on  one  lineal  foot  of  footing  under  the  side 
walls  will  consist  of  about  140  cubic  feet  of  brick  and  stone  work, 
weighing  about  17,000  pounds.*  One  lineal  foot  of  wall  will  also 
support  about  8  square  feet  of  each  floor  and  the  roof.  Assume 
also  that  the  floors  are  of  steel  beams  and  terra-cotta  tile,  with  con- 
crete filling,  weighing  altogether  75  pounds  to  the  square  foot,  and 
that  the  roof  is  of  the  same  material,  weighing  60  pounds  to  the 
square  foot.  Then  the  dead  load  from  the  six  floors  and  roof  will 
amount  to  4,080  pounds.  The  first,  second  and  third  floors  are 
intended  to  support  150  pounds  to  the  square  foot,  and  those  above 
100  pounds  to  the  square  foot.  The  possible  weight  of  snow  on  the 
roof  will  not  be  taken  into  account.  There  miight  then  be  a  possible 
live  load  on  the  footing  of  6,000  pounds,  but  as  it  is  improbable  that 
each  floor  will  be  loaded  all  over  at  the  same  time,  and  as  some 
space  must  be  reserved  for  passages,  etc.,  the  actual  live  load  will 
probably  not  exceed  for  any  lenglh  of  time  50  per  cent  of  the 
assumed  load,  or  3,000  pounds.  Adding  these  three  loads  together, 
the  wall  loads,  floor  loads  and  live  loads,  there  results  24,080  pounds 
as  the  load  on  one  lineal  foot  of  footing.  By  allowing  6,000  pounds, 
3  tons,  for  the  bearing  power  of  the  soil,  and  by  dividing  the  load  by 
this  amount,  the  required  width  of  the  footing  is  found  to  be  4  feet. 
The  load  on  the  footings  under  the  columns  will  consist  only  of  the 
weight  of  the  floors,  roof  and  live  load,  plus  the  weight  of  the  tier 
of  columns,  which  will  be  so  small  in  proportion  to  the  other  loads 
that  it  need  not  be  considered.  If  the  columns  are  14  feet  apart 
longitudinally,  each  one  will  support  224  square  feet  of  each 
floor,  so  that  the  total  dead  load  on  the  footing  under  the  columns 
will  amount  to  114,240  pounds,  and  the  possible  live  load  will 
amount  to  168,000  pounds.  As  it  is  hardly  possible  for  every 
square  foot  of  floor  in  every  story  to  be  loaded  to  its  full  capacity 

*  For  weight  per  cubic  feet  of  materials,  see  table  in  Appendix. 


i8 


BUILDING  CONSTRUCTION. 


(Ch.  I) 


at  the  same  time,  it  will  probably  be  nearer  the  actual  conditions  if 
only  50  per  cent  of  the  total  live  load,  or  84,000  pounds,  are  taken, 
making  a  total  load  on  the  footing  of  198,240  pounds,  which  will 
require  33  square  feet  in  the  area  of  the  footing.  But  as  there 
will  be  no  shrinkage  or  compression  in  the  iron  columns,  it  will  be 
better  to  reduce  this  area  10  per  cent,  making  the  footing  5^  feet 
square,  with  an  area  slightly  in  excess  of  30  square  feet. 

The  above  calculation  should  be  filed,  or  entered  in  a  memoran- 
dum book,  kept  for  the  purpose,  somewhat  as  follows : 

DATA  FOR  FOOTINGS.  * 
UNDER  ONE  FT.  OF  SIDE  WALLS.  UNDER  COLUMNS. 

Cubic  feet  of  brickwork,  108  @  120—12,960  lbs. 
Cubic  feet  of  stonework,  28®  150=  4,200 

Total  weight  of  wall  17,160  lbs  Nothing 

Floor  area  supported  8  □  '  16  x  14=  224  □ 

Weight  of  floors  per  □  '  75  lbs. 
"Weight  of  roof    per  □  '  60  lbs. 

Total  for  six  floors  and  roof:  510x8=  4,080  510x224=114,240 

Live  load  per  □  ' — 

1st,  2d  and  3d  floors,  150  lbs. 

3d,  4th  and  5th  floors,  100  lbs. 

Total  live  load,  8  x  750=6,000  750  x  224=  168,000 

50^  of  this  =   3,000   84,000 

Total  load  24,240  198,240 

Assumed  bearing  load,  6,000  lbs. 

Width  of  footings  under  wall,  4  ft.;  under  columns,  33  □  '  less  10%,  or  5'  6"  x  5'  6". 

The  front  and  rear  walls,  if  continuous,  would  not  have  to  sup- 
port any  floor  loads,  and  the  footings  should  be  reduced  in  pro- 
portion. The  footings  under  the  piers  supporting  the  ends  of  the 
girders  should  also  be  separately  computed. 

30.  FOOTING  WIDTHS  IN  GENERAL.— In  the  case  of 
light  buildings  it  will  often  be  found  that  the  computed  width  of 
footings  will  be  less  than  that  required  by  the  building  ordinances, 
in  which  case  it  will  of  course  be  necessary  to  comply  with  such 
ordinances  or  building  laws.  As  a  rule,  the  footings  under  a 
foundation  wall  should  be  at  least  12  inches  wider  than  the  thick- 
ness of  the  wall  to  give  it  stability.  Even  in  light  buildings  the 
footings  under  the  different  portions  of  them  should  be  carefully 
proportioned,  so  that  all  will  bring  the  same  pressure  per  square 
foot  on  the  ground.  In  cases  where  the  width  of  the  footing  is 
regulated  by  the  building  law,  the  pressure  per  square  foot  under 
the  footing  should  be  computed,  and  the  footings  under  all  piers, 
etc.,  proportioned  to  this  standard.    In  cases  where  a  high  tower 


DESIGNING  THE  FOUNDATIONS, 


19 


adjoins  a  lower  wall  the  footings  under  the  two  portions  must  be 
carefully  proportioned  to  the  weight  on  each;  otherwise  the  wall 
may  crack  where  it  is  bonded  into  the  tower. 

31.  CALCULATIONS  FOR  FOOTING  WIDTHS.— £.r- 
ample  II. — To  illustrate  the  manner  in  which  the  width  of  the  foot- 
ings should  be  proportioned  when  the  pressure  under  the  footings 
is  very  light,  the  following  example  will  be  considered : 

A  one-story  stone  church  has  side  walls  20  inches  thick  and  22 
feet  high  above  the  footings  and  a  tower  at  the  corner  60  feet  high, 
the  first  22  feet  being  24  inches  thick  and  the  balance  20  inches 
thick.  The  roof  is  supported  by  trusses  and  purlins,  so  that  only 
the  lower  6  feet  of  the  roof  rest  on  the  side  walls.  The  side  walls 
also  carry  6  feet  of  the  floor.  The  tower  has  a  flat  roof  12  feet 
square. 

Solution. — The  computations  for  the  widths  on  the  soil  under  the 
side  walls  and  under  the  tower  wall  will  be  as  follows : 


UNDER  SIDE  WALLS. 
Stonework,  22'  x  20"  =  36-3 

cu.ft.  at  150  lbs.  per  cu. ft.,  5,500  lbs. 
Weight  of  first  floor, 

130  lbs.  X  6  n  '=     780  " 
Weight  of  roof  below  purlin, 

40  lbs.  X  6  □  '=     240  " 


UNDER  TOWER  WALL. 
Stonework,   22'  x  24"=  ...      44  cu.  ft. 

38'X22"=  ...     631^  " 


I07¥x  150=   16,100  lbs. 

Weight  of  floor,  130  X  6=. .  780  " 
Weight  of  roof,    40  x  6=. .       240  ** 


Total  weight  on  soil  17,120 


Total  weight  on  soil  6,520  " 

Width  of  footings,  3  ft. 

Pressure  per  □  '  under  footings,  2,173  ^bs. 

Width  of  footings  under  tower,  17,  i20-f  2,173  =  7.8  ft. 

In  this  case  the  width  of  the  footings  under  the  side  wall  should 
be  determined  by  the  question  of  stability,  and  should  not  be  less 
than  3  feet.  Then  if  the  pressure  under  the  tower  is  reduced  to 
the  same  unit  per  square  foot,  the  tower  footings  will  need  to  be 
nearly  8  feet  wide.  On  firm  soils,  however,  such  as  sand,  gravel  or 
compact  clay,  it  will  not  be  necessary  to  make  the  footings  as  wide 
as  this,  as  the  soil  will  probably  not  settle  appreciably  under  a  con- 
siderably greater  pressure ;  so  that  if  the  footings  of  the  tower  are 
made  6  feet  wide,  there  will  probably  be  no  danger  of  unequal 
settlement.  Of  course  the  greater  the  unit  pressure  on  the  soil  the 
more  exact  must  be  the  proportioning  of  the  footings. 

32.  CENTER  OF  PRESSURE  '  TO  COINCIDE  WITH 
CENTER  OF  BASE.— In  order  that  the  walls  and  piers  of  a 
building  may  settle  uniformly  and  without  producing  cracks  in  the 
superstructure,  it  is  not  only  essential  that  the  area  of  the  footings 


20 


BUILDING  CONSTRUCTION. 


(Ch.  I) 


shall  be  in  proportion  to  the  load  and  to  the  bearing  power  of  the 
soil,  but  also  that  the  center  of  pressure  (a  vertical  line  through  the 
center  of  gravity  of  the  weight)  shall  pass  through  the  center  of 
the  area  of  the  foundation. 

'  This  condition  is  of  the  first  importance,  for  if  the  center  of 
pressure  does  not  coincide  with  the  center  of  the  base  the  ground 
will  yield  the  most  on  the  side  which  is  pressed  the  most;  and  as 
the  ground  yields,  the  base  assumes  an  inclined  position  and  carries 
the  lower  part  of  the  structure  with  it,  thus  producing  unsightly 
cracks,  if  nothing  more. 


Center  of  Pressure  and  Center  of  I'.ase. 
Fig.  7.    Narrow  Offsets.  Fig.  8.    Wide  Offsets. 


A  case  in  which  a  violation  of  this  rule  cannot  w^ll  be  avoided 
is  the  case  of  a  foundation  under  the  side  wall  of  a  building,  where 
the  footing  is  not  allowed  to  project  beyond  the  lot  line.  In  this  con- 
struction the  center  of  pressure  is  indicated  by  the  downward  arrow, 
and  the  center  of  base  by  the  upward  arrow,  Fig.  7.  It  is  evident 
that  the  intensity  of  the  pressure  is  greatest  on  the  portion  of  the 
footing  to  the  right  of  the  center  of  base,  and  the  footing  will  con- 
sequently settle  obliquely,  as  shown  in  the  figure,  with  a  tendency 
to  throw  the  wall  outward.  This  tendency  may  be  counteracted  by 
tying  the  wall  securely  to  the  floor  joists,  but  it  is  much  better  to 
make  some  arrangement  by  which  the  footing  will  settle  evenly. 
Where  it  is  absolutely  necessary  to  build  the  footing  without  pro- 
jecting beyond  the  lot  line,  the  former  should  be  carefully  built  of 
concrete,  dimension  stone  or  hard  bricks  well  grouted  in  cement 
mortar,  and  the  footing  should  be  no  wider  than  is  absolutely 
demanded  by  the  nature  of  the  soil.  The  offsets  on  the  inside  of  the 
wall  should  be  so  proportioned  that  a  line  drawn  through  their 


DESlGXrXG  THE  FOUNDATIONS. 


21 


edges  will  make  an  angle  of  not  less  than  60  degrees  with  the 
horizontal.  The  footing  shown  in  Fig.  7  is  to  be  preferred  to 
that  shown  in  Fig.  8. 

Sometimes  the  center  of  pressure 
or  of  weight  is  inside  of  the  center 
of  resistance  of  the  soil,  . a  result  due 
to  the  concentration  of  heavy  beam 
or  girder  loads  toward  the  inside  edge 
of  the  wall.  Where  this  condition 
exists  the  tendency  is  to  incline  the 
wall  inward,  and  this,  instead  of 
diminishing,  tends  to  increase  the 
stability  of  the  structure,  as  the 
floor  systems,  and  the  opposite  and 
adjacent  walls,  preclude  the  pos- 
sibility of  any  failure*  in  this  direc- 
tion. 

33.  CRACKS  IN  BUILDINGS.— Fig.  9  illustrates  another 
case  in  which  the  center  of  pressure  comes  outside  of  the  center  of 
base,  and  in  consequence  of  which  the  wall  inclines  outward,  pro- 
ducing cracks  over  the  opening.  This  is  a  very  common  occurrence 
in  brick  and  stone  walls  in  which  there  are  wide  openings.  In  such 
cases  the  footing  under  the  opening  should  either  be  omitted  entirely 
or  made  narrower  there  than  it  is  under  the  pier,  and  the  two 
footings  should  not  be  bonded  together.  Where  several  openings 
occur  one  above  the  other,  as  in  Fig.  10,  and  the  footings  are  con- 


Fig.  9. 


Center  of  Pressure  Outside 
)f  Center  of  Base. 


Fig.    10.     Incorrect  Method. 
Continuous  Wall. 


Fig.  IT.    Correct  Method. 
Separate    Piers    and   Dwarf  Walls. 


22  BUILDING  CONSTRUCTION.  (Cii.  I) 

tinned  under  the  opening,  the  unequal  settlement  of  the  footings 
will  very  likely  produce  cracks  over  all  the  openings,  the  side  walls 
inclining  slightly  outward.  Where  the  width  of  the  opening  is  8 
feet  or  more,  and  the  bottom  of  the  opening  is  not  a  great  distance 
above  the  footings,  the  latter  under  the  wall  on  each  side  should 
be  treated  as  if  they  were  under  piers,  as  shown  in  Fig.  ii,  and 
the  space  between  the  footings  should  be  filled  in  with  a  dwarf 
wall  only.  If  the  bottom  of  the  opening  is  twice  its  width  above 
the  foundation,  the  wall  under  it  will  distribute  the  weight  equally 
over  the  footings  and  the  settlement  will  be  uniform. 

As  a  rule  the  foundation  of  one  wall  should  never  be  bonded  into 
that  of  another  which  is  either  much  heavier  or  much  lighter  than 
itself. 

The  footings  should  also  be  proportioned  so  that  the  center  of 
pressure  will  fall  a  short  distance  inside  of  the  center  of  the  base, 
in  order  to  make  sure  that  it  will  not  fall  outside  of  it.  Any  inward 
inclination  of  the  wall,  as  previously  explained,  is  rendered  impos- 
sible by  the  interior  walls  and  by  the  floors,  while  any  outward 
inclination  can  be  conteracted  only  by  anchors  and  by  the  bond  of 
the  masonry.  A  slight  deviation  of  the  center  of  pressure  outside 
of  the  center  of  base  has  a  rnarked  effect,  and  is  not  easily  counter- 
acted by  anchors. 

In  Chicago  an  omission  of  from  i  to  2  per  cent  of  the  weight, 
by  leaving  openings,  usually  causes  sufficient  inequality  in  the 
settlement  to  produce  unsightly  cracks.* 

Where  slight  dififerences  in  weight  occur,  cracks  may  generally 
be  prevented  by  building  in  hoop-iron  ties,  rods  or  beams  over  the 
openings.  It  is  also  a  wise  precaution,  where  one  wall  joins 
another,  either  in  the  middle  or  at  the  corner  of  a  building,  to  tie 
the  walls  together  by  long  iron  anchors  built  into  the  walls  about 
every  six  feet  in  height. 

34.  FOOTINGS  AT  DIFFERENT  LEVELS.— In  all  cases 
where  the  foundations  of  a  new  building  go  down  to  a  greater 
depth  than  those  of  an  existing  adjacent  building  care  must  be 
taken  to  prevent  the  earth  from  sliding  from  under  the  footings 
of  the  existing  building,  and  threatening  its  destruction.  Usually 
the  only  safe  plan  is  to  resort  to  ''underpinning"  as  described  in 
Chapter  III. 


*  Ira  O.  Baker    in  "Masonry  Construction." 


FOUNDATIOXS.    SUPERIXTENDEXCE.  23 

It  should  be  observed  also  that  many  basement  plans  of  impor- 
tant buildings  provide  for  dififerent  floor  levels  in  the  several  sec- 
tions of  the  building.  For  instance,  the  boiler-room  and  engine- 
room  may  be  carried  down  in  order  to  provide  greater  head-room. 
In  such  cases  the  position  of  each  column  and  wall  footing  should 
be  examined  to  see  if  it  is  deep  enough  to  prevent  the  pressure 
upon  it  from  forcing  out  the  earth  into  the  more  deeply  excavated 


doi/er  F^oom 


Fig.  \2.     Footing's  at  Different  Levels 


area.  This  condition  is  illustrated  in  Fig.  12,  which  shows  the 
normal  basement  level  at  a,  a.  and  the  boiler-room  floor  level  at 
h,  b.  At  c  is  shown  one  of  the  important  column  piers  of  the 
structure,  with  its  footing  near  the  deeper  excavation  and  at  a 
higher  level.  The  great  pressure  on  the  column  footing  tends  to 
force  the  earth  out  from  under  it,  and  to  overturn  the  retaining 
wall  at  d,  and  the  footing  should  be  carried  down  to  the  level 
indicated  by  the  dotted  lines.  When  the  soil  is  very  stable  a 
footing  of  this  nature  may  generally  be  considered  safe,  if  the  line 
e,  c  makes  an  angle  of  not  more  than  30  degrees  with  the 
horizontal.  It  is  also  necessary  in  designing  foundations  to  see  that 
column  and  wall  footings  are  deep  enough  to  permit  the  installa- 
tion of  engine  foundations,  tanks  or  sumps  without  endangering 
the  footings. 

4.  SUPERINTENDENCE. 

35.  MATTERS  REQUIRING  SPECIAL  ATTENTION.— 
In  inspecting  the  excavation  the  superintendent  should  first 
examine  the  lines  to  see  that  the  building  has  been  correctly  staked 


24  BUILDING  CONSTRUCTION.  (Ch.  I) 


out,  and  that  the  excavation  is  being  carried  at  least  6  inches  out- 
side of  the  wall  lines,  so  as  to  give  room  for  pointing  or  cementing. 
If  the  walls  are  built  against  the  bank  it  will  be  impossible  to  point 
up  the  joints  on  the  outside,  and  the  back  of  the  walls  not  being 
exposed,  the  masons  are  apt  to  slight  that  part  of  the  work  to  the 
future  detriment  of  the  building;  and  if  the  excavation  is  not  made 
large  enough  at  first,  it  catises  much  trouble  and  vexation,  as  the 
work  cannot  be  done  as  cheaply  afterward,  and  the  stone-masons 
will  very  likely  complain  about  being  delayed. 

The  superintendent  should  also  see  that  the  finished  grade  is 
plainly  marked  on  some  fixed  object  and  should  caution  the  work- 
men not  to  dig  the  trenches  below  the  levels  marked  on  the  draw- 
ings. If  the  trenches  are  excavated  below  the  proper  levels,  they 
must  not  be  refilled  with  earth,  as  the  footings  should  start  on  the 
solid  bottom  of  the  trenches ;  and  as  this  will  require  more  masonry 
than  the  contractor  estimated  on,  he  will  be  c^uite.  sure  to  call  for 
an  extra  payment  for  the  same  from  the  owner,  unless  the  exca- 
vating is  included  in  his  contract,  in  which  case  he  will  have  to 
settle  with  the  excavator.  For  this  reason  it  is  a  good  plan  to  have 
the  excavating  included  in  the  contract  for  the  foundation. 

It  is  good  practice,  also,  and  especially  in  the  construction  of 
heavy  buildings,  to  have  the  bottom  of  footing  trenches  and  pier 
excavations  thoroughly  rammed  so  as  to  further  compress  the  soil 
before  the  footings  are  put  in. 

The  superintendent  should  also  examine  the  character  of  the 
soil  at  the  bottom  of  the  excavation,  and  if  he  finds  that  it  is  not 
such  as  was  expected,  the  foundations  should  be  changed  or  car- 
ried deeper,  as  previously  described.  In  case  water  is  encountered 
in  making  the  excavations,  some  provision  should  be  made  for 
draining  the  cellar,  either  by  laying  tile  drains  around  the  footings, 
or  by  laying  the  bottom  courses  dry  and  connecting  them  with 
stone  drains,  as  described  in  Articles  6  and  lo.  The  specifications 
should  provide  that  the  contractor  is  to  keep  the  trenches  free  from 
water  while  the  walls  are  being  built.  In  places  where  the  water 
cannot  be  drained  off  it  must  be  removed  by  a  pump,  either 
worked  by  hand  or  by  steam.  When  the  excavation  is  made  close 
to  an  adjoining  building  the  superintendent  should  see  that  the  ' 
contractor  has  made  proper  provision  for  shoring  or  otherwise  pro- 
tecting the  adjacent  walls. 


Chapter  II. 


Foundations  on  Compressible  Soils 


36.  COMPRESSIBLE  SOILS  IN  GENERAL.— The  soils  of 
this  class  that  are  met  with  in  preparing  the  foundations  of  buildings 
are  often  located  along  the  shores  of  large  bodies  of  water  and  hence 
generally  permeated  with  moisture  to  within  'a  few  feet  of  the 
surface. 

For  such  soils  pile  foundations  are  usually  the  cheapest  and  most 
reliable.  On  a  soil  like  that  underlying  Chicago,  and  having  a  sup- 
porting power  of  from  i}^  to  2)72  tons  per  square  foot,  spread  foun- 
dations may  be  used  with  satisfactory  and  economic  results,  whereas 
it  would  require  piles  over  40  feet  long  to  reach  hard-pan. 

Occasionally  it  is  necessary  to  build  on  ground  that  has  been  filled 
in  to  a  considerable  depth,  and  in  which  water  is  not  present ;  and 
in  that  case  timber  piles  cannot  be  used.  In  such  cases  wells  of 
solid  masonry  with  iron  casings,  or  pneumatic  caissons,  may  be 
sunk  to  bed-rock  or  hard-pan,  as  hereinafter  described,  or  concrete 
piles  may  be  used. 

I.    PILE  FOUNDATIONS 

37.  OBJECTIONS  TO  PILE  FOUNDATIONS.— When  it  is 
necessary  to  build  on  a  compressible  soil  that  is  constantly  saturated 
with  water  and  of  considerable  depth,  the  cheapest  and  generally  the 
best  foundation  bed  is  obtained  by  driving  wooden  piles.  Pile  foun- 
dations cannot  always  be  used  without  danger  to  adjoining  buildings 
because  the  method  of  driving  generally  employed  is  liable  to  jar 
and  weaken  the  neighboring  walls  and  foundations.  It  has  also 
been  claimed  that  driving  piles  in  a  soil  such  as  that  under  Chicago, 
wdthin  a  few  feet  of  buildings  having  spread-foundations,  has  a 
tendency  to  cause  the  latter  to  settle  so  as  to  necessitate  under- 
pinning. 

•  On  driving  the  first  piles  for  the  Schiller  building,  Chicago,  it  was 
found  that  an  adjoining  building  had  settled  6  inches,  and  it  had  to 
be  raised  on  screws. 

The  driving  of  piles  also  causes  a  readjustment  of  the  particles  of 


25 


26 


BUILDING 


CONSTRUCTION. 


(Ch.  II) 


clay  and  sand  into  a  jelly,  thus  greatly  diminishing  the  resisting 
properties.  These  objections,  however,  are  not  of  so  much  moment 
when  the  adjoining  buildings  are  supported  by  piles. 

38.  CLASSES  OF  PILES.— A  great  many  kinds  of  piles  are 
used  in  engineering  works,  but  for  the  foundations  of  buildings 
wooden  piles  are  at  present  used  oftener  than  any  other  kind. 

The  different  conditions  under  which  piles  are  used  for  supporting 
buildings  may  be  classed  as  follows : 

1.  When  the  compressible  soil  is  not  more  than  40  feet  deep  and 
overlies  a  bed  of  rock,  gravel,  sand  or  clay,  long  piles  should  be 
driven  to  the  rock,  or  to  a  distance  of  from  one  to  two  feet  into  the 
clay  or  sand,  in  which  cases  they  may  be  considered  to  act  as 
columns. 

2.  If  the  soft  soil  is  more  than  40  feet  deep,  piles  varying  from 
15  to  40  feet  in  length  should  be  driven,  according  to  the  character 
of  the  soil,  the  sustaining  power  of  the  piles  depending  upon  the 
friction  between  the  pile  and  the  surrounding  soil. 

3.  Short  piles,  from  10  to  15  feet  in  length,  are  sometimes  driven, 
particularly  in  Southern  cities,  in  order  to  consolidate  the  soil  and  to 
give  it  greater  resisting  power.  As  piles  are  seldom  used  in  this 
way,  this  met*hod  of  forming  a  foundation  bed  will  be  dismissed  with 
the  following  quotation  : 

39.  FOUNDATIONS  ON  SOFT  ALLUVIAL  SOILS.— 'Tn 
some  sections  of  the  country,  especially  in  the  Southern  cities,  the 
soil  is  of  a  soft  alluvial  material,  and  in  its  natural  state  is  not 
capable  of  bearing  heavy  loads.  In  such  cases  trenches  are  dug  as  in 
firm  material,  and  a  single  or  double  row  of  short  piles  are  driven 
close  together,  and  under  towers  or  other  unusually  heavy  portions 
of  the  structure  the  area  thus  covered  is  filled  with  these  piles.  The 
effect  of  this  is  to  compress  and  compact  the  soil  between  the  piles, 
and  to  a  certain  extent  around  and  on  the  outside,  thereby  increas- 
ing its  bearing  power;  whatever  resistance  the  piles  may  offer  to 
further  settlement  mav  be  added,  though  not  relied  upon.  These 
piles  are  then  cut  off  close  to  the  bottom  of  the  trench,  and  generally 
a  plank  flooring  is  laid  resting  on  the  soil  and  piles,  or  a  layer  cf 
sand  or  concrete  is  spread  over  the  bottom  of  the  trench  to  the  depth 
of  6  inches  or  i  foot,  and  the  structure,  whether  of  brick  or  stone, 
commenced  on  this.  There  is  little  or  no  danger  of  such  structures 
settling,  and  if  they  do  the  chances  are  that  they  will  settle  uniformly 
if  the  number  of  piles  are  properly  proportioned  to  the  weight  di- 


PILE  FOUNDATIONS. 


27 


rectly  above  them ;  but  if  the  piles  are  not  so  proportioned  the  same 
number  being  driven  under  a  low  wall  as  under  a  high  wall,  unequal 
settlement  is  liable  to  take  place,  causing  ugly  or  dangerous  cracks 
in  the  structure."* 

A.   WOODEN  PILES 

40.  MATERIAL. — Wooden  piles  are  made  from  the  trunks  of 
trees  and  should  be  as  straight  as  possible,  and  not  less  than  5  inches 
in  diameter  at  the  small  end  for  light  buildings  or  8  inches  for  heavy 
buildings.  The  woods  generally  used  for  piles  in  the  Northern 
States  are  spruce,  hemlock,  white  pine,  Norway  pine,  Georgia  pine, 
and  occasionally  oak,  hickory,  elm,  black-gum  and  basswood.  In  the 
Southern  States,  Georgia  pine  or  pitch  pine,  cypress  and  oak  are 
used.  The  tougher  and  stronger  woods  are  the  best  for  timber  piles, 
especially  where  they  are  to  be  driven  to  hard-pan,  and  heavily 
loaded.  There  is  little  difference  in  the  durability  of  these  various 
woods  under  water.  Oak  is  considered  the  most  durable  wood  for 
piles,  and  also  the  toughest,  but  it  is  too  expensive  for  general  use 
in  the  Northern  States,  besides  being  difficult  to  obtain  in  long, 
straight  pieces.  Next  to  oak  come  Georgia  pine,  Oregon  pine, 
cypress  and  spruce,  in  the  order  named. 

Of  the  1,700  piles  supporting  the  Illinois  Central  Railway  Station 
in  Chicago,  32  per  cent  were  black-gum,  22  per  cent  pine,  7  per  cent 
basswood,  21  per  cent  oak,  15  per  cent  hickory,  with  a  few  maple  and 
elm.  A  smaller  proportion  of  the  hickory  piles  were  broken  or 
crushed  than  of  any  other  wood. 

41.  POINTING  WOODEN  PILES.— Piles  should  be  prepared 
for  driving  by  cutting  off  all  limbs  close  to  the  trunk,  sawing  the 
ends  square,  and  removing  the  bark.  The  removal  of  the  bark  is 
probably  of  not  very  great  importance,  as  many  piles  are  driven  with 
the  bark  on.  The  small  end  of  each  pile  should  be  sharpened  to  a 
point  2  inches  square,  the  bevel  being  from  18  to  24  inches  long. 
The  large  end  should  be  cut  square  to  receive  the  blows  from  the 
hammer. 

Experience  has  shown  that  in  soft  and  silty  soils  the  piles  can  be 
driven  in  better  line  without  pointing.  A  pointed  pile,"  on  striking  a 
root  or  similar  obstruction,  will  inevitably  glance  off,  and  no  avail- 
able power  can  prevent  it  from  doing  so,  while  a  blunt  pile  will  cut 
or  break  the  obstruction  without  being  diverted  from  its  position. 

*  "A  Practical  Treatise  on  Foundations."    W.  M.  Fatten. 


28  BUILDING  CONSTRUCTION.  (Ch.  II) 


When  driving  into  compact  soil,  such  as  sand,  gravel  or  stiff  clay, 
the  point  of  the  pile  is  often  shod  with  iron  or  steel,  either  in  the 
form  of  a  strap  bolted  to  the  end  of  the  pile,  as  at  a,  Fig.  13,  or  by 
a  conical  cast-steel  shoe  about  5  inches  in  diameter,  having  a  134- 


in  diameter  than  the  head  of  the  pile,  and  from  2^  to  3  inches 
wide  by  ^  of  an  inch  thick.  It  is  better  to  chamfer  the  head  so 
that  the  ring  will  just  fit  on  than  to  drive  the  ring  into  the  wood 
by  the  hammer,  as  the  latter  method  is  liable  to  split  long  pieces 
from  the  pile. 

43.  PROTECTION  OF  WOODEN  PILES.— Piles  that  are 
to  be  driven  in,  or  exposed  to,  salt  water  should  be  thoroughly  im- 
pregnated with  creosote,  dead  oil  of  coal-tar,  or  some  mineral 
poison  to  protect  them  from  the  ''teredo"  or  ship  worm,  which  will 
completely  honeycomb  an  ordinary  pile  in  three  or  four  years. 

44.  DRIVING  WOODEN  PILES  WITH  THE  DROP-HAM- 
MER.— The  usual  method  of  driving  piles  is  by  a  succession  of 
blows  given  with  a  block  of  cast-iron  called  the  hammer,  which 
works  up  and  down  between  the  uprights  of  a  frame  or  machine 
called  a  pile-driver.  The  machine  is  placed  over  the  pile,  so  that  the 
hammer  descends  fairly  on  its  head,  the  piles  always  being  driven 
with  the  small  end  down.  The  hammer  is  generally  raised  by  steam 
power  furnished  by  a  hoisting  engine,  and  is  dropped  either  auto- 
matically or  by  hand.    The  usual  weight  of  the  hammers  used  for 


inch  dowel  inches  long  fit- 
tins:  into  a  hole  in  the  end  of 
the  pile  and  a  ring  fitting 
around  the  pile,  as  shown  at 
b,  to  prevent  it  from  splitting. 
The  latter  method  should  be 
used  in  very  hard  soils.  If  a 
strap  is  used,  as  at  a,  it  should 
be  2^  inches  wide,  an 
inch  thick  and  4  feet  long. 


42.  RINGING  WOODEN 
PILES. — When  the  penetra- 


Fig.  13.    Straps  and  Shoes  for  Piles. 


tion  at  each  blow  is  less 
than  6  inches,  the  top  of  the 
pile  should  be  protected  from 
"brooming"  by  putting  on  an 
iron  ring  about  i   inch  less 


PILE  FOUNDATIONS. 


29 


driving  piles  for  building  foundations  is  from  1,500  to  2,500  pounds, 
and  the  fall  varies  from  5  to  20  feet,  the  last  blows  being  given  with 
a  short  fall.  Heavier  hammers  than  these  are  sometimes,  but  not 
often,  used,  occasionally  weighing  4,000  pounds  and  over. 

In  driving  piles  care  should  be  taken  to  keep  them  plumb,  and 
when  the  penetration  becomes  small  the  fall  should  be  reduced  to 
about  5  feet,  the  blows  being  given  in  rapid  succession. 

Whenever  a  pile  refuses  to  sink  under  several  blows,  before  reach- 
ing the  average  depth,  it  should  be  cut  off  and  another  pile  driven 
beside  it. 

When  several  piles  have  been  driven  to  a  depth  of  20  feet  or  more 
and  refuse  to  sink  more  than  ^  an  inch  under  five  blows  of  a  1,200- 
pound  hammer  falling  15  feet,  it  is  useless  to  try  them  further,  as  the 
additional  blows  only  result  in  brooming  and  crushing  the  heads  and 
points  of  the  piles,  and  in  splitting  and  crushing  the  intermediate 
portions  to  an  unknown  extent. 

''Sometimes  piles  drive  easily  and  regularly  to  a  certain  depth,  and 
♦  then  refuse  to  penetrate  farther.  This  may  be  caused  by  a  thin 
stratum  of  some  hard  material,  such  as  cemented  gravel  and  sand  or 
a  compact  marl.  It  may  require  many  hard  and  heavy  blows  to  drive 
through  this,  thereby  injuring  the  piles,  and  perhaps  getting  into  a 
q.uicksand  or  other  soft  material,  when  the  pile  will  drive  easily  again. 
If  the  depth  of  the  overlying  soil  penetrated  is  sufficient  to  give  lat- 
eral stability,  or  if  this  can  be  secured  by  artificial  means,  such  as 
throwing  in  broken  stone  or  gravel,  it  would  seem  unwise  to  endeavor 
to  penetrate  the  hard  stratum,  and  the  driving  should  be  stopped 
after  a  practical  refusal  to  go  with  two  or  three  blows.  The  thick- 
ness of  this  stratum  and  the  nature  of  the  underlying  material 
should  be  determined  either  by  boring  or  by  driving  a  test  pile,  to 
destruction  if  necessary.  In  the  latter  case  the  driving  of  the 
remaining  piles  should  cease  as  soon  as  the  hard  stratum  is 
reached."  * 

If  the  hard  stratum,  however,  is  only  2  or  3  feet  thick,  with 
hard-pan  not  more  than  40  or  50  feet  from  the  surface,  the  piles 
should  be  driven  to  hard-pan  for  heavy  buildings;  but  if  the  soft 
material  continues  for  an  indefinite  depth  below  the  hard  stratum, 
the  piles  should  be  stopped  when  the  stratum  is  reached.  In  such 
cases,  however,  the  actual  bearing  power  of  the  piles  should  be  tested 
by  loading  one  or  more  of  them,  as  described  in  Section  50. 

*  "A  Practical  Treatise  on  Foundations."    W.  M.  Patton. 


30 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


45.  DRIVING  WOODEN  PILES  WITH  THE  STEAM- 
HAMMER.— There  are  two  other  methods  of  driving  piles  com- 
monly employed,  namely :  with  the  steam-hammer,  and  by  the  water- 
jet  process.  By  the  former  method  a  specially  constructed  steam- 
hammer,  in  contact  with  or  attached  to  the  head  of  the  pile,  strikes 
a  rapid  succession  of  blows  which  cause  the  pile  to  penetrate  rapidly, 
because  the  earth  at  the  penetration  point  of  the  pile  is  not  allowed 
time  to  compact  and  readjust  itself  after  each  blow.  The  blows 
struck  are  comparatively  light,  and  the  head  of  the  pile  does  not 
broom  and  break  up  as  much  as  under  the  hammer  of  the  ordinary 
pile-driver.  Because  of  this  the  pile  used  under  a  steam-power  ham- 
mer may  be  of  poorer  quality  and  softer  wood  than  would  ordinarily 
be  used  under  a  drop-hammer,  and  the  pile  in  driving  may  be  kept 
more  easily  in  line. 

46.  DRIVING  WOODEN  PILES  WITH  THE  WATER-JET. 
— Piles  may  be  driven  by  means  of  a  water-jet,  and  sometimes  both 
the  drop-hammer  and  water- jet  are  used  in  conjunction.  In  using 
the  water-jet  for  sinking  piles  a  piece  of  pipe  or  rubber  hose,  from 
1^/2  to  2^  inches  in  diameter,  is  secured  to  the  pile  with  staples  in 
such  a  manner  that  it  may  be  withdrawn  after  the  pile  is  driven.  The 
piece  of  pipe  or  hose  passes  down  to  the  end  of  the  pile,  and  is  con- 
nected at  the  upper  end  with  a  pump  and  provided  at  the  lower  end 
with  a  nozzle,  usually  from  i  inch  to  J/s  of  an  inch  in  diameter. 
Under  operation  the  force  of  the  water  scours  out  and  liquefies  the 
soil  beneath  and  around  the  pile,  so  that  it  sinks  by  its  own  weight 
or  the  weight  of  the  operating  platform  brought  to  bear  upon  it. 

This  method  of  driving  operates  the  best  in  soils  consisting  mostly 
of  sand,  soft  clay  or  mud,  though  it  may  be  used  in  nearly  all  soils 
except  hard-pan  or  rock.  Generally  the  best  results  are  obtained 
by  this  process  when  a  considerable  volume  of  water  is  delivered  at 
a  moderate  velocity,  as  the  rapid  penetration  of  the  pile  depends 
more  upon  the  fluidity  created  in  the  surrounding  soil  than  upon  the 
scouring  action  of  the  jet.  The  water- jet  process  is  much  used  for 
sinking  piles  for  piers,  breakwaters  and  jetties  in  sandy  beaches, 
but  is  not  used  to  such  a  great  extent  for  building  construction  as 
the  amount  of  water  used  is  in  most  instances  objectionable. 

47.  BEARING  POWER  OF  WOODEN  PILES.— When 
driven  in  sand  or  gravel,  or  to  hard-pan,  piles  will  carry  to  the  full 
extent  of  the  crushing  strength  of  the  timber,  providing  their  depth 
is  sufficient  to  secure  lateral  stiffness. 


PILE  FOUNDATIONS. 


''There  are  examples  of  piles  driven  in  stiff  clay  to  the  depth  of  20 
feet  that  carry  from  70  to  80  tons  per  pile.  There  are  many  instances, 
in  which  piles  carry  from  20  to  40  tons  under  the  above  conditions. 
After  a  pile  has  been  driven  to  20  feet  in  sand  or  gravel,  any  further 
hammering  is  a  waste  of  time  and  money,  and  injurious  to  the 
pile  itself."  * 

Piles  driven  from  30  to  40  feet  in  even  the  softest  alluvial  soils 
should  carry  by  frictional  resistance  alone  from  10  to  i2j/4  tons. 


TABLE  II. 

Safe  Bearing  Value  of  Wooden  Piles  in  Different  Soils. 


SOIL. 

PILE 
LENGTHS. 

AVERAGE 
DIAMETER 

PENETRA- 
TION. 

LOAD  IN 
TO.NS. 

Ft. 

Ins. 

Ins. 

40 

10 

6 

Mud  

30 

8 

2 

6 

Soft  earth  with  boulders  or  logs  

30 

8 

li 

7 

Moderately  firm  earth  or  clay  with 

30 

8 

I 

9 

30 

10 

I 

9 

30 

8 

1 

12 

30 

8 

1 

12 

20 

8 

1 

4 

14 

20 

8 

0 

20 

20 

8 

0 

20 

15 

8 

0 

20 

The  bearing  value  of  a  pile  depends  upon  the  distance  which 
it  penetrates  the  soil  under  the  final  blows  of  the  hammer;  so  that, 
when  this  distance  is  known,  together  with  the  weight  and  the  height 
of  fall  of  the  hammer,  the  probable  bearing  value  of  the  pile  may  be 
determined.  The  values  given  in  Table  II,  which  follows,  show  the 
probable  penetration  of  piles  of  different  lengths  when  driven  into  the 
different  kinds  of  soil  usually  encountered.  The  safe  bearing  values 
in  tons,  given  in  the  last  column  of  the  table,  are  calculated  from 
the  Engineering  Nezvs  formula,  which  is  explained  in  the  follow- 
ing article.  The  values  given  in  the  table  are  for  minimum  lengths 
of  spruce  piles  and  average  penetrations  for  the  last  five  blows  of  a 
1,200-pound  hammer  falling  15  feet.  When  heavier  loads  than 
these  must  be  carried,  or  when  the  penetration  is  much  greater,  the 
actual  bearing  power  of  the  piles  should  be  determined  by  testing, 
unless  it  is  already  known  from  actual  experience. 


'A  Practical  Treatise  on  Foundations."    W.  M.  Patton. 


32 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


48.  FORMULA  FOR  THE  SAFE  WORKING  LOAD  ON 
PILES. — There  have  been  several  formulas  proposed  for  determin- 
ing the  safe  working  loads  on  piles.  Of  these,  one  of  the  latest, 
know^n  as  the  Engineering  Nezvs  formula,  is  generally  considered  to 
be  the  most  reliable.  It  is  claimed  for  this  formula  that  it  sets  "a 
definite  limit,  high  enough  for  all  ordinary  economic  requirements, 
up  to  which  there  is  no  record  of  pile  failures,  excepting  one  or  two 
dubious  cases  where  a  hidden  stratum  of  bad  material  lay  beneath  the 
pile,  and  above  which  there  are  instances  of  both  excess  and  failure, 
with  an  increasing  proportion  of  failures  as  the  limit  is  exceeded." 

The  formula  is : 

2  iif  h 


Safe  load  in  lbs. 


(I) 


^  + 1 

in  which  iv  =  the  weight  of  hammer  in  pounds ;  h,  its  fall  in  feet ; 
and  s,  the  average  set  under  the  last  blows  in  inches. 

For  convenience  the  following  table  is  given  which  shows  the 
allowable  or  safe  bearing  values  for  piles,  calculated  from  the  above 
formula,  for  different  penetrations  under  the  blows  of  a  2,000-pound 
hammer  falling  from  3  to  30  feet. 


TABLE  III. 

Safe  Load,  in  Tons,  for  Wooden  Piles. 

(Hammer  weighing  one  ton.) 


Penetra- 

Drop of  the 

Hammer,  in  Feet. 

tion  of 

Pile  in 

Inches. 

3 

4 

5 

6 

,  8 

10 

12 

14 

16 

18 

20 

25 

30 

0.25 

4.8 

6.4 

8.1 

9.7 

12.9 

16.1 

19.4 

22.5 

25.8 

29.1 

32.3 

0.50 

4.0 

5.3 

6.7 

8.0 

10.7 

13.3 

16.1 

18.7 

21.3 

24.0 

26.6 

33 .3 

0.75 

3.4 

4.6 

5.7 

6.9 

9.2 

11.5 

13.8 

16.1 

18.4 

20.7 

23.0 

28.8 

34 '5 

1.00 

3.0 

4.0 

5.0 

6.0 

8.0 

10.0 

12.0 

14.0 

16.0 

18  0 

20.0 

25.0 

30.0 

1.25 

3.6 

4.5 

5.4 

7.1 

8.9 

10.7 

12.5 

14.3 

16.1 

17.9 

22.3 

26.7 

1.50 

3.2 

4.0 

4.8 

6.4 

8.0 

9.6 

11.2 

12.8 

14.4 

16.0 

20.0 

24.0 

1.75 

3.G 

4.4 

5.8 

7.3 

8.8 

10.2 

11.7 

13.1 

14.6 

18.2 

21.9 

2.00 

3.3 

4.0 

5.3 

6.7 

8.0 

9.3 

10.7 

12.0 

13.3 

16.7 

20.0 

2.50 

3.4 

4.6 

5.7 

6.9 

8.0 

9.1 

10.3 

11.4 

14.3 

17.1 

3.00 

3.0 

4.0 

5.0 

6.0 

7.0 

8.0 

9.0 

10.0 

12.5 

15.0 

3.50 

3.6 

4.4 

5.3 

6.2 

7.1 

8.0 

8.9 

11.1 

13.3 

4.00 

3.2 

4.0 

4.8 

5.6 

6.4 

7.2 

8.0 

10.0 

12.0 

5.00 

3.3 

4.0 

4.7 

5.3 

6.0 

6.7 

8.3 

10.0 

6.00 

3,4 

4.0 

4.6 

5.1 

5.7 

7.1 

8.6 

As  the  values  in  the  above  table  vary  directly  with  the  weight  of 
the  hammer,  if  the  penetration  is  caused  by  a  1,000-pound  hammer, 
the  bearing  value  will  be  one-half  of  that  given,  and  in  this  way  the 
table  may  be  used  to  obtain  the  bearing  value  of  piles  driven  by  a 
hammer  of  any  weight. 


PILE  FOUNDATIONS. 


33 


49.  MUNICIPAL  REGULATIONS  REGARDING  WOODEN 
PILES. — The  New  York  Building  Law,  1906,  provides  that 
''Piers  intended  to  sustain  a  wall,  pier  or  post  shall  be  spaced  not  more  than 
36  nor  less  than  20  inches  on  centers,  and  they  shall  be  driven  to  a  solid 
bearing,  if  practicable  to  do  so,  and  the  number  of  such  piers  shall  be  suffi- 
cient to  support  the  superstructure  proposed. 

"No  pile  shall  be  used  of  less  dimensions  that  5  inches  at  the  small  end 
and  10  inches  at  the  butt  for  short  piles,  or  piles  20  feet  or  less  in  length,  and 
20  inches  at  the  butt  for  long  piles,  or  piles  more  than  20  feet  in  length. 

"No  pile  shall  be  weighted  with  a  load  exceeding  40,000  pounds. 

'The  tops  of  all  piles  shall  be  cut  off  below  the  lowest  water  line.  When 
required,  concrete  shall  be  rammed  down  in  the  interspaces  between  the  heads 
of  the  piles  to  a  depth  and  thickness  of  not  less  than  12  inches  and  for  i  foot 
in  width  outside  of  the  piles." 

The  Boston  Building  Law,  1907,  requires  that 
''All  buildings  shall,  if  the  commissioner  determines  that  piling  is  necessary, 
be  constructed  on  foundation  piles  which,  if  of  wood,  shall  be  not  more  than 
3  feet  apart  on  centers  in  the  direction  of  the  wall,  and  the  number,  diameter 
and  bearing  of  such  piles  shall  be  sufficient  to  support  the  superstructure 
proposed.  The  commissioner  shall  determine  the  grade  at  which  the  piles 
shall  be  cut. 

"All  wood  piles  shall  be  capped  with  block  granite  levellers,  each  leveller 
having  a  firm  bearing  on  the  pile  or  piles  which  it  covers,  or  with  first-class 
Portland  cement  concrete  not  less  than  16  inches  thick,  above  the  pile  caps, 
containing  i  part  of  cement  to  not  more  than  6  parts  of  properly  graded 
aggregate  of  stone  and  sand,  the  concrete  to  be  filled  in  around  the  pile  heads 
upon  the  intervening  earth." 

In  the  Chicago  Building  Law,  1906,  it  is  required  that 

"The  piles  shall  be  made  long  enough  to  sustain  the  required  load  according 
to  approved  formulas  for  pile  driving,  and  timber  piles  shall  not  be  loaded 
more  than  25  tons  to  each  pile." 

The  Philadelphia  Bureau  of  Building  Inspection  stipulates  that 
"Piles  intended  for  a  wall,  pier  or  post  to  rest  upon,  shall  not  be  less  than  5 
inches  in  diameter  at  the  small  end,  and  shall  be  spaced  not  more  than  30 
inches  on  centers,  or  nearer  if  required  by  the  Bureau  of  Building  Inspection, 
and  they  shall  be^  driven  to  a  solid  bearing.  No  pile  shall  be  weighted  with  a 
load  exceeding  40,000  pounds.  The  tops  of  all  piles  shall  be  cut  off  below 
the  lowest  v^ater  line  where  required ;  concrete  shall  be  rammed  down  in  the 
interstices  between  the  heads  of  the  piles  to  the  depth  and  thickness  of  at  least 
12  inches,  and  for  i  foot  in  width  outside  of  the  pile.  When  ranging  and 
capping  timbers  are  laid  on  piles  for  foundations  they  shall  be  of  hard  wood  t 
not  less  than  6  inches  thick,  and  properly  joined,  and  their  tops  laid  below 
the  lowest  water  line." 

General  William  Sooy  Smith,  in  an  address  delivered  March  31. 
1892,  before  the  students  of  engineering  of  the  University  of  Illinois^ 


34 


BUILDING  CONSTRUCTION.  (Ch.  II) 


stated  that  "A  pile  at  the  bottom  of  a  pit  30  feet  deep  and  well  into 
hard-pan,  or  to  the  rock  where  this  is  within  reach,  can  be  safely 
relied  upon  to  sustain  from  30  to  40  gross  tons." 

50.  EXPERIMENTS  ON  THE  BEARING  POWER  OF 
WOODEN  PILES. — The  following  description  of  several  tests 
made  to  determine  the  actual  sustaining  power  of  piles  in  various 
localities  gives  a  good  idea  of  the  manner  of  making  such  tests,  as 
well  as  of  the  loads  required  to  sink  the  piles : 

CHICAGO  PUBLIC  LIBRARY.— To  determine  the  actual  resistance  of 
the  piles  on  which  it  was  proposed  to  erect  the  Public  Library  building  in 
Chicago,  the  following  test  was  made:  In  order  to  make  the  experiment 
under  the  same  conditions  as  would  exist  under  the  structure  three  rows  of 
piles  were  driven  into  the  trench,  the  piles  in  the  middle  row  being  then  cut 
off  below  the  level  at  which  those  in  the  outside  row  were  cut  off,  so  as  to 
bring  the  bearing  only  on  four  piles,  two  in  each  outside  row.  This  gave  the 
benefit  arising  from  the  consolidation  of  the  material  by  the  other  piles.  The 
piles  were  of  Norway  pine,  54  feet  long,  and  were  driven  about  52^/2  feet, 
27  feet  in  soft,  plastic  clay,  23  feet  in  tough,  compact  clay  and  2  feet  in  hard- 
pan.  They  had  an  average  diameter  of  13  inches  and  an  area  at  the  small  end 
of  80  square  inches. 

On  top  of  the  four  outside  piles,  which  were  spaced  5  feet  apart  on  centers, 
15-inch  steel  I-beams  were  placed,  and  upon  these  a  platform,  7  by  7  feet,  com- 
posed of  12  by  12-inch  yellow  pine  timbers.  On  this  platform  pig-iron  was  piled 
up  at  irregular  intervals.  When  4  feet  high  the  load  was  45,200  pounds,  and 
was  then  continued,  until  at  the  end  of  about  four  days  it  was  21  feet  high, 
giving  a  load  of  224,500  pounds.  Levels  were  taken,  but  no  settlement  had 
occurred.  By  the  end  of  about  eleven  days  the  pile  of  iron  had  reached  the 
height  of  38  feet,  giving  a  load  of  404,800  pounds  upon  the  four  piles,  or  about 
50.7  tons  per  pile.  Levels  were  then  taken  at  intervals  during  a  period  of  about 
two  weeks,  and,  no  settlement  having  been  observed,  a  load  of  30  tons  was 
considered  perfectly  safe. 

PERTH  AMBOY,  N.  J.,  1873.— Pretty  fair  mud,  30  feet  deep.  Four  piles, 
12,  14,  16  and  18  inches  diameter  at  top,  6  to  8  inches  at  foot,  were  driven  in  a 
square  to  depths  of  from  33  to  35  feet.  A  platform  was  built  upon  the  heads 
of  the  piles  and  loaded  with  179,200  pounds,  or  44,800  pounds  per  pile.  After 
a  few  days  the  loads  were  removed.  The  18-inch  pile  had  not  moved,  the 
12-inch  pile  had  settled  3  inches,  and  the  14  and  15-inch  piles  had  settled 
to  a  less  extent.* 

BUFFALO,  N.  Y. — In  the  construction  of  a  foundation  for  an  elevator  at 
Buffalo,  N.  Y.,  a  pile  15  inches  in  diameter  at  the  large  end,  driven  18  feet, 
bore  25  tons  for  twenty-seven  hours  without  any  ascertainable  effect.  The 
weight  was  then  gradually  increased  until  the  total  load  on  the  pile  was  37^ 
tons.  Up  to  this  weight  there  had  been  no  depression  of  the  pile,  but  with 
37J/^  tons  there  was  a  gradual  depression  which  aggregated  Y%  of  an  inch, 
beyond  which  there  was  no  depression  until  the  weight  was  increased  to  50 

*  "A  Practical  Treatise  on  Foundations."    W.  M.  Fatten. 


PILE  FOUNDATIONS.  35 

tons.  With  50  tons  there  was  a  further  depression  of  %  of  an  inch,  making 
the  total  depression  lYz  inches.  Then  the  load  was  increased  to  75  tons, 
under  which  the  total  depression  reached  3^  inches.  The  experiment  was 
not  carried  beyond  this  point.   The  soil,  in  order  from  the  top,  was  as  follows : 

2  feet  of  blue  clay,  3  feet  of  gravel,  5  feet  of  stiff  red  clay,  2  feet  of  quicksand, 

3  feet  of  red  clay,  2  feet  of  gravel  and  sand  and  3  feet  of  very  stiff  blue  clay. 
AH  the  time  during  this  experiment  there  were  three  pile-drivers  at  work  on 
the  foundation,  thus  keeping  up  a  tremor  in  the  ground.  The  water  from 
Lake  Erie  had  free  access  to  the  pile  through  the  gravel.  * 

"Subsequent  use  shows  that  74,000  pounds  is  a  safe  load." — W.  M.  Patton. 

PHILADELPHIA.— At  Philadelphia  in  1873  a  pile  was  driven  15  feet 
into  soft  river  mud,  and  five  hours  after  7.3  tons  caused  a  sinking  of  a  very 
small  fraction  of  an  inch ;  under  9  tons  it  sank  >>4  of  an  inch  and  under  15 
tons  it  sank  5  feet. 

"The  South  Street,  Philadelphia,  bridge  approach  fell  by  the  sinking  of 
the  foundation  piles  under  a  load  of  24  tons  each.  They  were  driven  to  an 
absolute  stoppage  by  a  i-ton  hammer  falling  32  feet.  Their  length  was  from 
24  to  41  feet.  The  piles  were  driven  through  mud,  tough  clay,  and  then  into 
hard  gravel. "t 

The  failure  in  this  case  may  have  been  caused  by  vibrations  which 
allowed  the  water  to  work  its  way  down  the  sides  of  the  piles  and  thus 
decrease  the  friction ;  or,  what  is  more  probable,  the  last  blow  may  have 
struck  on  a  broomed  head,  which  would  have  greatly  reduced  the  penetration 
and  caused  the  bearing  power  to  be  overestimated. 

When  the  penetration  is  very  slight  or  unobservable,  and  the  head 
much  broomed,  the  broomed  portion  should  be  cut  ofif  and  the  blows 
repeated  if  the  full  load  indicated  by  the  formula  is  to  be  put  on 
the  piles. 

51.  ACTUAL  LOADS  ON  WOODEN  PILES.— The  following 
examples  of  the  actual  loads  which  are  carried  by  each  pile  under 
the  buildings  named  will  serve  as  a  guide  to  architects  erecting 
buildings  in  these  localities : 

BOSTON. — Under  Trinity  Church,  2  tons  each. 

CHICAGO. — Public  Library  building,  30  tons  each. 

Schiller  building,  estimated  load  55  tons  per  pile;  building  settled  from 
to  2^  inches. 

Passenger  Station,  Northern  Pacific  Railroad,  Harrison  Street:  piles  50 
feet  long  carry  25  tons  each  without  perceptible  settlement. 

The  enormous  grain  elevators  in  Chicago  rest  upon  pile  foundations. 
Mr.  Adler  stated  that  the  unequal  and  constantly  shifting  loads  are  a  severer 
test  upon  the  foundations  than  a  static  load  of  a  twenty-story  building. 

NEW  ORLEANS. — Piles  driven  from  25  to  40  feet  in  a  soft,  alluvial 


*  "Masonry  Construction."    Ira  O.  Baker, 
t  Trans.  Am.  Soc.  of  C.  E.,  Vol.  VII.,  p.  264. 


3^^ 


BUILDING  CONSTRUCTION.  (Ch.  II) 


soil  carry  safely  from  15  to  25  tons,  with  a  factor  of  safety  of  6  to  8. — W.  M. 
Patton. 

52.  SPACING  OF  WOODEN  PILES.— Wooden  piles  should 
be  spaced  not  less  than  2  feet  on  centers,  nor  more  than  3  feet  on 
centers,  unless  iron  or  wooden  grillage  is  used. 

When  long  piles  are  driven  closer  together  than  2  feet  on  centers 
there  is  danger  that  they  may  force  each  other  up  from  their  solid 
bed  on  the  bearing  straturn.  Driving  the  piles  close  together  also 
breaks  up  the  ground  and  diminishes  the  bearing  power. 

When  three  rows  of  piles  are  used  the  most  satisfactory  spacing 
is  2  feet  6  inches  on  centers  across  the  trench,  and  3  feet  on  centers 
longitudinally,  provided  this  number  of  piles  will  carry  the  weight 
of  the  building.  If  they  will  not,  then  the  piles  must  be  spaced 
closer  together  longitudinall}-,  or  another  row  of  piles  driven ;  but  in 
no  case  should  two  piles  be  driven  closer  together  than  2  feet  on 
centers,  unless  driven  by  means  of  a  water-jet. 

In  all  cases,  the  number  of  piles  under  the  different  portions  of  a 
l^uilding  should  be  carefully  proportioned  to  the  weight  which  they 
have  to  carry,  so  that  every  pile  will  support  very  nearly  the  same 
load.  This  precaution  is  of  especial  importance  when  some  of  the 
piles  must  be  loaded  to  their  full  capacity. 

53.  CUTTING  OFF  AND  CAPPING  WOODEN  PILES.— 
The  tops  of  the  piles  should  invariably  be  cut  off  below  the  low- 
water  mark,  as  otherwise  they  will  soon  commence  to  decay. 

The  piles  are  generally  cut  off  with  a  large  cross-cut  saw  worked 
by  two  men.  Their  tops  should  be  left  true  and  level  and  on  a  line 
with  each  other.  A  variation  of  >4  of  an  inch  in  the.  tops  of  the 
piles  may  be  allowed,  but  it  should  not  exceed  this  limit. 

Three  methods  of  capping  wooden  piles  are  commonly  employed, 
using  the  following  materials:  i.  Granite  blocks.  2.  Concrete. 
3.  Timber  or  steel-beam  grillage. 

54.  GRANITE  CAPPING  FOR  WOODEN  PILES.— In  this 
method  the  piles  are  capped  with  blocks  of  granite,  which  rest  di- 
rectly on  the  tops  of  the  piles.  If  the  stone  does  not  fit  the  surface  of 
a  pile,  or  a  pile  is  a  little  low,  it  is  wedged  up  with  oak  or  stone 
wedges.  In  capping  with  stone  a  section  of  the  foundation  should 
be  laid  out  on  the  drawings  showing  the  arrangement  of  the  cap- 
ping stones. 

A  single  stone  may  rest  on  one,  two  or  three  piles,  but  should  not 
rest  on  four  piles,  as  it  is  practically  impossible  to  make  the  stone 


PILE  FOUXDATIOXS. 


37 


bear  evenly  on  four  piles.  Fig.  14  shows  the  best  arrangement  of 
the  capping  for  three  rows  of  piles.  Under  dwellings  and  light 
buildings  the  piles  are  often  spaced  as  in  Fig.  15,  in  which  case  each 
stone  should  rest  on  three  piles.  After  the  piles  are  capped  large 
footing  stones,  extending  in  one  piece  across  the  wall,  should  be 
laid  in  cement  mortar,  as  shown  in  Fig  .16. 


'<  ■  

.  1 

— -5— _J 

r  r^— ^ 

\  ) 

I  1  /     ''1  } 

Fig.     14.     Stone  Capping 
Three    Rows    of  Piles. 


for 


Fig.     15.  Stone 
Capping  for  Piles 
Under  Light 
Builditigs. 


Fig.  16.    Stone  Capping  and 
Wall  Footing   on  Piles. 


55.  CONCRETE  CAPPING  FOR  WOODEN  PILES.— In 
New  York  a  very  common  method  of  capping  the  piles  is  to  excavate 
to  a  depth  of  i  foot  below  the  tops  of  the  piles  and  i  foot  outside 
of  them,  and  to  fill  solid  the  space  thus  excavated'  with  rich  Port- 
land cement  concrete,  deposited  in  layers  and  well  rammed.  After 
the  concrete  is  brought  up  level  with  the  tops  of  the  piles,  additional 
layers  of  concrete  are  laid  over  the  whole  foundation  until  it  reaches 
a  depth  of  18  inches  above  the  piles.  On  this  foundation  bed,  the 
brick  or  stone  footings  are  laid  as  on  solid  earth.  Many  engineers 
consider  this  the  best  method  of  capping.  There  is  certainly  no 
question  of  its  durability,  and  it  is  believed  that  the  concrete  will 
preserve  the  heads  of  the  piles  from  rotting,  provided  the  water  is  at 


38 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


all  times  up  to  the  bottom  of  the  concrete.  A  concrete  beam  i8 
inches  thick  would  also  serve  to  distribute  the  pressure  over  the 
piles  tetter  than  the  stone  capping,  although  not  to  such  an  extent 
as  heavy  grillage.  If  the  soil  is  at  all  firm  under  the  concrete, 
it  will  also  assist  the  piles  in  carrying  the  load  when  concrete  cap- 
ping is  used.  Under  very  heavy  buildings  the  space  between  the 
''-piles  to  the  depth  of  i  foot  should  be  filled  with  concrete,  \v  hatever 
kind  of  capping  is  employed. 

Concrete  cappings  in  which  steel  rods  or  bars  are  imbedded  about 
3  inches  above  the  tops  of  the  piles  are  excellent  forms  of  capping 
construction,  the  metal  bars  giving  great  transverse  strength  to  the 
concrete. 

56.  GRILLAGE  CAPPING  FOR  WOODEN  PILES.— In  Chi- 
cago most  of  the  buildings  on  pile  foundations  have  heavy  timber 
grillage  bolted  to  the  tops  of  the  piles,  and  on  these  timbers  are  laid 
the  stone  or  concrete  footings.  For  building  foundations  the  grill- 
age usually  consists  of  12  by  12-inch  timbers  of  the  strongest  woods 
available,  laid  longitudinally  on  top  of  the  piles,  and  fastened  to 
them  by  means  of  drift-holts,  which  are  plain  bars  of  iron,  either 
round  or  square,  driven  into  holes  about  20  per  cent  smaller  in  cross- 
section  than  that  of  a  bolt.  One-inch  round  or  square  bars  are  gen- 
erally used,  each  hole  being  bored  by  a  ^-inch  auger  for  a  round 
bolt,  or  by  a  %-inch  auger  for  a  square  bolt.  The  bolts  should 
enter  the  piles  at  least  i  foot. 

If  heavy  stone  or  concrete  footings  are  used,  and  if  the  space 
between  the  piles  and  the  timbers  is  filled  with  concrete  brought  up 
level  with  the  top  of  the  timbers,  no  more  timbering  is  required ; 
but  if  the  footings  are  made  of  small  stones,  and  if  no  concrete  is 
used,  a  solid  floor  of  cross  timbers,  at  least  6  inches  thick  for  heavy 
buildings,  should  be  laid  on  top  of  the  longitudinal  cappings  and 
drift-bolted  to  them. 

.  Where  timber  grillage  is  used,  it  should,  of  course,  be  kept 
entirely  below  the  lowest  recorded  water  line,  as  otherwise  it  will 
rot  and  allow  the  building  to  settle.  It  has  been  proved  conclu- 
sively, however,  that  any  kind  of  sound  timber  will  last  practically 
forever  if  completely  immersed  in  water. 

The  advantages  of  timber  grillage  are  that  the  timbers  are  easily 
laid  and  efifectually  hold  the  tops  of  the  piles  in  place.  It  also  tends 
to  distribute  the  pressure  evenly  over  the  piles,  as  the  transverse 


PILE  FOUNDATIOXS. 


'39 


strength  of  the  timber  assists  in  carrying  the  load  over  any  single 
pile,  which  for  some  reason  may  not  have  the  same  bearing  capacity 
as  the  others. 

Steel-Beam  Grillage  for  Wooden  Piles. — Steel  beams,  imbedded  in 
concrete,  are  sometimes  used  to  distribute  the  weight  over  piles,  but 
some  other  form  of  construction  can  generally  be  employed  at  less, 
expense  and  with  equally  good  results. 

57.  COST  OF  WOODEN  PILES.— The  cost  of  wooden  piles 
varies  with  the  locality,  size  of  piles  and  difficulties  encountered  in 
driving.  Wooden  piles  of  good  quality  and  average  size,  say  10 
inches  average  diameter  and  from  15  to  25  feet  in  length,  can  be 
driven  for  from  20  to  25  cents  per  foot  of  length,  this  price  includ- 
ing the  cost  of  the  timber  and  driving.  The  variation  from  these 
prices  may  be  as  much  as  25  per  cent  either  way,  and  where  only  a 
few  piles  are  to  be  driven,  the  cost  will  greatly  exceed  the  maximum 
here  given. 

B.    CONCRETE  PILES 

58.  CONCRETE  PILES  COMPARED  WITH  WOODEN 
PILES  AND  CONCRETE  PIERS.— Piles  made  of  concrete  have 
been  used  in  this  country  since  1902,  and  they  offer  several  advan- 
tages over  wooden  piles.  They  remain  practically  uninjured  after 
the  operation  of  driving,  they  do  not  decay,  and  it  is  not  necessary 
to  keep  them  constantly  under  water  to  preserve  them,  as  it  is  in  the 
case  of  wooden  piles.  Consequently,  concrete  piles  can  be  often 
used  to  advantage  in  place  of  wooden  piles,  and  frequently  may  be 
put  in  at  a  lower  cost  than  that  of  spread-footing  construction. 
They  do  not,  as  a  rule,  require  as  thick  a  capping  as  that  required 
for  wooden  piles,  because  they  are  more  readily  incorporated  with 
the  concrete  or  masonry  of  the  capping,  and  not  so  many  of  them 
are  required,  because  they  sustain  a  greater  load  than  wooden  piles 
bear,  under  similar  conditions. 

In  Fig.  17  a  comparison  is  drawn  between  the  method  of  using 
concrete  piles  and  the  method  of  penetrating  a  soft  soil  by  means  of 
wooden  sheet  piling  and  a  concrete  pier.  It  is  frequently  found  in 
cases  of  this  kind  that  the  concrete  piles  are  cheaper  than  the  con- 
crete pier. 

Another  illustration  showing  some  of  the  advantages  gained  by 
the  use  of  concrete  piles  is  given  in  Fig.  18,  (a)  and  (b).  In  figure 
(b)  the  wooden  piles  are  shown  driven  deep  enough  to  be  below  the 


BUILDING  CONSTRUCTION. 


(Ch. 


^80  Tons.  ^eo  Tons. 


Fig.  17.    Concrete  Piles  and  Concrete  Piers  Compared. 


PILE  FOUNDATIONS. 


•41 


low-water  level.  This  necessitates  a  deep  foundation  wall ;  and  as  the 
wooden  piles  will  not  sustain  as  great  a  load  as  the  concrete  piles,  a 
greater  number  of  them  is  required,  with  a  correspondingly  ex- 


Fig.   18.    Concrete  Piles  and  Wooden  Piles  Compared. 


tended  footing.  Figure  (a)  shows  the  foundation  of  the  same 
building  constructed  on  concrete  piles  with  much  less  excavating, 
and  with  probably  greater  permanency. 

Several  types  of  concrete  piles  are  used,  varying  in  details  of  con- 
struction and  in  manner  of  driving,  and  among  them  may  be  men- 
tioned the  "Raymond,"  the  ''Simplex"  and  the  "Corrugated." 


42  BUILDING  CONSTRUCTION.  (Ch.  II) 


59.  THE  RAYMOND  CONCRETE  PILE.— This  concrete  pile 
is  made  by  driving  a  collapsible  steel  core,  around  which  is  a  sec- 
tional tank-steel  shell,  the  sections  being  conical, 
and  fitting  closely  one  within  the  other.  When 
this  core  with  its  outside  shell  has  been  driven 
to  the  required  depth,  the  core  is  partially  col- 
lapsed, released  from  the  sectional  steel  shell, 
and  withdrawn.  In  this  manner  a  sheet-steel- 
lined  form  or  mold  is  made  in  the  ground  for 
casting  the  pile,  the  lining  acting  in  the  same 
manner  as  a  caisson  in  holding  back  the  earth, 
and   in   preventing   the   partial   filling   of  the 


Fig.   19.    The  Raymond  Concrete  Pile. 


form  by  loose  particles,  or  its  destruction  by  any  pressure  on  the 
surrounding  soft  stratum.  After  the  mold  is  thus  formed  it  is 
filled  with  a  good  mixture  of  concrete,  which  is  carefully  tamped 
during  the  process  of  filling. 

Sometimes  these  piles  are  reinforced  to  increase  their  strength,  or 
to  provide  anchorage  for  stacks  or  tower  foundations  subjected  to 


PILE  FOUNDATIONS. 


43 


wind-pressure.    Such  reinforcement  is  easily  put  in  place  during" 
the  process  of  filling.    The  form  of  the  ''Raymond"  concrete  pile 
and  a  diagrammatical  representation  of  the  method  of  driving  the 
cone  and  shell  is  shown  in  Fig.  19,  (a)  and  (b).  • 
60.    THE  SIMPLEX  CONCRETE  PILE.— This  concrete  pile. 


Fig.  20.    The  Simplex  Concrete  Pile. 


like  the  ''Raymond,"  is  made  in  the  ground  and  not  driven.  The 
form  of  the  pile  differs  from  the  "Raymond,"  the  sides  being  par- 
allel instead  of  tapering,  and  when  finished  there  is  no  surrounding 
steel  cylinder. 

The  construction  of  the  "Simplex"  pile  is  shown  in  Fig.  20,  (a) 
and  (b).  At  (a)  is  shown  an  extra  heavy  steel  pipe  about  16  inches 
in  diameter,  driven  into  the  ground.  At  the  end  of  the  pipe  there 
is  a  penetration-shoe  of  cast-iron  used  to  prevent  the  earth  from 


BUILDING  CONSTRUCTION.  (Ch.  II) 


filling  the  pipe  while  it  is  being  driven.  When  the  steel  cylinder 
reaches  the  required  depth  and  rests  upon  hard-pan  or  penetrates 
hard  gravel,  it  is  filled  with  concrete  as  the  steel  driving  form  is 
partly  withdrawn,  and  the  penetration-shoe  is  released  and  left  in 
the  ground.  The  weight  of  the  concrete  causes  it  to  flow  out  at  the 
lower  end  of  the  pipe  or  driving  form  and  completely  fill  the  hole  in 
the  soil. 

A  second  method  of  forming  the  pile  consists  in  providing  an 
"alligator-jaw"  or  hinged  point  at  the  end  of  the  cylinder,  instead 
of  a  cast-iron  penetration-shoe.  This  is  shown  at  (b).  This  jaw  is 
opened  to  the  full  extent  of  the  form  when  the  cylinder  is  with- 
drawn, allowing  the  concrete  to  flow  into  the  hole. 

As  the  hole  formed  by  the  pipe  is  not  lined  with  sheet-metal  there 
is  a.  possibility  of  some  soft  earth  pressing  in  upon  the  concrete 
before  it  has  set,  thus  preventing  a  uniformity  of  cross-sections. 
This  has  not  proved  a  serious  trouble,  however. 

Concrete  piles  are  sometimes  used  in  conjunction  with  timber 
piles,  and  when  so  employed  are  called  "composite  piles."  These 
piles  are  used  for  driving  to  a  great  depth  in  comparatively  soft 
soil.  The  concrete  pile  caps  the  timber  pile  and  forms  an  extension 
to  it  from  below  the  low-water  line,  and  it  is  said  to  afford  a  cheaper 
construction  under  some  conditions  than  longer  piles  made  entirely 
of  concrete. 

6i.  THE  CORRUGATED  CONCRETE  PILE.— There  are 
several  reinforced  concrete  piles  in  use,  which  are  first  molded  to 
the  required  shape,  and  when  the  concrete  has  set  sufficiently,  are 
driven  by  a  hammer,  a  water-jet,  or  a  combination  of  both  methods, 
in  much  the  same  manner  as  wooden  piles  are  driven,  about  the  only 
difference  being  the  special  "driving  head"  provided  to  avoid  the 
shock  of  the  hammer. 
A  section  through  what  is  known  as  the  "Corrugated  Concrete 
Pile"  is  shown  in  Fig.  21.  This  particular 
form  of  concrete  pile  is  made  with  a  vertically 
corrugated  surface,  and  with  a  hole  left  ver- 
tically through  the  axis  of  the  pile.  It  is 
driven  by  using  the  water- jet  and  hammer 
together.  A  hose,  or  pipe,  with  water  under 
pressure,  is  passed  down  through  the  hole  in 
Concrete  p'iie?'"'''^  the  middle  of  the  pile  while  it  is  in  the  machine. 


PILE  FOUNDATIONS. 


45 

it 


The  force  of  the  water  at  the  lower  end  loosens  the  earth  and  drives 
it  up  along  the  corrugations,  and  the  pile  settles  under  the  blows 
of  the  hammer  on  its  cushioned  head.  In  one  instance  it  was  found 
that  after  the  concrete  had  had  eight  days  to  set,  the  piles  were 
not  damaged  in  any  way  at  their  upper  ends  by  the  action  of  the 
hammer. 

These  corrugated  concrete  piles  are  reinforced  with  ''Clinton" 
electrically  welded  wire  fabric,  consisting  generally  of  ^  inch  wires^ 
3  inches  on  centers  longitudinally,  and  ]4,  inch  wires  12  inch  on 
centers  around  the  pile. 

62.  THE  COMPRESSOL  SYSTEM.— There  is  another  kind 
of  construction  which  may  be  classified  with  the  other  types  of  con- 
crete pile  construction,  and  that  is  the  "Compressol  System  of  Foun- 
dation Construction."  In  this  system  the  ground  is  mechanically 
perforated  by  dropping  a  pointed  weight  very  similar  in  form  to  an 
enlarged  plumb-bob.  This  pointed  weight,  dropped  rapidly,  perfo- 
rates the  ground  and  compresses  it  vertically  and  laterally,  and  the 
hole  so  formed  is  filled  with  concrete.  The  latter  is  thoroughly 
tamped,  and  forms  a  pillar  strong  enough  to  carry  from  60  to  90 
tons,  according  to  the  nature  and  depth  of  the  soil.  The  piers  of 
concrete  so  formed  are  capped  with  concrete  in  a  manner  similar  to 
that  of  capping  concrete  piles. 

The  method  used  in  constructing  these  piers  or  cores  in  the  earth 
is  shown  in  Fig.  22.  The  weight  drops  and  perforates  the  soil,  the 
hole  usually  going  down  to  hard-pan.  The  falling  of  the  weight 
compresses  the  soil  on  each  side  of  the  hole  and  prevents  the  per- 
colation of  water  into  it.  Sometimes  the  hole  can  be  lined  with 
puddle  or  clay  by  inserting  some  of  this  material  under  the  perforat- 
ing hammer  and  allowing  it  to  be  carried  down  to  line  the  hole. 
When  the  ground  has  been  perforated  as  described,  a  coarse  con- 
crete is  tamped  into  the  bottom  of  the  hole,  and  a  hammer  shaped 
as  shown  in  the  figure  is  dropped,  striking  successive  blows  as  the 
hole  is  filled.  In  this  manner  the  concrete  is  forced  and  tamped 
compactly  into  the  hole,  and  spread  out  at  the  bottom  as  indicated 
in  the  figure  at  (b)  ;  so  that  if  the  earth  were  excavated  from 
around  the  concrete  pier,  the  latter  would  appear  as  shown  in 
Fig.  23. 

The  following  are  some  of  the  advantages  claimed  for  this  system 
of  foundation  construction :    Pillars  of  concrete  can  be  formed  to 


BUILDING  COXSTRUCTION.  (Ch.  II) 


PILE  FOUXDATIONS. 


47 


a  depth  of  50  feet  in  marshy  soils,  and  even  in  quicksand  ;  the  sys- 
tem is  economical,  as  it  requires  no  outlay  for  excavation,  sheet- 
piling,  pumping,  etc. ;  the  work  goes  on  with  considerable  rapidity, 
because  a  pillar  strong  enough  to  support  90  tons  with  safety  can 
be  constructed,  under  favorable  conditions,  in  4  hours ;  the  dangers 
to  the  workmen  in  caisson  construction  are  eliminated ;  and  from 
the  amount  of  penetration  of  the  conical  weight  or  hammer,  the 
bearing  strength  of  the  strata  adjacent  to  the  pillars  may  be  approxi- 
mately determined.    An  elevation  and  a  cross-section,  illustrating 


Fig.  24.    The  Compressol  System  of  Concrete  Foundation, 


the  use  of  the  Compressol  system  of  foundation  construction  for 
a  building  erected  upon  soft  or  unstable  soil,  are  shown  in  Kig.  24, 
in  which  (a)  is  a  side  view  of  an  exterior  wall,  with  reinforced  con- 
crete lintels  bearing  upon  the  top  of  the  Compressol  foundations, 
supporting  their  load  of  brick-work  and  resting  upon  the  concrete 
wall  piers;  and  (b)  is  the  same  kind  of  construction  supporting  an 
interior  column. 

63.    COST  OF  CONCRETE  PILES.— The  cost  of  concrete 


48 


BUILDING  CONSTRUCTION.  (Ch.  II) 


piles  is  much  greater  than  that  of  timber  piles,  but  as  their  bearing 
strength  is  on  an  average  twice  as  great,  and  as  greater  dependence  . 
may  be  placed  upon  them,  the  number  of  piles,  and  consequently  the 
total  cost,  may  be' reduced. 

Prices  have  been  quoted  for  "Simplex"  concrete  piles  at  Salem,  - 
Mass.  The  number  of  piles  was  203  and  the  length  fixed  at  an 
average  of  17  feet  with  a  total  minimum  length  of  2,000  linear  feet. 
The  base  price  quoted  was  $1.46  per  foot,  additional  lengths  being 
charged  for  at  90  cents  per  foot.  For  lengths  shorter  than  17  feet, 
a  deduction  was  allowed  at  90  cents  per  foot. 

These  piles  were  16  inches  in  diameter  and  were  made  of  i  part 
of  Portland  cement,  2]^  parts  of  sand,  and  5  parts  of  broken  and 
crushed  stone.  The  prices  represent  a  fair  average  cost  of  concrete 
pile  construction  for  a  moderate  number  of  piles  cast  in  the  ground 
under  average  conditions. 

2.    SPREAD  FOUNDATIONS 

64.  SPREAD  FOUNDATIONS  IN  GENERAL.— Compress- 
ible soils  are  often  met  with  which  will  bear  from  i  to  2  tons  per 
square  foot  with  very  little  settlement,  and,  as  a  rule,  this  settlement 
is  uniform  under  the  same  unit-pressure.  When  unit-pressure  is 
referred  to  in  connection  with  foundation  soils,  the  pressure  per 
square  foot  of  bearing  surface  is  usually  understood.  In  such  cases 
it  is  often  cheaper  to  spread  the  foundations  so  as  to  reduce  the 
unit-pressure  to  the  capacity  of  the  soil  than  to  attempt  to  drive 
piles  or  to  use  sheet-piles  with  extensive  excavations  through  soft 
and  wet  soils.  ''Spread"  footings  may  be  built  of  reinforced  con- 
crete, consisting  of  concrete  with  iron  or  steel  tension-bars  imbedded 
therein,  of  steel  beams  and  concrete,  or  of  timber  and  concrete. 

A.    REINFORCED  CONCRETE  FOOTINGS 

65.  GENERAL  DESIGN.— One  of  the  most  efficient  and  eco- 
nomical^, micthods  of  constructing  spread  footings  is  that  of  rein- 
forced concrete,  consisting  of  beds  or  layers  of  concrete  to  which 
additional  resistance  to  transverse  stresses  is  added  by  embedding  in 
the  concrete,  steel  or  iron  rods  or  bars  placed  near  the  bottom  sur- 
faces of  the  footings,  where  the  tensile  stresses  are  developed.  This 
metal  reinforcement  consists  of  plain,  round,  square,  or  twisted 
bars,  or  of  expanded-metal,  woven  wire,  or  any  of  the  special 
patented  bars,  known  as  ''deformed  bars,"  now  on  the  market. 


SPREAD  FOUNDATIONS. 


49 


When  a  footing  is  constructed,  as  shown  in  Fig.  25,  at  (a),  so 
that  a  Hne  drawn  at  an  angle  of  60°  with  the  horizontal  will  inter- 
sect both  tli^  lower  outside  edges  of  the  footing  and  of  the  wall,  or 
of  the  solid  base  bearing  upon  the  footing,  there  is  little  danger 
of  the  failure  of  the  footing  from  bending  stresses,  whereas  there 
would  be  danger  of  such  failure  if  the  footing  had  a  considerable 


/ 

/  \- 

(a)  (h) 

Fig.    25.    Footings   with    Small   and   Large  Projections. 


projection,  as  shown  in  the  figure  at  (b).  In  the  latter  illustration 
the  projection  x  may  be  great  enough  to  result  in  causing  the  up- 
ward pressure  on  it  from  the  soil  to  bend  it  upward  and  to  cause  its 
failure  by  stresses  developed  by  flexure,  as  shown  by  the  fracture  at 
g.  This  principle  of  construction  is  further  treated  in  Chapter  III. 
66.    WALL  AND  COLUMN  FOOTINGS.— Reinforced  con- 


Fig.  26.     Concrete  Footing  with  Twisted  Reinforcement. 

Crete  spread  footings  may  be  used  for  walls  or  for  piers  or  columns. 

Fig.  26  shows  the  most  economical  section  for  a  concrete  and 
twisted  iron  footing.  In  building  the  footings  with  steel  beams,  the 
strength  of  the  concrete  is  practically  wasted,  while  in  this  method 
of  construction  it  is  all  utilized.  A  large  percentage  of  the 
tensile  strength  of  the  twisted  bars  can  be  utilized,  and,  being  held 


50 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


Typical    Reinforced    Concrete  Foot- 
ing for  Heavy  Wall. 


continuously  along  their  entire  length  by  the  concrete  as  a  screw 
bolt  is  held  by  the  nut,  they  neither  draw  nor  stretch,  except  as  the 
concrete  extends  with  them.  ^ 

Fig.  27  shows  a  typical  spread  footing  for  a  heavy  wall,  resting 
upon  soil  of  a  soft  and  unreliable  nature.    Here  the  bottom  of  the 

footing  is  reinforced  with 
the  steel  rods,  a,  to  prevent 
a  failure  of  the  projection 
of  this  footing  by  trans- 
verse or  bending  stresses. 
Above  the  spread  footing 
a  deep  course  of  concrete 
is  provided  with  reinforc- 
ing rods  or  bars,  h,  ex- 
tending longitudinally  or 
lengthwise  of  the  wall,  so 
so  that  if  the  soil  is  softer  in  some  places  than  in  others,  the 
heavy  upper  course  of  concrete  will  have  sufficient  strength  to 
span  the  weak  places  and  thus  prevent  unequal  settlements  and  un- 
sightly cracks  in  the  walls. 

A  typical  design  for  a  reinforced  concrete  column  footing  is 
shown  in  Fig.  28.  In  this  illustration  the  structural  steel  column  a 
is  provided  with  a  heavy  structural  steel  base,  designed  to  transmit 
the  load  sustained  by  the  column  to  the  top  bed  of  the  concrete  foot- 
ing. The  spread  footing  of  reinforced  concrete,  c,  has  another  block 
of  concrete,  b,  above  it,  to  lessen  the  projection  of  the  bottom  course. 
The  latter  is  reinforced  with  a  double  layer  of  rods  or  bars  crossing 
each  other  at  right  angles.  As  the  load  ordinarily  transmitted  by 
the  columns  to  the  reinforced  concrete  footing  is  considerable,  it  is 
considered  good  practice  to  provide,  under  the  bearing-plate  of  the 
column,  a  "mattress"  consisting  of  two  layers  of  reinforcing  rods, 
as  shown  at  d.  These  rods  reinforce  the  concrete  directly  beneath 
the  bottom  or  bearing-plate  of  the  column,  and  the  base  is  usually 
proportioned  with  an  area  which  stresses  the  concrete  up  to  500 
pounds  per  square  inch.  This  is  the  allowable  stress  for  reinforced 
concrete,  adopted  by  several  cities  in  the  compilation  of  their  build- 
ing laws. 

In  very  large  and  heavily  loaded  spread  column  footings  it  is 
sometimes  necessary  to  provide  vertical  reinforcement  throughout 
the  body  of  the  footing  by  introducing  stirrups  extending  up  into  the 


SPREAD  FOUNDATIONS. 


51 


body  of  concrete,  so  as  to  provide  sufficient  bond  between  the  several 
actual  or  theoretical  layers  of  the  concrete  to  prevent  them  from 


 :  ■  :  '    T  •  '•  M — 

Fig.  28.    Typical  Reinforced  Concrete  Footing  for  Column. 


f^rf^orced 
Comcrets  Column 


Basement  Tloor  Le^ef 


slipping  one  upon  the  other  when  they  are  subjected  to  transverse 
stress.  An  excellent  construction  for  such  a  column  footing  is 
shown  in  Fig.  29.  In  this  foot- 
ing the  reinforcement  consists  r-.l. 
of  two  layers  of  what  is  known 
as  the  "Kahn"  trussed  bar, 
shown  in  detail  in  Fig.  30.  In 
this  construction  the  prongs 
are  partially  sheared  from  the 
fin  of  the  bar  and  bent 
obliquely  upward,  forming  stir- 
rups, which,  besides  furnishing 
additional  bond  for  the  rein- 
forcing rods,  provide  against  any  possible  failure  from  the  hori- 
zontal shear  between  the  layers  of  the  concrete.  Other  deformed  bars 
may  be  used  for  spread  footing  reinforcement,  and  when  stirrups  or 


Kahn  Trus^Bar  F^ejnjorcemerrh 

29.    Reinforced    Concrete    Footing  for 
Heavily  Loaded  Column. 


52 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


members  to  resist  horizontal  shear  are  required,  they  may  be  made 
U-form,  from  ^-inch  round  bar,  or  from  by  i  inch  flat  bar, 
wired  or  otherwise  secured  to  the  main  reinforcing  bars  or  rods. 


67.  PLACING  THE  CONCRETE.— In  building  concrete  foot- 
ings, a  layer  of  concrete  from  3  to  6  inches  thick,  made  in  the  pro- 
portion of  I,  2  and  4,  should  first  be  laid,  and  the  iron  bars  laid  on 
and  tamped  down  into  it.  Another  layer  of  4  inches,  mixed  in 
the  same  proportions,  should  then  be  laid,  after  which  the  concrete 
may  be  mixed  in  the  proportions  of  i,  2^  and  5.  Each  layer  should 
be  laid  before  the  preceding  layer  has  had  time  to  harden ;  other- 
wise they  may  not  adhere  thoroughly. 

68.  STRENGTH  OF  REINFORCED  CONCRETE  FOOT- 
INGS.— In  order  that  reinforced  concrete  footings  may  be  safely 
constructed  it  is  necessary  to  determine  the  area  and  spacing  of  the 
reinforcing  bars  or  rods  at  the  bottom  of  the  footings,  and  also  to 
determine  whether  the  concrete  in  the  upper  part  of  the  footing  has 
sufficient  compressive  resistance. 

It  is  usual  in  designing  such  footings,  after  the  bearing  area  has 
been  determined  by  dividing  the  load  upon  them  by  the  safe  unit 
bearing  value  of  the  soil,  to  assume  or  decide  upon  their  thickness, 
•so  that  the  amount  of  steel  reinforcement  required  may  be  found. 

In  Fig.  31,  (a),  there  is  represented  diagrammatically  a  reinforced 
concrete  spread  column  footing.  The  distance  x  in  the  figure  rep- 
resents the  projection  of  the  footing  beyond  the  edge  of  the  column 
base,  where  the  footing  tends  to  fail  by  flexural  stresses,  because  the 
greatest  bending  moment  is  at  that  point.  The  upward  pressure  of 
the  soil  upon  this  projection  is  represented  by  the  forces  w,  w,  w, 
etc.,  and  their  sum  by  W  acting  at  their  center  of  gravity.  The  dis- 
tance of  this  resultant  force  W  from  the  edge  of  the  column  base 
is  the  lever  arm  with  which  this  force  tends  to  bend  the  footing 


Fig.   30.    Kahn  Trussed  Bar.  Detail. 


SPREAD  FOUNDATIONS. 


53 


around  the  edge  of  the  column,  and  is  equal  to  >^  x.  The 
depth  of  the  footing,  or  its  thickness,  is  represented  by  t^,  but  the 
theoretical  depth  for  the  purposes  of  calculation  is  the  distance  from 
the  middle  of  the  metal  reinforcement  to  the  top  of  the  concrete. 


f 





Concrete    .  T^fjng 

n     n     n     n I n^n  n 


■605000  R>und5 
Load  on  Column 


 L 


I  3kel  fTeenforcemenf    <  , 
Fig.    31.    Reinforced    Concrete    Column  Footing. 


In  order  to  determine  the  amount  of  steel  reinforcement  in  a 
spread  footing  of  reinforced  concrete,  the  following  formula  may  be 
used,  which  is  calculated  to  give  economical,  and  at  the  same  time, 
safe  results : 

IV  X  ^ 


27000  X  t 


(2) 


In  this  formula  W  is  equal  to  the  upward  pressure  of  the  soil,  in 
pounds,  on  a  strip  of  the  projection  of  the  footing  one-foot  in  width; 
X  is  the  projection  of  the  footing  beyond  the  edge  of  the  column 
base,  in  inches;  t  is  the  distance  from  the  top  of  the  concrete  footing 
to  the  middle  of  the  steel  reinforcement,  also  in  inches ;  while  the 
term  27,000  is  a  constant  deduced  from  the  usual  formula  for  rein- 
forced beams  of  rectangular  section,  and  is  based  upon  a  safe  unit 
tensile  stress  for  steel  of  about  16,000  pounds  per  square  inch.  The 
value  a,  to  be  determined  by  applying  this  formula,  is  the  area  in 
square  inches  required  for  the  steel  reinforcement  for  each  lineal 
foot  in  width  of  the  footing. 

Besides  finding  whether  there  is  sufficient  steel  reinforcement  in 
the  footing  by  determining  its  area  by  the  above  formula,  it  is  neces- 
sary to  ascertain  if  the  concrete  in  the  upper  part  of  the  footing  is 
over-stressed  by  the  compressive  forces  caused  by  the  bending.  The 
maximum  safe  compressive  stress  allowed  on  reinforced  concrete  in 


54 


BUILDING  CONSTRUCTION.  (Ch.  II) 


conservative  engineering  practice  is  500  pounds  per  square  inch 
ordinarily,  and  this  stress  should  not  be  exceeded.  To  determine 
the  maximum  compressive  stress  on  the  concrete  of  the  upper  part 

of  a  reinforced  concrete  spread  footing,  the  following  formula  may 
be  used: 

W  X  -r 

In  this  formula  W,  x  and  t  represent  the  same  values  as  given  for 
the  foregoing  formulas,  the  constant  being  4.59.  The  value  c  is  the 
compressive  stress  in  pounds  per  square  inch  near  the  upper  surface 
of  the  concrete  footing  at  the  edge  of  the  column  base. 

These  two  formulas  (2)  and  (3)  are  sufficiently  correct  for  all 
practical  purposes  and  are  based  on  the  latest  information  derived 
from  tests  on  reinforced  concrete  beams  of  rectangular  section. 
They  may  be  expressed  by  the  following  rules : 

Rule  I. — To  find  the  area  of  steel,  in  square  inches,  required  for 
each  lineal  foot  in  width  of  a  reinforced  concrete  footing:  divide 
the  product  of  the  upward  pressure  in  pounds  on  the  projection  of 
the  footing  one  foot  in  width  and  the  length  of  the  projection  of 
the  footing  in  inches,  by  27,000  multiplied  by  the  distance  in  inches 
from  the  middle  of  the  steel  reinforcement  to  the  top  surface  of  the 
concrete  footing. 

Rule  2. — To  find  the  amount  of  maximum  compressive  stress  per 
square  inch  upon  the  concrete  adjacent  to  the  top  surface  of  the 
concrete  footing:  divide  the  product  of  the  upward  pressure  in 
pounds  on  the  projection  of  the  footing  one  foot  in  width  and  the 
length  of  the  projection  in  inches,  by  4.59,  multiplied  by  the  square 
of  the  distance  from  middle  of  the  steel  reinforcement  to  the  top 
surface  of  the  concrete  footing. 

Example. — A  reinforced  column  footing  of  the  design  shown  in 
Fig.  31,  (&),  is  subjected  to  a  load  from  the  supported  column  of 
605,000  pounds,  and  it  is  desired  to  determine  what  amount  of  steel 
will  be  required  to  reinforce  this  footing,  and  also  whether  the  safe 
compressive  stress  in  the  concrete  at  the  point  a  is  exceeded. 

Solution. — The  area  of  the  footing  is  11  by  11  feet,  or  121  square 
feet ;  so  that  if  the  total  load  on  the  footing  is  605,000  pounds,  the 
load  per  square  foot  upon  the  soil  beneath  the  footing  is  605,000 
pounds  -f-  121,  or  5,000  pounds. 


SPREAD  FOUNDATIONS. 


55 


The  projection  of  the  footing  measured  by  the  distance  x  is  4  feet ; 
so  that  the  total  upward  pressure  on  a  portion  of  the  footing  one 
foot  in  width  is  5,000  pounds  x  4,  or  20,000  pounds. 

Since  or  the  distance  from  the  steel  reinforcement  to  the  top 
surface  of  the  concrete  footing,  is  24  inches,  all  of  the  terms  of  the 
second  member  of  formula  (2)  are  known,  and  the  sectional  area  of 
steel  required  for  each  foot  in  width  of  the  footing  is  found  as 
follows : 

20,000  X  48 

a  —   — —    =  1.40  sq.  ms. 

27,000  X  24  i 

The  section  area  of  a  J^-inch  square  twisted  bar  is  about  .76 
square  inches,  so  that  if  these  bars  are  spaced  6  inches  from  center  to 
center,  each  foot  in  width  of  the  footing  will  contain  two  bars  hav- 
ing a  total  area  of  1.52  square  inches. 

Having  found  the  amount  of  the  steel  reinforcement  for  the  foot- 
ing, it  is  necessary  to  determine  whether  tfte  concrete  of  the  footing 
is  over-stressed  by  compression.  Formula  (3)  is  used  to  find  the 
value  of  c,  which  must  not  exceed  500  pounds  per  square  inch. 
Substituting  in  the  formula, 

20,000  X  48         ^  ,  . 

c  —  —  =  36^  pounds  per  sq.  m. 

4.59  X  24  X  24    ^     ^  ^ 

From  the  result  of  the  above  calculation  it  is  observed  that  the 
value  c  of  363  pounds  per  square  inch  is  well  within  the  limit  of  500 
pounds  per  square  inch,  so  that  the  footing  as  designed  may  be  con- 
sidered as  amply  safe ;  or  the  thickness  may  be  decreased,  though 
the  saving  in  concrete  will  in  all  probability  be  less  than  the  additional 
cost  of  the  steel  required  for  the  reinforcement  due  to  the  decreased 
distance 


*  These  formulas,  (2)  and  (3),  are  based  upon  tests  made  on  reinforced  concrete 
beams,  and  upon  formulas  derived  from  these  tests,  by  Professor  A.  N.  Talbot,  of  the 
University  of  Illinois.  In  this  derivation,  consider  that  the  moment-arm  for  the  couple 
formed  by  the  tension  in  the  steel  and  the  compression  in  the  concrete  is  0.87.  This 
is  an  average  value  for  reinforcement  under  i  per  cent.  Equating  the  bending  moment  to 
the  resisting  moment  gives: 

M  =   1/2  W  X  =  0.87  a  f  t 

Comparing  this  with  formula  (2),  /  is  seen  to  be  about  15,5000  pounds  per  square  inch. 

In  dealing  vi^ith  the  compression,  consider  that  the  neutral  axis  is  0.42  t  below  the 
top  surface,  and  use  the  straitrht  line  relation.  Equating  the  bending  moment  and  the 
resisting  moment  and  solving  for  c  gives: 

W  X 


4-5  t 


Professor  Talbot  states  that  "it  must  be  borne  in  mind  that  footings  will  be  very  short 
beams,  and  that  for  short,  beams  diagonal  tension  failures,  or  so-called  shearing  failures 
are  likely  to  result.    The  vertical  shearing  stress  will  then  be  the  controlling  feature  of 


56 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


69.  TABLE  OF  STRENGTH  AND  PROPORTIONS  OF 
FOOTINGS.— The  author  has  prepared  Table  IV,  giving  the 
strength  and  proportions  of  reinforced  concrete  footings,  which  he 
beheves  have  a  large  margin  of  safety.  While  the  values  given  in 
this  table  vary  slightly  from  the  results  obtained  from  the  preceding 
formulas,  the  variations  are  on  the  side  of  safety,  the  values 
giving  an  excess  of  steel  v^ithout  overstressing  the  concrete  to  a  great 
extent.  In  the  table  two  sizes  of  bars  are  given,  with  the  correspond- 
ing safe  loads  for  the  footings,  the  other  measurements  applying  to 
both  cases.  The  measurements  in  the  third  column  refer  to  the 
width  of  the  brick  or  stone  footing  resting  on  the  concrete.  The 
greater  the  width  of  this  footing  in  proportion  to  the  width  of  the 
concrete,  the  less  will  be  the  stress  in  the  tension  rods. 

TABLE  IV. 

Proportions    and    Strength    of    Concrete    Footings  with 
TwifTED  Iron  Tension  Bars. 


WIDTH  OF  1 

FOOTING 
IN  FEET. 

THICKNESS 

OF  CON- 
CRETE. 

WIDTH  OF 

STONE 

FOOTING. 

DISTANCE 
BETWEEN 
CENTRES 
OF  BARS. 

SIZE  OF 
SQUARE 
BAR. 

SAFE  LOAD 
PER  LINEAL 
FOOT. 

SIZE  OF 
SQUARE 
BAR. 

SAFE  LOAD 
PER  LINEAL 
FOOT. 

1 

Ft. 

In. 

Ft. 

In. 

Inches. 

Inches. 

Tons. 

Inches. 

Tons. 

20 

3 

6 

6 

0 

8 

2 

78 

I| 

66 

18 

3 

3 

5 

6 

8 

2 

76 

If 

56 

16 

2 

10 

5 

0 

7 

If 

73 

li 

50 

14 

2 

8 

4 

8 

7 

70 

If 

49 

12 

2 

6 

4 

4 

6 

If 

65 

li 

48 

10 

2 

3 

4 

0 

6 

li 

65 

I 

42 

8 

2 

0 

4 

0 

6 

I 

60 

3 

T 

40 

6 

I 

8 

3 

6 

6 

f 

55 

1 

29 

70.  SQUARE  TWISTED  BARS  FOR  REINFORCEMENT. 
• — For  some  years  the  use  of  square  twisted  bars  for  reinforcing  con- 

tiie  strength  of  the  footing  unless  some  form  of  web  reinforcement  is  used  to  overcome  this 
defect.  The_  ordinary  designer  will  be  likely  to  overlook  this  feature.  The  working  stress 
for  the  vertical  shear  for  short  beatns  without  efficient  web  reinforcement  should  not  run 
more  than  from  30  to  50  pounds  per  square  inch.  Beams  with  poor  concrete  fail  with 
values  as  low  as  60  pounds  per  square  inch,  and  the  best  ordinary  concrete  does  not  run 
more  than  125  pounds  per  square  inch. 

"Bond  stresses  may  control  the  footing,  and  not  more  than  from  50  to  75  pounds  to 
the  square  inch  of  surface  should  be  allowed  for  plain  bars.  In  the  case  of  bars  bent  up, 
the  bond  stress  may  become  the  controlling  element.  It.  should  be  noted  also  that  where 
'bending-up'  is  practiced,  the  bend  should  begin  at  the  offset.  It  may  also  be  suggested 
that  stepped  or  sloped  effects  will  be  of  advantage  in  overcoming  the  difficulties  involved 
in  high  shearing  stresses." 

In  regard  to  the  form  of  formulas  (2) and  (3),  and  to  their  "mathematical  dimen- 
sions," the  latter  will  be  found  to  be  correct,  when  the  formulas  from  which  they  are 
derived  are  borne  in  mind;  and  the  correct  resulting  dimensions  will  be  given  to  the 
27,000  and  to  the  4.59  appearaing  in  the  denominators  of  the  second  members  of  the 
equations. 


SPREAD  FOUNDATIONS. 


57 


Crete  was  protected  by  the  patents  of  Ernest  L.  Ransome,  of  San 
Francisco,  Cal.,  and  subsequently  by  the  rights  owned  by  the  Ran- 
some &  Smith  Co.,  of  New  York,  Chicago  and  San  Francisco. 

All  patents  relating  to  the  use  of  square  twisted  bars  for  reinforced 
concrete  construction  have  now  expired,  and  many  firms  are  manu- 
facturing this  type  of  reinforcing  bar  by  both  cold  and  hot  twisting. 
They  are  now  very  generally  used  in  reinforced  concrete  con- 
struction. 


f^)  (b  (c) 

Fig.  32.    different  Arrangements  of  Rods  in  Reinforced  Concrete  Footings. 


71.  PLACING  THE  RODS  IN  SPREAD  FOOTINGS.-^ 
There  are  several  ways  of  arranging  rods  in  reinforced  concrete 
column  footings,  some  of  which  are  shown  in  Fig.  32  at  (a),  (b), 
and  (c).  The  method  shown  in  the  figure  at  (a)  is  the  one  com- 
monly used  and  consists  of  two  layers  of  reinforcing  rods  placed  at 
right  angles  to  each  other  and  spaced  an  equal  distance  apart  from 
center  to  center.  Where  great  economy  is  required  every  alternate 
rod  may  be  shortened  somewhat,  because  the  bending  moment  in  the 
footing  becomes  smaller  toward  the  outer  edge,  where  it  is  zero,  and 
consequently  less  reinforcement  is  required  there. 

The  best  practice  in  the  design  of  reinforced  concrete  column  foot- 
ings consists  in  placing  several  layers  of  rods,  some  at  right  angles 
with  each  other  and  some  diagonally,  as  shown  in  the  figure  at  (b). 

Sometimes  an  effort  is  made  to  save  concrete  by  making  the  foot- 
ing octagonal  in  plan,  as  shown  at  (c),  as  the  corners  of  a  square 
footing  are  considered  relatively  weak,  and  hence  properly  omitted. 
Where,  however,  they  are  reinforced  as  in  the  figure  at  (b),  they  are 
?bout  as  effective  as  any  portion  of  the  area  of  the  footing,  as  far 
as  the  distribution  of  the  pressure  on  the  soil  is  concerned. 


58,  BUILDING  CONSTRUCTION.  (Ch.  II) 

B.    STEEL  BEAM  FOOTINGS 

72.  GENERAL  DESIGN. — When  it  is  necessary  to  spread  the 
foundations  over  12  or  15  feet  in  each  direction,  with  a  very  small 
height  to  the  footings,  as  is  the  case  in  Chicago,  steel  beams  are  used 
to  furnish  the  necessary  transverse  strength.  For  tall  buildings, 
even  when  constructed  on  solid  ground,  it  is  sometimes  found  desir- 
able to  use  steel-beam  grillage  footings  to  distribute  the  load.  Such 
footings  are  usually  cheaper  than  massive  masonry  footings,  though 
they  cannot,  as  a  rule,  compete  in  cost  with  footings  of  reinforced 
concrete. 

The  manner  of  using  the  beams  is  shown  in  Figure  35. 

In  preparing  the  footings,  the  ground  is  first  carefully  levelled  and 
the  bottom  of  the  pier  located.  If  the  ground  is  not  compact  enough 
to  permit  of  excavating  for  the  concrete  bed  without  the  sides  of  the 
pit  or  trench  falling  in,  heavy  planks  or  timbers  should  be  set  up  and 
fastened  together  at  the  corners  and,  if  necessary,  tied  between  with 
rods,  to- hold  the  concrete  in  place  and  to  prevent  its  spreading  before 
it  has  thoroughly  set.  A  layer  of  Portland  cement  concrete,  made  in 
(he  proportion  of  i,  2  and  4,  and  from  6  to  12  inches  thick,  accord- 
ing to  the  weight  on  the  footings,  should  then  be  filled  in  between  the 
timbers  and  well  rammed  and  levelled  off.  If  the  concrete  is  to  be  12 
inches  thick  it  should  be  deposited  in  two  layers.  Upon  this  concrete 
the  beams  should  be  carefully  bedded  in  i  to  2  Portland  cement 
mortar,  so  as  to  bring  them  nearly  level  and  in  line  with  each  other. 

The  distance  apart  of  the  beams,  from  center  to  center,  may  vary 
from  9  to  20  inches,  according  to  the  height  of  the  beams,  thickness 
of  concrete  and  estimated  pressure  per  square  foot.  They  must  not 
be  so  far  apart  that  they  will  crush  through  the  concrete  (see  Article 
76.),  and  on  the  other  hand  there  must  be  a  space  of  at  least  2  inches 
between  edges  of  the  flanges  to  permit  the  introduction  of  the  con- 
crete filling.  As  soon  as  the  beams  are  in  place  the  spaces  between 
them  should  be  filled  with  i,  2  and  4  concrete,  the  stone  being  broken 
into  pieces  that  will  pass  through  a  i^-inch  ring,  and  the  concrete 
being  well  rammed  into  place,  so  that  no  cavities  will  be  left  in  the 
center.  The  concrete  must  also  be  carried  at  least  3  inches  beyond 
the  beams  on  the  sides  and  ends,  and  kept  in  place  by  planks  or 
timbers. 

73.  CONCRETE  BETWEEN  LAYERS;  BASE-PLATE, 
ETC. — If  two  or  more  layers  of  beams  are  used,  the  top  of  each  layer 


SPREAD  FOUNDATIONS. 


59 


should  be  carefully  levelled,  after  the  concrete  has  been  put  in  place, 
with  I  to  2  Portland  cement  mortar,  not  more  than  ^  an  inch  thick 
over  the  highest  beams,  and  in  this  the  next  layer  of  beams  should 
be  bedded,  and  so  on. 

The  stone  or  metal  base-plate  or  footing  should  also  be  bedded  in 
Portland  cement  mortar,  not  more  than  ^  of  an  inch  thick  above 
the  upper  tier  of  beams. 

After  the  base-plate  or  stone  footing  is  in  place,  at  least  3  inches  of 
concrete  should  be  laid  above  the  beams  and  at  the  sides  and  ends ; 
and  when  this  is  set  the  whole  outside  of  the  footings  should  be  plas- 
tered with  I  to  2  Portland  cement  mortar. 

74.  QUESTION  OF  PAINTING  STEEL  BEAMS  IN  CON- 
CRETE.— It  was  formerly  the  practice  to  thoroughly  clean  the 
beams  with  wire  brushes  before  they  were  laid,  and,  while  absolutely 
dry,  to  either  paint  them  with  iron  paint  or  else  to  heat  and  coat 
them  with  two  coats  of  asphalt. 

The  protection  of  steel  when  imbedded  in  concrete  work  seems 
to  be  so  complete  that  many  engineers  are  not  insisting  upon  the 
painting  of  the  grillage  beams,  as  the  cem.ent  in  contact  with  the 
steel  prevents  any  serious  corrosion.  In  fact,  probably  greater 
strength  and  continuity  of  action  is  secured  between  the  concrete 
and  the  steel  of  the  footing  when  the  latter  is  left  unpainted,  though 
such  a  combined  action  is  not  considered  in  calculating  the  strength 
of  grillage  construction, 

75.  NUMBER  OF  LAYERS  OF  BEAMS.— When  iron  and 
concrete  foundations  were  first  used  in  Chicago,  railroad  rails, 
on  account  of  their  lower  cost,  were  employed  to  give  the  required 
transverse  strength. 

The  footings  were  built  up  with  five  or  six  layers  of  rails,  placed 
at  right  angles  to  each  other,  each  layer  diminishing  in  number 
until  the  upper  surface  was  stepped  off  sufficiently,  but  not  enough 
to  exceed  unduly  the  proper  size  of  the  column  base  As  each  layer 
of  rails  was  laid,  concrete  was  filled  between  and  around  them,  and 
when  completed  the  footing  resembled  a  simple  concrete  pier. 

The  footings  under  the  Rand  and  McNally  building,  Chicago,  erected  in 
l8gi,  were  of  this  character,  five  layers  of  rails  being  used  in  most  of  the  foot- 
ings.   In  some  of  the  footings  the  upper  layer  consisted  of  12-inch  beams. 

Building  up  footings  in  successive  tiers,  however,  is  not  as  eco- 
nomical in  the  use  of  the  steel  as  the  method  of  building  them  up 
with  two  layers  of  deep  beams. 


6o 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


7 


Ll 


It  should  also  be  borne  in  mind  that  the  beams  spread  the  load 
over  the  ground  only  by  their  transverse  strength,  and  they  should, 

therefofe,  be  used  in  the  same  way  that 
they  would  be  were  the  foundation  re- 
versed, the  wall  or  column  becoming 
the  support  and  the  ground  the  load, 
as  shown  in  Fig.  33. 

76.    NUMBER   OF    BEAMS  IN 
THE  UPPER  COURSE.— When  sev- 
eral   beams    are   used    in   the  upper 
I  course  or  layer,  there  is  a  tendency  to 

Fig.  33.     Illustration  of  Flexure  in    COUCCUtrate    the    Wcigllt    OU    the  OUtcr 
Steel  Beam  Grillage.  . 

beams  of  the  upper  layer  owmg  to  the 
deflection  of  the  beams  below.  The  author  therefore  advocates  the 
use  of  as  few  beams  as  practicable  in  the  upper  course  and  where 
the  conditions  will  permit,  either  a  single  built-up  girder  or  two 
heavy  beams,  and  in  the  lower  course  the  deepest  beams  consistent 
with  economy.  If  the  beams  in  the  lower  course  permit  of  a  spacing 
much  greater  than  their  height,  a  layer  of  rails  should  be  imbedded 
in  the  top  of  the  concrete  to  prevent  the  beams  from  breaking 
through.  The  rails,  however,  would  in  no  w^ay  affect  the  stress  or 
bending  action  in  the  beams. 

For  a  further  discussion  of  the  use  of  steel  beams  in  foundations,  the 
reader  is  referred  to  an  article  by  the  author  in  Architecture  and  Building  of 
August  24,  1895. 

Examples  of  steel-beam  and  concrete  footings  are  also  given,  with  illus- 
trations, in  the  Engineering  Record  of  December  12,  1891,  and  June  i,  1895, 
and  the  later  issues  of  the  various  journals  on  architecture  and  engineering 
contain  numerous  articles  and  illustrations  of  this  method  of  construction. 

77.  EXAMPLE  OF  STEEL  BEAM  GRILLAGE  ON  SOLID 
ROCK. — The  use  of  steel  beam  grillage  foundations  for  tall  build- 
ings has  become  so  universal  that  numerous  accounts  and  illustra- 
tions of  this  type  of  construction  may  be  found  in  the  current  num- 
bers of  the  architectural  and  engineering  publications. 

While  the  use  of  grillage  foundations  is  usually  confined  to  com- 
pressible soils,  it  is  sonietimes  employed  to  distribute  the  load  of  the 
columns  over  a  solid  rock  foundation.  A  notable  example  of  the 
use  of  grillages  of  steel  beams  being  used  for  this  purpose  is  found 
in  the  building  for  the  Metropolitan  Life  Insurance  Co.,  New  York. 
In  this  structure  the  tower,  which  is  the  highest  of  all  building 


SPREAD  FOUXDATIONS. 


6i 


towers,  IS  supported  upon  steel-beam  grillage  construction  as 
illustrated  in  Fig.  34.  From  this  figure  it  will  be  observed  that  the 
main  columns  are  supported  upon  four  tiers  of  steel  beams  while 
the  secondary  columns  rest  upon  two  tiers  of  beams.  The  grillage 
and  column  base  is  in  each  case  entirely  embedded  in  concrete. 


l^'g-  34-    Grillage  Foundations  on  Rock.    Metrojiolitan  Life  Insurance  Company's  Build- 
ings,  New  York. 


78.  METHOD  OF  DETERMINING  THE  SIZE  OF  THE 
STEEL  BEAMS. — As  the  purpose  of  the  beams  is  to  distribute  the 
load  coming  from  the  foundation  wall  or  base-plate  evenly  over  the 
ground,  so  that  the  pressure  on  each  square  foot  of  the  soil  will  be 
the  same,  it  is  obvious  that  the  beams  must  have  sufiflcient  trans- 
verse strength  to  keep  them  from -bending,  so  that  they  will  settle  as 
much  at  the  outer  ends  as  in  the  middle.  The  effect  on  the  beams 
shown  in  Fig.  35,  when  resting  on  a  compressible  soil  and  heavily 
loaded  from  above,  is  to  cause  the  ends  of  the  beams  to  bend  up- 
ward, thus  stressing  the  beams  the  most  in  the  middle ;  the  stress  in 
the  beams  being  the  same  as  if  they  were  supported  on  a  pier  in  the 
middle  and  loaded  with  a  distributed  load,  as  shown  in  Fig.  33. 

79.  DETAILS  OF  PROCEDURE  AND  EXAMPLE.  GRIL- 
LAGE UNDER  WALL. — The  best  method  of  determining  the  size 
of  the  beams  is  by  computing  the  maximum  bending  moments  for 
the  steel  beams  and  obtaining  the  required  "section  modulus"  or 
"section  factor/'  by  dividing  by  the  safe  unit  fiber  stress  of  the  steel. 
When  the  section  modulus  has  been  obtained,  the  corresponding 


62  BUILDING  CONSTRUCTION.  (Ch.  II) 


value  may  be  found  in  the  tables  of  the  steel  manufacturers'  hand- 
books, from  similar  tables  given  herewith  or  in  Kidder's  ''Architects' 
and  Builders'  Pocket-Book,"  and  the  beam  of  the  required  size  and 
weight  selected. 


Cro3:)  -  Section  Side  -  View 

Fig.    35.    Example    of    Steel    Beam  Grillage. 

The  maximum  bending  moment  for  a  grillage  beam  may  be 
obtained  by  the  following  formula : 

M=yi,W  {L—B)  (4) 

in  which  M  is  the  maximum  bending  movement  in  inch-pounds ;  W 
the  load  in  pounds  on  one  beam  of  the  grillage ;  L  the  length  of  the 
grillage  beam  in  inches,  and  B  the  width  of  the  upper  tier  or  base  in 
inches.    See  Fig.  35. 

When  the  maximum  bending  moment  M  is  divided  by  the  safe 
unit  fiber  stress  of  the  steel,  usually  taken  at  16,000  pounds  per 
square  inch,  the  section  modulus  or  Q  is  obtained.  Or,  this  value 
may  be  found  directly  by  the  formula, 

Q=^^  (5) 
1 28,000 

The  section  modulus  and  several  other  properties  of  rolled  steel 
I-beams  of  standard  section  are  given  in  Table  V. 


SPREAD  FOUNDATIONS.  63 
TABLE  V. 

Section  Modulus  for  Rolled  Steel  I-Beams  of  Different 
Sizes  and  Weights. 


Depth  of  Beam 

Weight  Per  Foot 

Area 

Thickness  of  Web 

Width  of  Flange 

Section  Modulus 
Axis  Square  to  Web 

Depth  of  Beam 

Weight  Per  Foot 

Area 

Thickness  of  Web 

Width  of  Flange 

Section  Modulus 
Asi^  Square  to  Web 

Ins. 

Lbs. 

Sq.  In. 

Ins. 

Ins. 

Q 

Ins. 

Lbs. 

Sq.  In. 

Ins. 

Ins. 

Q 

20 
20 
20 
20 
20 
20. 

90 
85 
80 
75 
70 
65 

26.4 
25.0 

<iO.O 

22.1 
20.6 
19.1 

.78 
.76 
.by 
.66 
.57 
.50 

6.75 
6.45 
6.38 
6.16 
6.07 
6.00 

150.6 
139.4 
134.5 
124.7 
119.8 
114.9 

10 
10 
in 

10 
10 

40 
35 
66 
30 
27 
25 

11.8 
10.3 
Q  n 
y.l 

8.8 
7.9 
7.3 

.58 
.43 
.6i 
.45 
.37 
.31 

5.21 
5.06 
5.00 
4.89 
4.81 
4.75 

35.7 

33.2 
32.$ 
26.J^ 
25.5 
24.5 

18 
18 
18 
18 
18 
18 

80 
75 
70 
65 
60 
55 

23.5 
22.1 
20.6 
19.1 
17.6 
16.2 

.70 
.62 
.65 
.64 
.55 
.47 

6.63 
6.55 
6.37 
6.17 
6.08 
6,00 

125.7 
121.3 
108.1 
98.5 
94.1 
89.6 

9 
9 

9 
9 
9 
9 

33 
31 ) 

27 

25 

21 

9.7 
8  8 
7^9 
7.3 
6.9 
6.2 

.51 
41 
!31 
.40 
.35 
.27 

4.95 
•  ^  g5 

4!75 
4.63 
4.58 
4.50 

27.^ 

24.& 
20.5 
19.ft 
18.T 

15 
15 
15 
15 
15 
15 
15 
15 
15 

80 
75 
70 
65 
CO 
55 
50 

23.5 
22.1 
20.6 
19.1 
17.6 
16.2 
14.7 
13.2 
12.4 

.91 
.81 
.72 
.62 
.52 
.55 
.45 
.46 
.40 

6.39 
6.29 
6.20 
6.10 
6.00 
5.85 
5.75 

99.7 

9G.0 
92.4 
88.7 
85.0 
74.3 
70.6 

8 
8 
8 
8 
8 
7 

27 
25 
22 
20 
18 
22 

7.9 
7.3 
6.4 
5.9 
5.2 
6.4 

.48 
.40 
.29 
.32 
.25 
.36 

4.56 
4.49 
4.38 
4.20 
4.13 
4.17 

19.4 
18.S 
17.4 
15.0 
14.2 

14. a 

45 
42 

5.58 
5.50 

59.5 
57.3 

7 
7 

20 
17^ 
15 
20 

n% 

15 
12 
1) 
13 

5.7 
5.1 

.28 
.34 

4.09 
3.98 

13.S 
11.5 

12 
12 
12 
12 
12 
12 
12 
12 

65 
60 
55 
60 
45 
40 
35 

19.1 
17.6 
16.1 
14.7 
13.2 
11.8 
10.3 

.88 
.75 
.63 
.64 
.51 
.39 
.44 

6.25 
6.12 
6.00 
5.75 
5.62 
5.50 
5.22 

65.6 
62.6 
59.7 
52.8 
49.8 
46.9 
38.8 

7 
6 
6 
6 
6 
5 
5 

4.4 
5.7 
5.0 
4.4 
3.6 
4.4 
3.8 

.23 
.50 
.37 
.25 
.22 
.38 
.26 

3.88  ' 

3.77 

3.64 

3.52 
3.38 
3.25 
3.13 

lO.S 

lo.a 

9.5T 
8.81 
7.25 
6.77 
6.2s 

9.3 

.35 

5.13 

36.7 

5 

12 

3.6 

.34 

3.13 

5.3{> 

NoTE—The  above  table  Is  compiled  from 
the  Passaic  Rolling  Mill  Go's,  hand-hook 
and  agrees  closely  with  the  Standard 
Sections    adopted    by    the  American 
Steel  Manufacturers  Association. 

5 
4 

4  ' 
4 

10 

^« 

2.9 
2.9 
2.2 
1.8 

.21 
.39 
.20 
.18 

3.00 

2^50 
2.19 

4.87 
3.42: 
2  95 
2.30 

Owing  to  the  tendency  of  the  beams  in  bending,  to  concentrate  the 
load  on  the  outer  edges  of  the  masonry  footing,  and  thus  crush  them, 
which  action  would  have  the  same  effect  on  the  beam  as  lengthening 
the  arm  or  projection  (see  article  in  Architecture'  and  Building  pre- 
viously referred  to),  the  author  recommends  that  when  the  course 


64  BUILDING  CONSTRUCTION.  (Ch.  II) 

above  the  beams  is  of  stone,  brick  or  concrete,  at  least  one-third  the 
width  of  the  masonry  footing  he  added  to  the  actual  projection. 

The  apphcation  of  the  formulas  (4)  and  (5)  will  be  more  clearly 
shown  by  the  following  example,  the  conditions  of  which  are  illus- 
trated in  Fig.  35.  Owing  to  the  size  and  to  the  nature  of  the 
material  of  the  bottom  course  of  the  wall,  the  tendency  to  crush  at 
the  outer  edge  of  this  course  is  neglected : 

Example  1. — A  building  is  to  be  erected  on  a  soil  of  which  the 
safe  bearing  power  is  but  2  tons  per  square  foot,  and  the  pressure  on 
each  lineal  foot  of  wall  is  20  tons.  It  is  decided  to  build  the  footings 
as  shown  in  Fig.  35.  What  should  be  the  dimensions  and  weight 
oi  the  beams? 

Solution. — As  the  total  pressure  under  each  lineal  foot  of  wall  is 
20  tons,  and  the  safe  bearing  power  of  the  soil  2  tons  per  square  foot, 
the  footings  must  be  20  -f-  2,  or  10  feet  wide.  As  4^feet  granite 
blocks  are  used  for  the  bottom  course  of  the  wall,  the  value  of  L — B 
in  formula  (5)  will  be  72  inches;  so  that  if  the  beams  are  spaced  12 
inches  on  centers,  the  load  W  will  be  20  tons,  or  40,000  pounds,  and 

40,000  X  72  • 

Q  —  5  ~,  or  22.5. 

128,000 

From  Table  (V),  giving  the  Section  Modulus  for  Rolled  Steel 
I-Beams  of  Different  Sizes  and  Weights,  it  is  found  that  a  lo-inch 
25-pound  beam  is  the  most  economical  section  to  use  for  the  grillage 
footijig.  The  beam  selected  from  the  table  has  an. excess  of  strength 
as  its  section  modulus  is  24.5.  This,  however,  is  as  close  a  selection 
as  can  usually  be  made.  When  there  are  no  values  in  the  table  cor- 
responding closely  with  the  section  modulus  required,  a  dififerent 
spacing  should  be  tried  in  order  to  obtain  more  economical  results. 

80.  TABLE  FOR  FINDING  SAFE  LOAD  ON  GRILLAGE 
BEAMS. — The  use  of  the  above  formulas  and  calculations  may  be 
avoided  by  referring  to  the  following  table  giving  the  total  safe 
load  in  tons  of  2,000  pounds  on  a  single  beam,  for  the  various  sizes 
of  steel  I-beams,  and  for  different  values  of  L — B.  The  values  in 
the  table  represent  the  safe  load  in  tons  which  one  beam  of  the 
grillage  will  support  throughout  its  length. 

By  the  use  of  this  table,  which  is  compiled  from  the  Passaic 
Rolling  Mill  Co.'s  hand-book,  no  calculations  are  necessary  except 


SPREAD  FOUNDATIONS. 
TABLE  VL 


65 


Safe  Load  in  Tons  of  2,000  Pounds  on  One  Beam  of  Grillage 

Footings. 


Beam 


Projection  both  sides  of  Grillage  Beam,  or  L—B,  in  feet 


Depth 


Weight 

in 
Pounds 
Per  Foot 

80 
75 
70 
65 


75 
65 
60 
55 

65 
60 
55 
45 
42 

60 
55 
45 
40 
35 

40 
80 
27 
25 

30 
27 
25 
21 

25 
20 
18 

20 
15 

171^ 
12 


94. 


63.6 
53.2 
50.0 
41.4 
39.2 

38.0 
28.8 
27.2 
26.2 

27.6 
26.2 
21.8 
20.0 

19.8 
16.0 
15.1 

14.5 
11.3 

10.2 
7.8 


119 
111 


108 
87.5 
83.6 


78.8 
75.6 
66.0 
52.8 
50.8 

55.6 
53.0 
44.2 
41.6 
34.6 
32.8 

31.8 
24.0 
22.6 
21.8 

23.0 
21.8 
18.2 
16.7 

1G.5 
13.3 
12.6 

12.1 
9.4 

8.5 
6.5 


102 
95 

91.2 
87.5 


92.4 
75.0 
71.6 
68.4 

67.6 
64.8 
56.6 
45.4 
43.6 

47.8 
45.6 
38.0 
35.8 
29.6 
28.0 

27.2 
20.6 
19.4 
18.7 

19.7 
18.7 
15.6 
14.3 

14.2 
11.4 
10.8 

10.4 
8.1 

7.3 
5.5 


83.2 
79.8 
76.6 


80.8 
65.6 
62.8 
59.8 

59.2 
56.6 
49.6 


41.8 

39  8 
33.2 
31.3 
25.9 
24.5 

23.8 
18.0 
17.0 
16.3 

17.3 
16.4 
13.7 
12.5 

12.4 
10.0 
9.5 

9.1 
7.1 

6  4 
4.8 


79.8 
73.8 
71.0 
68.2 


71.8 
58.4 
55.8 
53.2 

52.6 
50.4 
44.0 
35.2 
34.0 

37.1 
35.4 
29.5 
27.8 
23.0 
21.8 

21.2 
16.0 
15.1 
14.5 

15.4 
14.6 
12.2 
11.1 

11.0 
8.9 
8.4 

8.1 
6.3 

5.7 
4.3 


71.7 
66.5 
63.9 
61.3 


64.7 
52.5 
50.2 
47.8 

47.3 
45.4 
39.6 
31.7 
30.6 

33.4 
31.8 
26.6 
25.0 
20.7 
19.6 

19.0 
14.4 
13.6 
13.1 

13.8 
13.1 
10.9* 
10.0 


8.0 
7-6 


7.3 
5.7 


5.1 
3.9 


&5.2 
60.5 
58.1 
55.7 


58.8 
47.7 
45.6 
43.5 

43.0 
41.2 
36.0 
28.8 
27.8 

30.4 
28.8 
24.2 
22.7 
18  8 
17.9 

17.3 
13.1 
12.4 
11.9 

12.6 
11.9 
9.9 
9.1 

9.0 
7.3 
6.9 

6.6 
5.1 


12 


59.8 
55.4 
53.2 
51.0 


53.9 
43.8 
41.8 
39.8 

39.4 
37.8 
33.0 
26.4 
25.4 


26.5 
22.1 
20.8 
17.3 
16.4 

15.9 
12.0 
11.3 
10.9 

11.5 
10.9 
9.1 
8.3 

8.3 
6.7 
6.3 

6.1 
4.7 


13 


55.2 
51.2 
49.1 
47.1 


49.8 
40.4 
38.6 
3i).8 

36.4 
34.9 
30.5 
24.4 
23.5 

25.7 
24.5 
20.4 
19.2 
15.9 
15.1 

14.7 
11.1 
10.5 
10.1 

10.2 
10.1 
8.4 
7.7 

7.6 
6.1 

5.8 


14 


51.2 
47.5 
45.6 
43.8 


37.5 
35.8 
34.2 

33.8 
32.4 
28.3 
22.7 
21.8 

23.9 
22.8 
19.0 
17.9 
14.8 
14.0 


15 


47.8 
44.3 
42.6 
40.9 


43.1 
35.0 
33.4 
31.9 

31.5 
30.3 
26.4 
21.1 
20.4 

22.3 
21.2 
17.7 
16.7 
13.8 
13.1 


to  determine  the  difference  between  the  width  of  the  superimposed 
footing  or  tier  of  beams,  and  the  grillage  beams.  The  results 
obtained  by  this  table  should  agree  with  the  results  obtained  from 
formulas  (4)  and  (5). 

Thus,  in  the  above  example,  to  use  the  table,  it  is  simply  neces- 
sary to  look  down  the  column  headed  6  until  the  value  nearest  to 
20  tons  is  found.  This  will  indicate  the  lightest  weight  beam  that 
can  be  used  and  this  beam  is  found  to  be  a  lo-inch  25-pound  beam 
having  a  strength  value  of  21.8  tons.    A  9-inch  27-pound  beam 


66 


BUILDING  CONSTRUCTION.  (Ch.  II) 


would  also  do,  but  as  it  weighs  more  than  the  previously  selected 
beam  there  would  be  no  economy  in  using  the  shallower  beam 

When  there  is  no  value  corresponding  with  the  required  one  it  is 
necessary  to  use  formulas. 

8i.  EXAMPLE.  GRILLAGE  UNDER  PIER.— In  the  case 
illustrated  in  Fig.  36  the  size  of  both  the  upper  and  lower  beams 
are  determined  in  the  same  way  as  in  Example  L,  the  value  of 

Example  II. — The  basement 
columns  of  a  ten-story  build- 
ing, resting  on  footings  as 
shown  in  Fig.  36,  are  re- 
quired to  sustain  a  permanent 
load  of  400,000  pounds.  What 
should  be  the  size  of  the 
beams  in  the  footings,  the 
supporting  power  of  the  soil 
being  but  2  tons? 

Solution. — By  dividing  the 
load  by  the  bearing  power  of 
the  soil  the  area  of  the  foot- 
ing is  found  to  be  equal  to 
100  square  feet,  so  that  the 
dimensions  of  the  footing  are 
10  by  10  feet.  The  beams  are 
arranged  as  shown  in  Fig.  36, 
and  a  cast-iron  bearing  plate 
3  feet  6  inches  square  is  used 
under  the  column.  The  dis- 
tance between  the  centers  of  outer  beams  in  upper  tier  is  made  3 
feet,  thus  making  the  value  of  L—B  for  both  tiers  equal  to  7  feet. 

Considering  the  upper  tier  of  beams  it  is  evident  that,  as  there 
are  five  beams,  each  one  must  sustain  a  load  of  400,000  pounds 
divided  by  5  or  3o,ooo  pounds,  equal  to  40  tons. 

Looking  down  column  headed  7  (Table  VI.)  the  nearest  value 
in  the  table  to  40  tons  is  43.6  which  indicates  a  15-inch  42-pound 
beam. 

For  the  lower  tier  of  beams  the  load  an  one  beam  will  be  found 
to  equal  400,000-^  ii  (the  number  of  beams  in  the  tier)  or  36,363 


L — B  being  taken  for  both  tiers. 


STONE 
FOOTING 

Fig.  36.    Steel  Beam  Grillage  Footing  under 
Column. 


SPREAD  FOUNDATIONS. 


67 


pounds.  This  amount  reduced  to  tons  equals  18.18  tons  and  from 
the  table  under  column  7  it  is  found  that  a  lo-inch  25-pound  beam 
has  a  strength  value  of  18.7  tons,  which  though  slightly  excessive 
is  the  economical  section. 

82.  COMBINED  FOOTINGS.  BASE-PLATES,  ETC.— 
The  deepest  beam  for  the  weight  should  always  be  used,  and  unless 
the  beams  in  the  upper  tier  have  considerable  excess  of  strength, 
the  two  outer  beams  should  be  heavy  beams. 


Two  Columns 


Grillage  Footing. 


When  the  footings  carry  iron  or  steel  columns  in  the  basement, 
as  is  generally  the  case,  a  cast-iron  or  steel  base-plate  should  be 
used,  as  shown  in  Figs.  37  and  38.  This  plate  should  be  bedded 
in  Portland  cement  directly  above  the  beams,  as  described  in 
Article  75. 

Two  and  even  four  columns  are  often  supported  on  one  footing, 
as  shown  in  Figs.  37  and  38.  In  such  cases  the  computation 
becomes  more  elaborate,  and  an  engineer  should  be  called  in  con- 
sultation, unless  the  architect  is  himself  sufficiently  familiar  with 
such  calculations. 

Fig.  39  shows  an  arrangement  in  which  a  built-up  base-plate  or 
girder  is  used  in  place  of  the  upper  tier  of  beams.  The  author 
believes  this  arrangement  much  better  than  that  shown  in  Figs.  36 
and  37,  though  the  cost  of  these  heavy  structural  steel  bases  is  very 
great  and  the  details  of  their  erection  very  exacting. 

In  placing  the  beams,  it  is  essential  that  they  be  arranged  sym- 
metrically under  the  base-plate,  as  otherwise  they  will  sink  more 
at  one  side  than  at  the  other.    When  several  unequally  loaded  col- 


68 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


iinins  rest  on  the  same  footing-,  the  ecjual  distribution  of  the  weight 
on  the  soil  becomes  a  difficnU  problem. 

C.    TIMBER  FOOTINGS 

83.  TLAIBER  FOOTINGS  IN  GENERAL.— For  biiildincrs 
of  moderate  height  timber  may  be  used  to  give  the  necessary  spread 
to  the  footings,  j>j-ovided  that  water  is  always  present.  The  foot- 
ings should  be  built  by  covering  the  bottom  of  the  trenches,  which 
should  be  perfectly  level,  with  2-inch  planks  laid  close  together  and 
longitudinally  in  the  direction  of  the  wall.  Across  these,  heavy 
timbers  should  be  laid,  spaced  al^out  12  inches  on  centers,  the  size 


Fig.  38.    Four  Columns  on  One  Grillage  Footing. 

of  the  timbers  being  proportioned  to  the  transverse  stress.  On  top 
of  these  timbers  should  be  spiked  a  floor  of  3-inch  planks  of  the 
same  width  as  the  masonry  footings  which  are  laid  upon  them. 
A  section  of  such  a  fc^oting  is  shown  in  Fig.  40. 

All  of  the  timber  work  must^be  kept  below  low-water  mark,  and 
the  space  between  the  transverse  timbers  should  be  filled  with  sand, 
broken  stone  or  concrete.  The  best  woods  for  such  foundations  are 
oak,  Georgia  pine  and  Norway  pine.  Many  of  the  old  buildings  in 
Chicago  rest  on  timber  footings. 


SPREAD  FOUXDATIONS. 


Fig-  39-    Built-up  Base  for  Column. 


X.mck  FlanK. 

Fig.  40.    Timber  Spread  Footing. 


70 


BUILDING  CONSTRUCTION.  (Ch.  II) 


84.  CALCULATION  FOR  THE  SIZE  OF  THE  CROSS 
TIMBERS. — The  size  of  the  transverse  timbers  should  be  com- 
puted by  the  following  formula : 

Breadth  m  inches  =   (6) 

D^XA 

w  representing  the  bearing  power  in  pounds  per  square  foot ;  p,  the 
projection  of  the  beams  beyond  the  3-inch  planks  in  feet;  s,  the  dis- 
tance on  centers  of  beams  in  feet,  and  D,  the  assumed  depth  of  the 
beams  in  inches.  A  is  the  ''constant  for  strength,"  and  should  be 
taken  at  90  for  Georgia  pine,  65  for  oak,  60  for  Norway  pine  and 
55  for  common  white  pine  or  spruce. 

Example  I. — The  side  walls  of  a  given  building  impose  on  the 
foundation  a  pressure  of  20,000  pounds  per.  lineal  foot ;  the  soil  will 
support,  without  excessive  settlement,  only  2,000  pounds  to  the 
square  foot.  It  is  decided  for  economy  to  build  the  footings  as 
shown  in  Fig.  40,  using  Georgia  pine  timber.  What  should  be  the 
size  of  the  transverse  timbers? 

Solution. — Dividing  the  total  pressure  per  lineal  foot  by  2,000 
pounds,  we  have  10  feet  for  the  width  of  the  footings.  The  masonry 
footing  we  will  make  of  granite  or  other  hard  stone,  4  feet  wide, 
and  solidly  bedded  on  the  planks  in  Portland  cement  mortar.  The 
projection  p  of  the  transverse  beams  would  then  be  3  feet.  We 
will  space  the  beams  12  inches  on  centers,  so  that  s  =  i,  and  we  will 
assume  10  inches  for  the  depth  of  the  beams.   Then  by  formula  (6), 

u  '    ■    u       2  X  2000  X  9  X  I 

the  breadth  m  mches  =   =  4, 

100  X  90 

or  we  should  use  4  by  10- inch  timbers,  12  inches  on  centers.  If 
common  pine  timber  were  used  we  should  substitute  55  for  90,  and 
the  result  would  be  6^  inches. 

85.  BUILDINGS  ON  QUICKSAND.— When  building  on 
quicksand  it  is  often  advantageous  to  lay  a  floor  of  i-inch  boards 
in  two  or  more  layers  at  right  angles  to  each  other  on  which  to 
start  the  concrete  footings. 

.  86.  FOUNDATIONS  FOR  TEMPORARY  BUILDINGS.— 
When  temporary  buildings  are  to  be  built  over  a  compressible  soil, 
the  foundations  may,  as  a  rule,  be  constructed  more  ■  cheaply  of 
wood  than  of  any  other  material,  and  in  such  cases  the  durability 
of  the  timber  need  not  be  considered,  as  good  sound  timber  will 


MASONRY  WELLS. 


71 


last  two  or  three  years  in  almost  any  place  if  thorough  ventilation 
is  provided. 

The  World's  Fair  buildings  at  Chicago  (1893)  were,  as  a  rule, 
supported  on  timber  platforms,  proportioned  so  that  the  maximum 
load  on  the  soil  would  not  exceed  1^4  tons  per  square  foot.  Only 
in  a  few  places  over  ''mud  holes"  were  pile  foundations  used. 

The  platform  foundations  consisted  of  *'3-inch  pine  or  hemlock 
planks,  with  blocking  or  transverse  beams  on  top,  to  distribute 
uniformly  over  all  the  planks,  the  pressure  from  the  loads,  and  to 
furnish  support  for  the  posts  which  carried  the  caps  supporting  the 
floor  joists  and  posts  of  the  building.  The  blocking  was  well 
spiked  to  the  platform  planks  and  posts,  and  the  caps  and  the  sills 
were  drift-bolted." 


Fig.  41.    Temporary  Timber  Column  Foundation.    World's  Fair  Buildings,  Chicago,  1893. 

Fig.  41  shows  the  general  arrangement  of  the  blocking  under  the 
posts. 

3.    MASONRY  WELLS 

87.  MASONRY  WELLS  UNDER  CITY  HALL,  KANSAS 
CITY,  MO. — When  it  is  necessary  to  support  very  heavy  buildings 
on  compressible  or  filled-in  soil,  where  piles  or  spread  footings  can- 
not be  used,  or  are  not  considered  desirable,  wells  of  masonry,  sunk 
to  bed-rock  or  hard-pan,  will  generally  prove  the  method  of  secur- 
ing an  efficient  foundation  which  comes  next  in  point  of  economy. 


72 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


The  wells  are  arranged  as  isolated  piers,  and  the  walls  of  the  super-  ^ 
structure  are  carried  on  steel  girders  resting  on  these  piers. 

The  manner  in  which  such  wells  or  piers  should  be  used  can  prob- 
ably be  best  explained  by  describing  those  under  the  City  Hall  of 
Kansas  City,  Mo.,  which  was  one  of  the  first  instances  in  which 
such  wells  were  used  in  this  country. 

"The  site  of  the  City  Hall  was  formerly  a  ravine  between  abrupt  bluifs. 
These  had  been  so  cut  away  and  levelled  as  to  leave  a  50-foot  filling  of  rub- 
bish under  two-thirds  of  the  building  and  a  solid  clay  bank  under  the  other 
third.  The  fill  was  made  by  a  public  dump.  Pile  foundations  were  objection- 
able on  account  of  the  dryness  of  the  fill  and  the  anticipated  tendency  of  the 
piles  to  rot  therein.  Ordinary  trenching  was  considered  too  expensive  and 
dangerous,  therefore  a  system  of  piers  was  chosen,  and  a  cylindrical  form 
was  adopted,  so  that  the  excavation  could  be  done  by  a  large  steam-power 
auger,  followed  by  a  3/16-inch  caisson  filled  with  vitrified  brick.  The  caissons 
were  made  in  5-foot  lengths  of  the  same  thickness  throughout,  the  joints  being 
made  with  3"x>^"  splice  plates,  riveted  to  the  inside  of  the  shell. 

"The  piers  were  of  vitrified  brick,  4  feet  6  inches  in  diameter,  laid  in 
hydraulic  cement  mortar,  grouted  solid  in  each  course,  and  well  bonded  in 
all  directions.  The  piers  were  sunk  to  bed  rock  of  oolitic  limestone,  8  feet 
thick,  and  capped  with  cast-iron  plates  (Fig.  42)  and  steel  I-beams,  which 
supported  the  walls.  To  the  top  of  the  beams  was  riveted  a  ^-inch  plate 
of  boiler  iron,  on  which  the  brickwork  of  the  walls  was  built,  as  shown  in 
Fig-  43- 

"Between  the  beams,  and  i  foot  on  each  side  and  underneath  them,  is  a 
concrete  filling,  so  that  the  beams  are  entirely  encased  in  masonry. 

"Piers  having  excessive  loads  are  reinforced  by  12-inch  Z-bar  columns 
resting  on  rock  bottom  (Fig.  44).  These  columns  pass  through  the  cast-iron 
caps,  so  that  the  loads  resting  on  the  columns  are  separate  from  those  on  the 
brick  piers  (an  essential  provision).  Essentially  the  whole  system  is  intended 
to  secure  the  direct  transmission  of  the  entire  weight  to  the  solid  rock  by  so 
arranging  the  interior  construction  that  each  subdivision  is  carried  by  an 
adequate  isolated  pier.  The  piers  are  of  uniform  size,  and  their  loads  are 
equalized  by  spacing  them  at  proportionate  distances  apart." 

88.  MASONRY  WELLS  UNDER  STOCK  EXCHANGE 
BUILDING,  CtllCAGO. — Another  instance  of  the  use  of  masonry 
wells  or  deep  piers  is  in  the  foundation  of  th%  Stock  Exchange 
building  in  Chicago. 

"The  foundation  is  generally  upon  piles  about  50  feet  long,  driven  into 
the  hard  clay  which  overlies  the  rock.  Next  to  the  Herald  Building,  however, 
which  adjoins  it,  wells  were  substituted,  lest  the  shock  of  the  pile  driver 
close  to  its  walls  should  cause  settlements  and  cracks.    A  short  cylinder, 

*  The  following  description  is  an  abstract  of  a  short  paper  presented  by  the  architect 
of  the  building,  Mr.  S.  E.  Chamberlain,  of  Kansas  City,  to  the  twenty-fourth  annual  con- 
vention of  the  American  Institute  of  Architects.  The  illustrations  were  prepared  in  the 
office  of  the  Engineering  Record  from  the  architect's  drawings.  Several  more  illustrations 
are  given  in  the  Engineering  Record  of  April  2  and  16,  1892. 


MJSOXRY  WELLS. 


73 


Figs.   4J,  43,   44.     Masonry   \\>lls  Under  City  Hall,   Kansas  City,  Mo. 


5  feet  in  diameter,  made  of  steel  plate,  was  first  sunk  by  hand,  reaching  below 
the  footings  of  the  Herald  Building.  Then  around  and  inside  the  base  of  the 
cylinder  sheet  piles,  about  35^2  feet  long,  were  driven,  and  held  in  place  by  a 
ring  of  steel  inside  their  upper  ends.  The  material  inside  the  sheeting  was 
excavated  and  a  similar  steel  ring  was  placed  inside  their  lower  ends.  By 
means  o*f  wedges  the  lower  ends  of  the  sheeting  were  forced  back  into  the 
soft  clay  until  another  course  could  be  driven  outside  the  lower  ring.  This 
operation  was  repeated  unril  the  excavation  had  reached  the  hard  clay  about 
40  feet  below  the  cellar.    In  this  material  the  excavation  was  continued  with- 


74 


BUILDING  CONSTRUCTION.  (Ch.  II) 


out  sheeting  in  the  form  of  a  hollow  truncated  cone  to  a  diameter  of 
feet,  and  the  entire  excavation  was  filled  with  concrete.    The  wells  are 
spaced  about  12  feet.    The  loads  upon  them  vary;  some  of  them  will  carry 
about  200  tons. 

"The  material  excavated  was  a  soft,  putty-like  clay  to  a  depth  of  40  feet, 
where  a  firm  clay  was  reached  deemed  capable  of  carrying  the  weight  pro- 
posed."* 

4.    CAISSON  FOUNDATION  CONSTRUCTION 

89.  GENERAL  DESCRIPTION.— Caissons  are  constructed  of 
timber  or  metal  and  are  made  cylindrical,  square,  or  rectangular  in 
section,  open  at  both  ends,  or  closed  at  the  top  or  bottom.  This 
construction  is  employed  where  it  is  necessary  to  penetrate  a  con- 
siderable depth  of  soft  soil,  permeated  with  water,  to  the  solid 
rock  or  hard-pan  beneath.  Caissons  are  named  after  the  manner  of 
their  use,  as  "open,"  ''erect,"  and  "inverted."  The  "open"  caisson 
is  simply  a  cylinder  or  open  box  made  of  planks,  timbers,  or  sheet- 
steel,  without  top  and  bottom.  It  is  sunk  by  excavating  inside,  and 
allowing  it  to  settle  by  its  own  weight,  or  by  a  load  on  a  platform 
constructed  upon  the  top.  The  sides  are  made  water-tight,  and  any 
water  coming  in  around  the  bottom  edge  or  through  the  soil  at  the 
bottom  is  pumped  out  by  hand,  steam  pump,  or  pulsometer. 

Caissons  constructed  with  water-tight  bottoms  are  seldom  used 
in  building  construction,  but  are  frequently  employed  in  building 
the  foundations  of  bridges  or  other  foundations  in  water.  When 
so  used,  they  are  towed  to  the  desired  position,  and  when  properly 
located,  and  guided,  are  sunk  by  being  filled  with  masonry  or  con- 
crete.   Such  caissons  are  usually  called  "erect"  caissons. 

90.  INVERTED  CAISSONS.— The  "inverted"  caissons  are 
the  ones  most  frequently  and  successfully  used  in  the  construction 
of  important  foundations  carried  to  hard-pan  or  solid  rock  through 
strata  of  soft  soil.  They  take  the  form  of  water-tight  boxes  or 
cylinders.  Closed  at  the  top  and  open  at  the  bottom,  they  are 
strongly  braced,  and  are  usually  made  of  steel  plates,  though  some- 
times constructed  of  heavy  timbers.  The  operation  of  sinking  them 
consists  in  building  masonry  upon  the  top,  and  in  carrying  on  the 
excavation  inside  and  around  their  cutting-edge. 

91.  THE  VACUUM  SYSTEM.— Two  systems  are  successfully 


*  "Foundations  of  High  Buildings."  W.  R.  Hutton.  Read  before  the  Congress  of 
Architects  at  Chicago,  1893. 


CAISSON  FOUNDATION  CONSTRUCTION. 


75 


used  in  sinking  ''inverted"  caissons,  namely,  the  ''vacuum"  system, 
and  the  "plenum"  system. 

In  the  former  the  air  is  exhausted  from  the  interior  of  the  caisson 
and  the  excess  of  atmospheric  pressure  upon  its  top  assists  >  in 
forcing  it  downward ;  while  on  <  ccount  of  the  partial  vacuum  inside, 
the  water  around  the  excavation  flows  rapidly  under  the  edge  and 
into  the  caisson,  thus  loosening  the  soil  and  allowing  it  to  be  drawn 
out  with  the  water. 

92.  THE  PLENUM  SYSTEM.— The  "plenum"  system  is  the 
one  generally  used,  however.  In  this  system  water  is  prevented 
from  flowing  into  the  caisson  by  creating  inside  of  it  an  air  pressure, 
the  excess  of  which  over  that  of  the  atmosphere  is  sufficient  to 
equalize  the  pressure  of  the  water  outside.  This  air  pressure  is  pro- 
vided by  powerful  air-pumps.  The  workmen  enter  the  caisson 
through  an  air-lock,  placed  in  a  tube,  or  cylinder,  leading  from  the 
caisson,  and  consisting  of  an  air-tight  conipartment  with  two  doors. 
(See  Fig.  49.)  In  operating  the  air-lock,  the  workman  enters  through 
the  first  door,  or  trap,  and  closes  it,  allowing  the  air  under  pressure 
in  the  caisson  to  flow  in  slowly  until  the  pressure  in  the  air-lock  is 
equal  to  that  in  the  caisson,  when  the  door  to  the  caisson  is  opened 
and  the  workman  allowed  to  enter.  If  the  air  were  suddenly  let 
into  the  air-lock,  the  physical  strain  upon  the  men  would  be  severe 
and  dangerous. 

The  material  from  the  excavation  is  usually  hoisted  in  buckets, 
operated  through  air-locks,  and  the  work  is  carried  on  in  this  way 
until  the  caisson  has  reached  the  required  depth,  when  it  is  filled 
with  concrete  or  masonry,  and  the  piers  constructed  upon  the  top. 

93.  CAISSONS  IN  THE  MANHATTAN  LIFE  INSUR- 
ANCE CO.'S  BUILDING,  NEW  YORK.— Although  caissons 
have  been  for  some  time  extensively  used  in  constructing  the 
foundations  of  bridge  piers,  they  were  not,  until  a  relatively 
recent  date,  used  for  the  foundations  of  buildings  in  this  country. 
The  first  instance  was  that  of  the  building  for  the  Manhattan  Life 
Insurance  Company,  near  the  foot  of  Broadway,  New  York  City ; 
Messrs.  Kimball  &  Thompson,  Architects;  Charles  O.  Brown,  Con- 
sulting Engineer. 

The  method  there  employed  proved  perfectly  satisfactory,  and  cost 
only  about  8  or  9  per  cent  of  the  estimated  cost  of  the  building.  The 
following  is  a  short  description  of  the  manner  in  which  the  founda- 


76  BUILDING  CONSTRUCTION.  (Ch.  II) 


tions  were  constructed  and  the  superstructure  supported  thereon,  in 
this  early  example:'^ 

"The  building  occupies  an  area  of  about  8,200  square  feet,  and  is 
seventeen  stories  high  on  Broadway  and  eighteen  on  New  Street.  The 
height  from  the  Broadway  curb  to  the  parapet  of  the  main  room  is  242  feet, 
and  the  dome  and  tower  rises  108  feet  above  the  parapet.  All  the  walls, 
together  with  the  iron  floors  and  roof  (which  are  very  heavy),  are  directly 
supported  by  thirty-four  cast-iron  columns,  which  sustain  an  estimated  weight 
of  about  30,000  tons. 

"The  great  height  and  massive  metal  and  masonry  construction  impose 
enormous  loads  on  the  foundations,  amounting  to  as  much  as  2CO  tons  for 
some  single  columns,  and  giving  about  7,300  pounds  per  square  foot  over 
the  whole  area  of  the  lot.  This  enormous  weight  could  not  be  safely  carried 
on  the  natural  soil,  which  is  essentially  of  mud  and  quicksand  to  the  bed 
rock,  which  has  a  fairly  level  surface  about  54  feet  below  the  Broadway  street 
level.  Above  this  rock  the  water  percolates  very  freely,  standing  at  a  level 
of  about  22  feet  below  the  Broadway  street  line,  and  therefore  making  exca- 
vations below  this  plane  difficult  and  costly.  If  piles  had  been  driven  as  close 
together  as  the  city  regulations  permit — /.  e.,  30  inches  center  to  center  over 
the  whole  area,  about  1,323  might  have  been  placed,  and  would  have  carried 
an  average  load  of  45,300  pounds  each,  which  was  inadmissible,  the  statute 
laws  of  New  York  allowing  only  40,000  pounds  each  on  piles  2  feet  6  inches 
apart  and  with  a  smallest  diameter  of  5  inches. 

"Special  foundations  were  therefore  necessary,  and  it  was  imperative  that 
their  construction  and  duty  should  not  jeopardize  nor  disturb  the  existing 
adjacent  heavy  buildings  which  stand  close  to  the  lot  lines.  On  the  south  side 
the  six-story  Consolidated  Exchange  building  is  founded  on  piles  which  are 
supposed  to  extend  to  the  rock.  On  the  north  the  foundations  of  a  four-story 
brick  building  rest  on  the  earth  about  28  feet  above  the  rock,  and  were 
especially  liable  to  injury  from  disturbances  of  the  adjoining  soil,  which  was 
so  wet  and  soft  as  to  be  likely  to  flow  if  the  pressure  was  much  increased  by 
heavy  loading  or  diminished  by  the  excavation  of  pits  or  trenches. 

"In  view  of  these  conditions  it  was  determined  to  carry  the  foundations 
on  solid  masonry  piers  down  to  bed  rock.  The  construction  of  the  piers  by 
the  pneumatic  caisson  process  was,  after  careful  consideration  by  the  archi- 
tects, backed  by  opinions  from  prominent  bridge  engineers  as  to  its  feasibility, 
adopted, 

"The  smaller  caissons  were  received  complete  and  the  larger  ones  in 
convenient  sections,  bolted  together  when  necessary,  and  located  in  their  exact 
horizontal  positions,  calked  and  roofed  with  heavy  beams  to  form  a  platform, 
on  which  the  brick  masonry  was  started  and  built  up  for  a  few  feet  before 
the  workmen  entered  the  excavating  chamber  and  began  digging  out  the 
soil.  The  removal  of  the  soil  allowed  the  caissons  to  gradually  sink  to  the 
rock  below  without  disturbing  the  adjacent  earth,  which  was  kept  from  flowing 
in  by  maintaining  an  interior  pneumatic  pressure  slightly  in  excess  of  the 


*  Abstract  from  a  very  full  description,  with  ten  illustrations,  published  in  the 
Engineering  Record  of  January   20,  1894. 


78 


BUILD  I  KG  COXSTKUCTIOX.. 


(Ch.  II) 


■outside  hydrostatic  pressure  due  io  tlie  distance  of  the  hottoOT  of  the  caisscyn 
below  the  water  line. 

''The  adjacent  buildings  were  shored  up  at  the  outset  and  scrupulouisty 
watched,  observations  being  made  to  determine  any  possible  displacemient  or 
injury  of  their  walls,  which  were  not  seriously  damaged,,  though'  the  pressure 
they  exerted  on  the  yielding  soil  tended  to  deflect  the  caissons  which  were 
sunk  within  a  foot  of  them.  They  were  kept  in  position  by  excess  of  loading 
and  excavating  on  the  edges  that  tended  to  be  highest..  The  caissons  encoun- 
tered boulders  and  other  obstructions,  and  were  sunk  through  the  fine  soil 
and  mud  at  an  average  rate  of  4  feet  per  day.  No  blasting  was  required  until 
the  bed  rock  was  reached  and  levelled  off  under  the  edges  and  stepped  intO' 
horizontal  surfaces  throughout  the  extent  of  the  excavating  chamber.  Usually 
'One  caisson  was  being  sunk  while  another  was  being  prepared,,  there  being  only 
one  time  when  air  pressure  was  simultaneously  maintained  in  two  caissons. 
Generally  about  eight  days  were  required  to  sink  each  caisson." 


Fig.  46.     The  Manhattan  Life  Insurance  Building,  New  York  City.    Transverse  Section. 

PUBLISHED  BY  CONSENT  0-  THE  ENGINEERING  RECORD 


The  first  caisson  was  delivered  at  the  site  April  13,  1893,  and  the  last 
pier  was  completed  August  13,  1893. 

''After  the  caissons  were  sunk  to  bed  rock,  and  the  surface  cleared  and 
dressed,  the  excavating  chambers  and  shafts  were  rammed  full  of  concrete, 
made  of  i  part  Alsen  Portland  cement,  2  parts  sand  and  4  parts  of  stone, 
broken  to  pass  through  a  2^-inch  ring.  The  superimposed  piers  were  built 
of  hard-burned  Hudson  River  brick,  laid  in  mortar  composed  of  i  part  Little 
'Giant  cement  to  2  parts  sand." 

Fig.  45  is  a  plan  showing  the  piers,  all  of  which,  except  P,  which  is  built 
on  twenty-five  piles,  are  founded  on  caissons  of  the  same  size,  and  the  bol- 
sters on  top  of  them,  together  with  the  girders  and  the  columns,  which  are 
indicated  by  solid  block  cross  sections. 


CAISSOy  FOUKDATIOX  COXSTRUCTIOX .  79 

"Cylindrical  caissons  are  the  most  convenient  and  economical,  and  would 
have  been  used  throughout  if  the  conditions  had  permitted,  but  the  positions 
of  the  columns  and  the  necessity  of  distributing  the  load  along  the  building 
lines  and  other  considerations  determined  the  use  of  rectangular  ones,  except 
in  four  cases."  All  the  caissons  were  11  feet  high,  made  of  Yi-'mch  and 
•>^-inch  plates  and  6  by  6-incli  angle  framework,  stiffened  with  7-inch  bulb- 
angles,  vertical  brackets  and  reinforced  cutting  edges. 

The  columns  supporting  the  outer  side  walls  of  the  buildings  were  located 
so  near  the  building  line  that  they  were  near  or  beyond  the  outer  edge  of  the 
foundation  piers,  as  shown  in  Fig.  45,  so  that  if  they  had  been  directly  sup- 
ported thereon  they  would  have  loaded  them  eccentrically  and  produced  unde- 
sirable irregularities  of  pressure.  This  condition  was  avoided  and  the  weights 
transmitted  to  the  centers  of  the  piers  by  the  intervention  of  heavy  plate- 
girders,  which  supported  the  columns  in  the  required  positions  and  transferred 
their  weights  to  the  proper  bearings  above  the  piers.  From  these  bearings  the 
load  was  distributed  over  the  whole  area  of  the  masonry  by  special  steel 
bolsters. 

Fig.  46  is  a  transverse  section  at  D-H-M,  Fig.  45,  showing  the  quadruple 
girder  C,  17-18-19,  and  the  manner  in  which  it  supports  columns  23  and  33. 
The  cantilever  is  made  continuous  across  the  building,  with  intermediate 
supports  under  columns  21  and  22. 

Soon  after  this  pneumatic  caisson  foundations  were  used  in  the 
construction  of  the  American  Surety  building,  Xew  York,  a  full 
description  of  which  is  given  in  the  Engineering  Record  of  July  14,. 
1894.  Caisson  foundations,  whether  in  the  shape  of  wells  or  in  the 
pneumatic  form,  should  be  used  only  under  the  advice  or  direction 
of  a  competent  engineer. 

94.  CAISSONS  IN  THE  SINGER  BUILDING  AND  THE 
UNITED  STATES  EXPRESS  COMPANY'S  BUILDING, 
NEW  YORK. — Several  interesting  examples  of  recent  foundation 
construction,  in  which  the  pneumatic  caisson  has  been  successfully 
employed,  are  to  be  found  in  the  Singer  building  and  in  the  L^nited 
States  Express  Company's  building,  both  located  in  New  York 
City. 

Beneath  the  Singer  building  it  was  necessary  to  excavate  to  bed- 
rock, found  at  a  depth  of  90  feet  below  the  curb.  This  bed-rock 
was  overlaid  with  a  stratum  of  hard-pan  about  15  feet  deep.  The 
foundation  plan  of  the  building  consists  of  rectangular  and  cylindri- 
cal piers  of  concrete,  arranged  as  shown  in  Fig.  47,  all  of  these 
piers  being  constructed  by  means  of  pneumatic  caissons.  As  the 
Singer  building  is  41  stories  in  height,  with  a  tower  612  feet  above 
the  street  level,  the  load  upon  the  foundations  is  very  great,,  amount- 
ing to,  approximately,  27  tons  per  square  foot,  and  including  the 


8o 


BUILDING  CONSTRUCTION. 


(Cii.  1. 


r-r 


+ 


4- 


T 


4- 


+ 


Us.-. 

© 


©  |h.'--H  E^!3 


0 


■ft  nil  a 


4- 

A- 

+ 


t 

t 

+ 

> 

;'aV»/' 

Fig.   47*    Plan   of   Caisson   and   Pier   Foundation,    Singer   Building,   New  York. 

load  due  to  wind  pressure,  the  full  dead  load  and  about  6o  per  cent 
of  the  maximum  live  load. 

Fig.  48  shows  the  finished  concrete  piers  constructed  by  means 
of  the  caissons,  and  supporting  the  steel  frame  and  curtain-walls 
of  the  building  along  the  party-line,  with  the  interior  column  sup- 
port carried  some  distance  below  the  basement  floor  level. 

In  the  construction  of  the  United  States  Express  Company's 
building,  which  is  a  23-story  structure,  it  was  necessary  to  use* 
pneumatic  caissons  on  account  of  the  fluid  character  of  the  soil, 
made  treacherous  by  the  tidal  waters  of  the  Hudson  River.  The 
material  found  on  the  site  of  this  building  consisted  of  9  feet  of 
earth,  loam  and  fill,  and  an  average  of  18  feet  of  quicksand  over- 
lying a  stratum  of  hard-pan  14  feet  thick;  bedrock  was  found  at  a 
depth  of  41  feet  below  the  curb,  and  to  this  it  was  necessary  to 
extend  the  foundations. 

For  the  construction  of  this  building,  caissons  or  working  cham- 
bers were  provided,  consisting  of  bottomless  boxes,  rectangular  in 
cross-section  and  about  6  feet  wide,  with  a  minimum  length  of  35 
feet  4  inches,  and  a  width  of  6  feet.  The  walls  of  these  caissons 
were  built  up  of  six  courses  of  timber,  which  were  secured  by 
%-inch  drift-bolts  2  feet  long,  and  tied  together  vertically  by  i-inch 


*  From  Architects'  and  Builders'  Magazine,  January,  1907. 


CAISSOX  FOUXDATIOX  COXSTRUCTION ,  8t 


Fig.  48*     Section  of  Caisson  and  Pier  Foundation,  Singer  Building,  New  York. 


screw-rods,  placed  3  feet  apart ;  and  the  cutting  edge  was  provided 
with  a  6  by  4-inch  steel  angle.  The  heaviest  caisson  weighed  in 
the  neighborhood  of  10  tons,  and  was  large  enough  for  six  men 
to  work  inside  of  it;  a  roof  was  formed  over  it  with  ij^-inch 
tongued-and-grooved  boards,  and  connected  with  this  was  a  steel 
tube  or  shaft.  The  shaft  was  surmounted  by  what  is  known  as 
the  *'Moran"  air-lock.  When  the  shaft  or  working  tube  was  in 
place,  two  lo-feet  sections  of  temporary  wooden  forms  were  built 
upon  the  top  of  the  caisson,  a  layer  of  cement  mortar  6  inches 
thick  was  spread  over  the  temporary  loof,  and  upon  this  24  inches 
of  I,  2  and  4  concrete  was  placed  and  allowed  to  set  for  24  hours. 
This  construction  formed  a  concrete  slab  strong  enough  to  carry 
the  concrete  forming  the  pier.  The  lo-feet  sections  were  then 
filled  with  concrete,  and  when  this  had  set,  additional  forms  were 
raised  and  more  concrete  put  in  place.    As  the  caisson  was  brought 


*Fro!n  Architects'  and  Builders'  Magazine,  January,  1907. 


82  BUILDING  CONSTRUCTION,  (Ch.  II) 


to  the  water  level,  compressed  air  was  pumped  into  it,  or  into  the 
bottom  working  chambers,  to  expel  the  water  from  the  lower  or 
cutting  edge,  and  to  allow  the  work  of  excavation  to  proceed  inside. 
Thus  undermined,  the  caisson  sank  by  the  great  weight  of  the  con- 
crete above,  and  where  necessary  the  weight  was  augmented  by 
piling  pig-iron  on  top.  When  the  caisson  reached  bed-rock  and  a 
pier  of  concrete  extended  from  its  roof  to  the  top  of  the  pier,  the 
interior  of  the  working  chamber  and  the  shaft  connecting  the  latter 
with  the  outer  air  were  filled  with  rich  concrete. 

In  operating  the  caisson  construction  in  both  this  building  and 
the  Singer  building,  the  above  mentioned  Mbran  air-lock  was 
employed.    This  air-lock  is  illustrated  in  Fig.  49,  and  is  the  inven- 

o 


Fig.  49.*    Section  of  Moran  Air-Lock, 


tion  of  Mr.  Daniel  C.  Moran.  In  operation  it  is  similar  in  principle 
to  the  ordinary  river-lock,  in  that  one  door  is  always  closed,  thus 
maintaining  the  pressure  in  the  working  chamber  with  a  minimum 
of  leakage.  From  the  figure  it  will  be  observed  that  the  two  doors 
of  the  air-lock  are  hinged  and  counter-weighed,  allowing  them  to 
be  operated  readily  when  the  pressure  is  relieved  or  equalized ;  and 
they  are  made  air-tight  by  means  of  heavy  rubber  gaskets  around 
the  edge.    In  order  to  enter  the  caisson  the  workman  descends  the 


*  From  Architects'  and  Builders'  Maga::ine,  January,  1907. 


CANTILEVER  FOUNDATION  CONSTRUCTION.  83 


shaft  and  passes  through  the  upper  opening  into  the  chamber  or 
air-lock,  when  the  door  is  closed  and  a  valve  opened,  allowing  the 
air  to  flow  from  the  caisson  or  lower  part  of  the  shaft  into  the 
chamber  or  air-lock,  and  to  thus  equalize  the  air  pressure  so  that 
the  lower  door  may  be  opened  and  access  had  to  the  lower  part  of 
the  tube  and  thence  to  the  caisson.  In  hoisting  the  dirt  or  silt  the 
process  is  reversed  by  hauling  the  bucket  up  into  the  air-lock,  the 
hoisting  rope  passing  through  a  stuffing-box  in  the  upper  door. 
By  closing  the  lower  door  the  upper  one  may  be  opened  and  the 
bucket  hoisted  from  the  lock  and  up  the  shaft.  The  loss  of  air  in 
each  operation  is  the  volume  contained  in  the  air-lock  or  chamber 
in  the  shaft  between  the  two  doors. 

~  95.  FOUNDATIONS  OF  HIGH  BUILDINGS.— In  prepar- 
ing the  foundations  for  high  buildings  the  same  principles  apply  as 
for  other  buildings,  except  that  as  the  loads  on  the  foundations 
are  so  much  greater,  the  footings  must  be  proportioned  with  the 
utmost  care. 

When  building  on  firm  soils  it  is  only  necessary  to  observe  care- 
fully all  the  precautions  given  in  Chapter  I. ;  and  when  building  on 
compressible  soils  one  of  the  methods  described  in  this  chapter 
should  be  employed,  always,  however,  under  the  advice  of  an 
experienced  engineer. 

5.    CANTILEVER  FOUNDATION  CONSTRUCTION 

96.  GENERAL  DESCRIPTION.— In  thickly  built-up  dis- 
tricts of  cities,  where  the  ground  is  of  great  value  and  where  every 
available  square  foot  of  space  must  be  utilized,  it  is  necessary  to 
build  close  to  the  party-lines.  Frequently  the  party-walls  of  the 
adjoining  buildings  are  entirely  inadequate  for  the  support  of  the 
floor  systems  of  the  newer  heavy  structure,  so  that  new  founda- 
tions must  be  provided.  If  the  building  to  be  erected  is  many 
stories  high,  foundations  of  considerable  area  are  required.  Such 
foundations,  under  the  City  Laws  and  Ordinances,  must  be  entirely 
within  the  party-line  of  the  owner's  property,  unless  it  is  proposed 
to  underpin  and  shore  the  old  building,  and  erect  a  party-wall  for 
both  the  new  and  old  structure.  This  is  not  always  desirable,  on 
account  of  the  expense  and  the  likelihood  of  difficulties  with  the 
adjoining  owners  and  tenants. 

By  building  the  footing  entirely  inside  of  the  party-line,  as 
shown  in  Fig.  50,  the  line  of  action  of  the  weight  JV  does  not  coin- 


84 


BUILDING  CONSTRUCTION.  (Ch.  II) 


1 

1 

1 

1 

r 

J 

p 

cide  with  the  Hue  of  action  of  the  resultant  of 
the  pressure  P  from  the  foundation  soil,  so  that 
there  is  a  tendency  to  throw  outward  the  walls 
of  the  building  and  to  cause  unequal  pressures 
upon  the  soil.  In  order  to  provide  a  foundation 
which  will  give  an  equal  pressure  upon  each, 
square  foot  of  soil,  the  cantilever  system  of 
foundation  construction  shown  in  Fig.  51  is  used. 
In  this  figure  the  existing  wall  against  which  it 
is  desired  to  build  is  shown  at  a,  and  the  wall 
column  and  the  curtain-wall  of  the  new  structure 
supported  by  the  cantilever  beam  is  indicated  at 
h.  By  arranging  the  footing  c  under  the  canti- 
lever beam  as  shown,  the  undermining  of  the 
old  wall  of  the  adjoining  building  is  avoided  and  a  uniform  pres- 
sure is  brought  to  bear  on  the  soil  beneath  the  footing  c.  As 
the  weight  of  the  curtain-wall,  and  of  one-half  of  the  floor  loads  of 
all  the  stories  between  columns  b  and  d,  is  concentrated  on  the  over- 
hanging  end  of  the  cantilever,  there  is  a  lifting  tendency  on  the 
column  d ;  so  that,  for  stability  of  construction,  the  product  of  the 
force  represented  by  the  weight  W  by  its  lever  arm  x  must  equal 
the  product  of  the  force  represented  by  the  weight  ll\  by  its  lever 
arm  x^. 

From  Fig.  51  it  will  be  observed  that  the  footings  are  of  concrete 


Fig.  50.  Footing  In- 
side of  Party  Line. 
Center  of  Pressure 
Outside  of  Center  of 
Base. 


Fig.  51.    Examples  of  Cantilever  Foundation  Construction.    Loss  of  Head-room. 


CANTILEVER  EOUNDATIOX  COXSTRUCTIOX .  85 


and  that  the  weight  *is  distributed  over  them  by  means  of  the  grill- 
age beams.  Usually  a  heavy  cast-iron  or  structural  steel  bed-plate 
or  bearing-plate  transciiits  the  load  at  the  overhanging  end  of  the 
cantilever  to  the  grillage,  as  at  c.  The  beams  marked  g  are  framed 
in  between  the  several  cantilever  beams  or  girders,  and  support 
what  would  in  this  instance  be  the  basement  floor,  as  there  is,  with 
this  construction,  insufficient  head-room  below  the* bottom  of  the 
cantilever  beams  to  form  a  basement. 

97.  CANTILEVER  CONSTRUCTION  WITH  EXTENDED 
HEAD-ROOM.— The  type  of  cantilever  foundation  just  described 
provides  the  cantilever  beams  or  girders  directly  over  and  not  far 
removed  from  the  foundation  footing  and  immediately  under  the 
basement  floor.  Such  construction  results  in  a  considerable  waste 
of  head-room  or  vertical  distance,  which  is  not  always  advisable,  so 
that  the  cantilever  construction  shown  in  Fig.  52  is  frequently  em- 
ployed. In  this  illustration  the  cantilever  forms  the  main  supporting 
member  of  the  first  floor  construction,  and  consists  of  a  built-up 
plate-girder  of  box  section,  as  at  a.    Upon  the  overhang  end,  where 


Fig.  52.    Example  of  Cantilever  Foundation  Construction.  Bacenient  Head-room  Retained. 


86 


BUILDING  CONSTRUCTION. 


(Ch.  II) 


it  is  strongly  braced  against  buckling  by  means  of  stiffeners  or 
angles,  the  wall  columns  and  curtain-walls  are  supported  as  at  b. 
The  cantilever,  instead  of  being  supported  almost  directly  upon  the 
foundation,  is  carried  by  a  structural  steel  column,  some  distance 
inside  of  the  party-line,  and  this  column  in  turn  is  supported  by  the 
grillage  foundation,  as  at  c.  The  other  end  of  the  cantilever  girder 
is  secured  to  the  interior  structural  steel  column  d.  Where  the  load 
upon  the  overhanging  end  of  the  cantilever  is  excessive  and  the 
leverage  is  sufficient  to  cause  too  great  a  lifting  tendency  upon  the 
interior  column  d,  the  latter  must  be  designed  with  a  heavy  founda- 
tion and  anchor-bolts,  so  that  there  will  be  sufficient  resistance  to 
this  upward  action. 

In  the  illustration,  Fig.  52,  the  bottom  of  the  foundation  footing 
under  the  wall  of  the  adjoining  building  does  not  extend  down  to 
the  depth  of  the  new  basement  floor  level ;  so  that,  in  order  to 
carry  on  the  excavation,  steel  sheet-piling  is  driven  along  the  wall 
line  to  prevent  the  earth  from  sliding  from  under  the  old  footings, 
as  at  e.  This  sheet-piling  is  afterwards  backed  up  with  concrete,, 
which  is  incorporated  with  the  concrete  of  the  grillage  footing,  and  ^ 
forms  an  adequate  retaining-wall  to  prevent  the  earth  under  the  old 
wall  from  being  disturbed.  While  the  ledge  of  concrete,  as  at  / 
in  the  figure,  along  the  basement  wall  can  hardly  be  considered  as 
objectionable,  this  construction  may  be  done  away  with  by  under- 
pinning the  old  wall. 

Cantilever  foundation  construction  involving  the  use  of  struc- 
tural steel  is  always  expensive  but  sometimes  unavoidable.  In  many 
instances  when  it  must  be  used,  the  cost  may  be  materially  reduced 
by  using  footings  and  foundation  constructions  of  reinforced  con- 
crete. 


Chapter  III. 


Masonry  Footings    and  Founda- 
tion Walls,  Shoring  and 
Underpinning 

^  I.    MASONRY  FOOTINGS 

98.  PURPOSE  OF  FOOTINGS.— Footings  under  walls  are 
used  for  two  purposes:  i.  To  spread  the  weight  over  a  greater 
area.  2.  To  add  to  the  stability  of  the  wall.  Under  buildings  of 
only  two  or  three  stories,  the  latter  function  is  generally  the  more 
important. 

All  walls  should  therefore  have  a  footing  or  projecting  course  at 
the  bottom  of  brick,  stone  or  concrete. 

The  width  of  the  footings  should  be  at  least  12  inches  wider 
than  the  thickness  of  the  wall  above,  and  should  also  be  such  that 
the  pressure  per  square  foot  under  the  footings  will  not  exceed 
the  safe  bearing  power  of  the  soil  nor  of  the  material  on  which  it 
rests.   (See  Article  17.) 

99.  CONCRETE  FOOTINGS.— For  nearly  all  classes  of 
buildings  built  on  solid  ground,  cement  concrete  makes  probably 
the  best  material  for  the  bottom  footing  course,  especially  for  the 
money  expended.  Concrete  possesses  the  advantage  over  large 
blocks  of  stone  of  having  considerable,  transverse  strength,  so  that 
when  fully  hardened  it  is  much  like  a  wide  beam  laid  on  top  of  the 
ground  under  the  walls ;  and  should  a  weak  spot  occur  in  the 
ground  under  the  footing,  the  latter  would  probably  have  sufficient 
transverse  strength  to  span  it  if  it  were  not  very  large.  Concrete 
must  also  necessarily  bear  evenly  over  the  bottom  of  the  trenches, 
so  that  there  can  be  no  cavities,  as  is  sometimes  the  case  with  stone 
footings.  In  localities  where  large  blocks  of  granite  or  flagging 
cannot  be  cheaply  procured,  concrete  makes  much' the  cheapest 
footing. 

As  concrete  is  now  available  in  all  localities,  many  architects  and 
engineers  believe  it  advisable  to  use  it  in  place  of  bricks  for  foot- 

87 


* 


88 


BUILDING  CONSTRUCTION 


(Ch.  Ill) 


ings.  While  good  hard-burned  bricks  are  very  durable  when  used 
above  ground,  they  are  not  so  durable  when  used  under  ground ; 
and  in  the  latter  case  there  is  a  tendency  to  deteriorate,  due  prob- 
ably to  the  continuous  saturation  and  to  the  action  of  frost. 

In  stiff  soil,  trenches  for  the  concrete  footings  should  be  dug 
below  the  general  level  of  the  excavation  and  of  the  exact  width 
of  the  footings,  so  that  when  the  concrete  is  put  in  and  tamped  it 
will  bear  against  the  sides  as  well  as  on  the  bottom  of  the  trenches. 
In  sandy  soils  this  of  course  cannot  be  done,  and  planks  must  be 
set  up  and  held  in  place  by  stakes  to  form  the  sides  of  the  trenches. 
After  the  cement  has  set,  but  not  before,  the  planks  ma}*  be 
removed. 

Concrete  for  footings  should  be  mixed  in  the  proportion  of  i 
part  of  cement  to  2  parts  of  sand  and  4  parts  of  stone  for  natural 
cements,  and  i  to  2^  and  5  for  Portland  cements.  The  thickness 
of  the  concrete  should  be  one-fourth  of  its  width,  and  never  less 
than  12  inches,  except  under  very  light  buildings.  The  concrete 
should  be  put  in  in  layers  about  6  inches  thick.  If  the  footing  is 
considerably  wider  than  the  wall  it  may  be  stepped  in  by  setting 
up  planks  to  hold  the  upper  layers  of  concrete,  or  a  stone  footing 
of  proper  width  may  be  placed  on  top  of  the  concrete,  as  in  Fig.  53. 
The  latter  is  apt  to  give  the  best  results. 


Fig.   53.    Concrete  and  Stone  Footing.  Fig.    54.  Two-Course 

Stone  Footing. 

For  the  manner  of  mixing  the  concrete  see  Chapter  X.  For 
width  of  offsets  see  Article  103. 

100.  BUiLDING  LAWS  REGARDING  CONCRETE  FOOT- 
INGS.— The  building  laws  of  several  of  the  principal  cities  agree 
closely  with  the  New  York  building  laws  in  their  requirements  for 
concrete  footings.  In  New  York  concrete  for  footings  must  consist' 
of  at  least  i  part  of  Portland  cement  to  2  parts  of  sand  and  5 


MASONRY  FOOTINGS. 


89 


parts  of  broken  stone,  and  the  stone  must  be  of  such  a  size  that  it 
will  pass  through  a  2-inch  ring.  Clean  gravel  in  the  same  propor- 
tions may  be  substituted  for  the  stone.  The  footing  course  must  in 
all  cases  be  at  least  12  inches  in  thickness,  and  at  least  12  inches 
wider  than  the  bottom  width  of  the  wall,  or  of  the  piers,  columns 
or  posts.  Should  the  projection  of  the  footing  be  subjected  to 
undue  transverse  stress,  the  thickness  must  be  increased  so  as  to 
safely  carry  the  load.  A  deviation  from  the  law  with  regard  to  the 
12-inch  thickness  may  be  made,  however,  at  the  discretion  of  the 
Commissioner  of  Buildings,  where  the  structure  is  small  or  the 
loads  are  light. 

loi.  STONE  FOOTINGS. — For  buildings  of  moderate  height 
stone  footings  are  generally  the  most  economical,  and  if  they  are 
carefully  bedded,  answer  as  well  as  concrete. 

If  practicable,  the  bottom  footing  course  should  consist  of  single 
stones  of  the  full  width  of  the  footing,  and  the  thickness  of  the 
stones  should  be  about  one-fourth  of  their  width,  depending  much, 
however,  upon  the  kind  of  stone.  If  stone  of  sufficient  width  cannot 
be  obtained,  the  stone  may  be  jointed  under  the  center  of  the  wall, 
and  a  second  course  consisting  of  a  single  stone  placed  on  top,  as 
shown  in  Fig.  54. 

In  order  that  the  projection  of  a  stone  in  a  footing  course  shall 
have  sufficient  transverse  resistance,  the  length  of  the  part  of  the 
stone  beneath  the  upper  course  should  be  at  least  twice  the  pro- 
jection of  the  stone;  that  is,  a  stone  in  a  footing  course  should  not 
have  a  projection  greater  than  one-third  of  its  length.  If  shorter 
stones  than  these  are  used,  the  projecting  courses  of  the  footings 
are  apt  to  break  off,  or  to  be  torn  from  their  beds. 

It  is  good  practice  in  the  design  of  stone  footing  courses  to  keep 
the  angle  between  the  horizontal  and  a  line  drawn  through  the  upper 
outside  edges  of  the  projecting  courses  not  less  than  60  degrees, 
or  to  make  the  projection  such  that  it  will  not  be  greater  than  one- 
half  the  thickness  of  the  course.  Where  this  rule  is  followed,  the 
footing  is  not  likely  to  fail  by  the  cracking  or  brc::king  off  of  the 
projection. 

For  light  buildings  of  only  one  or  two  stories,  used  for  dwellings 
or  similar  purposes,  irregular-shaped  stones,  called  "heavy  rubble," 
are  generally  used,  as  shown  in  Fig.  55,  which  represents  a  plan  of 
the  footing  course,  the  spaces  between  the  larger  stones  being 
filled  in  with  smaller  stones.    Each  stone  should  be  laid  in  cement 


go 


BUILDING  CONSTRUCTION.         (Ch.  Ill) 


mortar  and  the  spaces  between  the  stones  sohdly  filled  with  mortar 
and  broken  stone.  ^ 

Under  heavy  buildings  the  footing  stones  should  be  what  are 
called  ''dimension  stones" ;  that  is,  roughly  squared  to  certain 
dimensions.  Dimension  stones  for  footings  may  be  obtained  from 
4  to  8  feet  in  length,  according  to  the  kind  of  stone.  The  width  of 
the  stones,  measured  lengthwise  of  the  wall,  should  be  at  least  2 
feet,  or  two-thirds  the  wadth  of  the  footings. 

The  best  stones  for  heavy  footings  are :  Granite,  bluestone,  slate 
and  some  hard  laminated  sandstones  and  limestones. 

102.  BEDDING  OF  FOOTING  STONES.— As  footing  stones 
are  generally  very  rough,  being  left  as  they  come  from  the  quarry, 
they  cannot  be  made  to  bear  evenly  on  the  bottom  of  trenches  with- 
out being  bedded  either  in  a  thick  bed  of  mortar,  or,  if  the  soil 
is  sand  or  gravel,  by  washing  the  sand  into  the  spaces  by  means 
of  a  stream  of  water.  As  a  rule,  the  only  safe  way  is  to  specify 
that  the  stones  shall  be  set  in  a  thick  bed  of  cement  mortar  and 
worked  around  with  bars  until  they  are  solidly  bedded. 

103.  OFFSETS. — The  projection  of  the  footings  beyond  the 
wall,  or  the  cours'e  above,  is  a  point  that  must  be  carefully  con- 
sidered, whatever  be  the  material  of  the  footings. 

If  the  projection  of  the  footing  or  offset  of  the  courses  is  too 
great  for  the  strength  of  the  stone,  brick  or  concrete,  the  footing 
will  crack,  as  shown  in  Fig.  56. 

The  proper  offset  for  each  course  will  depend  upon  the  vertical 
pressure,  the  transverse  strength  of  the  material,  and  the  thickness 
of  the  course.    Each  footing  stone  may  be  considered  as  a  beam^ 

TABLE  VII. 

Safe  Offsets  for  Masonry  Footing  Courses. 


KIND  OF  FOOTING. 

R.  IN 
LBS.  PER 
SQ.  IN.* 

OFFSET  FOR  A  PRESSURE.  IN  TON 
FOOT  ON  THE  BOTTOM  OF  THE 

«.    PER  SQUARE 
COURSE,  OF 

0.5 

I 

2 

3 

5 

10 

2,700 

3-6 

2.6 

1.8 

1-5 

1.2 

.8 

1,800 

2.9 

2.x 

1-5 

Z.3 

I 

•y 

1,500 

27 

1.9 

1-3 

I.I 

.6 

1.200 

2.6 

1.8 

■^•3 

ID 

i 

•s 

Slate   

5,400 

5-0 

3-6 

2-5 

2.2 

z.a 

1,200 

2.6 

1.8 

»-3 

I.O 

.8 

•S 

150 

0.8 

0.6 

04 

80 

0.6 

0.4 

0.3 

*  Modulus  of  Rupture,  values  given  by  Ira  O.  Baker  in  "Treatise  on  Masonry  Construction.' 


MASONRY  FOOTINGS.  91 

fixed  at  one  end  and  uniformly  loaded,  and  in  this  way  the  safe 
projection  may  be  calculated. 

Table  VII  gives  the  safe  offset  for  masonry  footing  courses,  in 
terms  of  the  thickness  of  the  course,  computed  with  a  factor  of 
safety  of  10. 

It  should  be  borne  in  mind  that  as  each  footing  course  transmits 
the  entire  weight  of  the  wall  and  its  load,  the  pressure  will  be 
greater  per  square  foot  on  the  upper  courses,  and  the  offsets  should 
be  made  proportionately  less. 


Fig.    55.    Plan    of   Heavy   Rubble    Footing   Course.  Fig.     56.       Footing  Crack 

Caused  by  Too  Great 
Projection. 

104.  EXAMPLE  OF  STONE  FOOTING  COURSE  OFF- 
SETS.— A  4  feet  wide  footing  course  of  limestone  transmits  a  load 
of  12  tons  per  lineal  foot  or  3  tons  per  square  foot ;  the  thickness  of 
the  course  is  10  inches.  What  should  be  the  width  of  the  course 
above  ? 

Solution. — From  the  table  under  the  column  headed  3  we  find  the 
projection  to  be  i.i  times  the  thickness,  or  in  this  case  11  inches. 
As  we  would  have  the  same  projection  each  side  of  the  wall,  the 
stone  above  may  be  22  inches  less  in  width,  or  2  feet  2  inches  wide. 
Except  in  cases  where  it  is  necessary  to  obtain  very  wide  footings 
it  is  better  not  to  make  the  offsets  more  than  6  or  8  inches,  and  in 
the  case  above  it  would  be  better  to  make  the  upper  footing  course 
3  feet  wide.  Most  building  ordinances  require  the  projection  of 
the  footings  beyond  the  foundation  wall  to  be  at  least  6  inches  on 
each  side. 

105.  BRICK  FOOTINGS. — On  sandy  soils  brick  foundations 
and  footings  may  be  used  when  good  stone  cannot  be  cheaply 
obtained.  In  Denver,  Col.,  where  the  soil  is  a  mixture  of  sand  and 
clay,  very  dry  and  unaffected  by  frost,  brick  foundations  have  been 
found  to  answer  the  purpose  fully  as  well  as  stone  for  two  and 
three-story  buildings. 

In  building  brick  footings,  the  principal  point  to  be  attended  to 
is  to  keep  the  back  joints  as  far  as  possible  from  the  face  of  th-s 


92 


BUILDING  CONSTRUCTION.  (Ch.  Ill) 


work;  and  in  ordinary  cases  the  best  plan  is  to  lay  the  footings  in 
single  courses,  the  outside  of  the  work  being  laid  all  headers,  and 
no  course  projecting  more  than  one-quarter  brick  beyond  the  one 
above  it,  except  in  the  case  of  unloaded  9-inch  walls.  The  bottom 
course  should  in  all  j^ases  be  a  double  one.  Figs.  57  to  60  show  the 
proper  arrangement  of  the  brick  in  walls  from  one  to  three  bricks 
in  thickness.    If  the  ground  is  soft  and  compressible,  or  the  wall 


Fig.  57- 


«^-2-bks--? 


HI 


1  r 


Fig.  58. 


< — -  3  bks:  ^ 


1  r 


I  ,1  I,  r. 


I  r 


Fig.  59.  Fig.  60. 

Figs.    57-60.    Examples    of    Brick    Footings.    Proper    Arrangement    of  Bricks. 


heavily  loaded,  the  footings  should  be  made  wider,  as  shown  in 
Fig.  61.  For  brick  footings  under  high  walls,  or  walls  that  are 
very  heavily  loaded,  each  projecting  course  should  be  made  double, 
the  heading  course  above  and  the  stretching  course  below. 

The  bricks  used  for  footings  should  be  the  hardest  and  soundest 
that  can  be  obtained,  and  should  be  laid  in  cement  or  hydraulic  lime 
mortar,  either  grouted  or  thoroughly  slushed  up,  so  that  every 

joint  will  be  entirely  filled  with  mor- 
tar. The  writer  favors  grouting  for 
brick  walls ;  that  is,  using  thin  mortar 
for  filling  the  inside  joints,  as  he  has 
always  found  that  it  gives  very  sat- 
isfactory  results. 

I    I   *    I    ^    I    *    I    '  The  bottom  course  of  the  footing 

should  always  be  laid  in  a  bed  of 
mortar  spread  on  the  bottom  of  the 


1 — n 


ick  Footings  for 


Fig.   61.    Wide  Br 

Heavy  Walls  on  CompresS' 
ible  Soils. 


MASONRY  FOOTINGS,  93 

trench,  after  the  latter  has  been  carefully  levelled.  All  bricks  laid 
in  warm  or  dry  weather  should  be  thoroughly  wet  before  laying, 
for,  if  laid  dry,  they  rob  the  mortar  of  a  large  percentage  of  its 
moisture,  greatly  weakening  its  adhesion  and  strength. 

106.  IMPORTANCE  OF  CAREFUL  CONSTRUCTION  OF 
FOOTING  COURSES. — Too  much  care  cannot  be  bestowed  upon 
the  footing  courses  of  any  building,  as  upon  them  depends  much  of 
the  stability  of  the  work.  If  the  bottom  courses  are  not  solidly  bedded, 
if  any  seams  or  vacuities  are  left  in  the  beds  of  masonry,  or  if  the 
materials  themselves  are  unsound,  the  effects  of  such  carelessness 
are  sure  to  show  themselves  sooner  or  later,  and  almost  always 
when  they  cannot  be  well  remedied.  Nothing  is  more  apt  to  injure 
the  reputation  of  a  young  architect  than  to  have  a  building  con- 
structed under  his  direction  settle  and  crack ;  and  he  should  see  per- 
sonally that  no  part  of  the  foundation  work  is  in  any  way  slighted. 

107.  STEPPED  BRICK  FOOTINGS  ON  CONCRETE 
FOUNDATION. — In  the  construction  of  footings  under  brick 
walls  a  bed  of  concrete  is  commonly  used,  and  the  brickwork  off- 
setted  from  this  bed  up  to  the  required  thickness  for  the  wall.  Such 
stepped-up  brick  footings,  with  concrete  beds  or  footings  beneath, 
are  shown  in  Fig.  62  at  (a)  and  {h) .    The  illustration  represents 

the  vertical  cross-section  of 
an  exterior  wall  of  a  building 
built  close  to  the  street  or 
party-line.  In  the  figure,  at 
(a),  the  footing  is  formed  by 
stepping  back  each  course  of 
brickwork,  while  at  (b)  the 
stepping  is  made  at  every 
other  course.  Either  of  these 
methods  of  building  brick 
footings,  with  the  projections 
given  in  the  illustration,  meets 
the  requirements  of  the  New 
York  building  law. 

108.  INVERTED  ARCHES. — Inverted  arches  are  sometimes 
built  under  and  between  the  bases  of  piers,  as  shown  in  Fig.  63,  with 
the  idea  of  distributing  the  weight  of  the  piers  over  the  whole  length 
of  the  footings.  This  method  is  objectionable,  first,  because  it  is 
nearly  impossible  to  prevent  the  end  piers  of  a  series  from  being 


94 


BUILDING  CONSTRUCTION.         (Ch.  Ill) 


Illustration  of  Inverted  Arches. 


pushed  outward  by  the 
thrust  of  the  arch,  as 
shown  by  the  dotted 
line ;  and  secondly,  be- 
cause it  is  generally  im- 
possible with  inverted 
arches  to  make  the  areas 
of  the  different  parts  of 
the  foundation  propor- 
tional to  the  load  to  be 
supported.  It  is  much 
better  to  build  the  piers 
with  separate  footings,  projecting  equally  on  all  four  sides  and 
proportioned  to  the  loads  they  support.  The  intermediate  walls 
may  be  supported  by  steel  beams  or  arches,  as  preferred. 

In  some  instances,  however,  when  building  on  comparatively  soft 
soils,  and  where  it  is  impracticable  to  use  spread  footings,  inverted 
arches  may  be  advantageously  used,  especially  when  it  is  necessary 
to  reduce  the  height  of  the  footing  to  a  minimum. 

If  it  is  decided  to  use  inverted  arches,  the  foundation  bed  should 
be  levelled  and  a  footing  built  over  the  whole  bed  to  a  depth  of  at 
least  from  12  to  18  inches  below  the  bottom  of  the  arch.  Concrete  is 
much  the  best  material  for  this  footing,  although  brick  or  stone  may 
be  used  if  found  more  economical.  The  uppe;:  surface  of  the  foot- 
ing should  be  accurately  formed  to  receive  the  arch,  which  should  be 
built  of  hard  bricks  laid  in  cement  mortar,  generally  in  separate 
rings  or  rowlocks,  and  should  abut  against  stone  or  concrete  skew- 
backs,  as  shown  in  Fig.  64. 

It  is  better  to  build  the  arches  before  putting  in  the  skewbacks, 
and  for  the  latter  i  to  6  Portland  cement  concrete  possesses  special 


Fig.  64.    Details  of  Footings  with  Inverted  Arches. 


MASOXRV  FOOTIXGS. 


95 


advantages,  as  it  can  be  deposited  between  the  ends  of  the  arches 
and  rammed  evenly  and  simuhaneously,  giving  a  sohd  and  uniform 
bearing  against  the  ends  of  the  arches,  and  tending  to  prevent 
unequal  settlement  and  cracking. 

109.  Above  the  concrete  skewback  a  solid  block  of  stone  should 
be  placed  if  it  can  be  readily  obtained.  The  thickness  of  the  arcli 
ring  should  be  at  least  12  inches,  and  heavy  iron  plates  or  washers 
should  be  set  in  the  middle  of  the  concrete  skewbacks  and  connected 
with  iron  or  steel  rods,  to  take  up  the  thrust  of  the  end  arches.  The 
"rise"  of  the  arch,  or  distance  R,  Fig.  64,  should  be  equal  to  from 
to  X)  tlie  span.  The  sectional  area  of  the  arch  should 
equal  the  result  obtained  by  the  following  formula: 

Section  of  arch  in  sq.  ins.  ^Total  load  on  arch_(in  lbs.)  X  span 

8X^X10 

For  wrought-iron  tie-rods 

o  -      ,   .         .         Total  load  on  arch  (in  lbs.)X  span 

Section  ot  rods  m  sq.  ms.  =  q  , ,  p  v .  o  —  (8) 

8  X     X  850  ^  ^ 

For  steel  tie-rods 

.       ,      .    .         .         Total  load  on  arch  X  span  ,  ^ 

Section  of  rods  m  sq.  ins.  =  ^  — —  (q\ 

^  SX  RX  1050 

the  span  being  measured  in  feet,  and  the  distance  R  in  inches. 

The  load  on  the  arch  will  be  equal  to  the  span  multiplied  by  the 
pressure  per  lineal  foot  imposed  on  the  soil.  The  latter  will  be 
obtained  by  dividing  the  load  on  the  piers  by  the  distance  betweert 
centers  of  piers. 

no.  EXAMPLE  IN  CALCULATION  FOR  INVERTED 
ARCH  FOOTINGS. — It  is  desired  to  use  inverted  arches  between 
the  piers  of  a  three-story  building,  resting  on  a  soil  whose  bearing 
power  cannot  be  safely  estimated  at  over  3,000  pounds  per  square 
foot.  The  piers  are  of  stone,  4  feet  long,  22  inches  thick,  and  14 
feet  apart  on  centers.  Each  pier  supports  a  total  load  of  98,00a 
pounds.  What  should  be  the  sectional  area  of  the  arch,  and  of  the 
rods  in  the  end  spans? 

Solution. — The  span  of  the  arch  will  be  10  feet,  and  the  distance 
R  about  one-fifth  of  10  feet,  or  24  inches.  The  load  per  lineal  foot 
on  the  soil  will  equal  98,000^14,  or  7,000  pounds.  The  footings 
under  the  arch  must  therefore  be  2  feet  4  inches  wide  to  reduce  the 
pressure  to  3,000  pounds  per  square  foot.    The  width  of  the  arch 


96 


BUILDING  CONSTRUCTION,  (Ch.  Ill) 


itself  we  will  make  22  inches,  or  two  and  one-half  bricks.    The  tolal 
load  on  the  arch  will  equal  10X7,000,  or  70,000  pounds. 
The  sectional  area  of  the  arch  must  therefore  equal 

70000  X  10  .  , 

5-—  — —  or  354  square  niches. 

8  X  24  X  10  ^ 

As  the  width  is  22  inches,  the  depth  must  equal  354-^-22,  or  16 
inches,  which  will  require  four  rowlocks  or  rings. 

The  sectional  area  of  the  ties  must  equal,  for  wrought-iron, 

70000  X  10  .  , 

■^r— — — T-Ts —  or  4-3  square  mches. 
8  X  24  X  850      ^  ^  ^ 

In  this  case  it  will  be  better  to  use  two  rods  of  2.15  square  inches  in 
area,  or  two  i^-inch  rods. 

All  cast-iron  work  in  the  foundation  should  be  coated  with  hot 
asphalt,  and  the  rods  should  be  dipped  in  linseed  oil  while  new  and 
hot  and  afterward  painted  one  heavy  coat  of  oxide  of  iron  or  red 
lead  paint. 

2.    FOUNDATION  WALLS 

111.  GENERAL  DESCRIPTION.— This  term  is  generally 
applied  to  those  walls  which  are  below  the  surface  of  the  ground, 
and  which  support  the  superstructure.  Walls  whose  chief  office  is 
to  withhold  a  bank  of  earth,  like  those  around  areas,  are  called 
retaining-walls. 

Foundation  walls  may  be  built  of  stone,  brick  or  concrete,  the 
first  being  the  most  common.  Brick  walls  for  foundations  are 
only  suitable  in  very  dry  soils,  or  in  the  case  of  party-walls,  where 
there  is  a  cellar  or  basement  each  side  of  them. 

As  the  method  of  building  brick  foundations  is  the  same  as  for 
any  brick  wall,  it  will  not  be  described  here,  but  will  be  taken  up  in 
the  chapter  on  Brickwork.    For  concrete  walls  see  Chapter  X. 

112.  STONE  WALLS. — The  principal  details  to  be  watched 
in  building  a  stone  foundations  wall  are  the  character  of  the  stone 
and  mortar,  and  the  bonding,  filling  of  voids  and  pointing. 

The  best  stones  for  foundations  are  granites,  compact  sand- 
stones, slates  and  blue  shale.  The  less  porous  the  stone  the  better 
it  will  stand  the  dampness  to  which  it  must  be  subjected.  As  a 
rule  laminated  stones  make  the  best  walls,  as  they  split  easily  and 
give  flat  and  parallel  beds.   If  the  only  stones  to  be  had  are  boulders 


FOUNDATION  WALLS. 


97 


or  field-stones,  they  should  be  split  so  as  to  form  good  bed-joints. 
Cobble  or  round  stones  should  never  be  used  for  building  founda- 
tion walls,  and  for  all  buildings  exceeding  three  stories  in  height, 
block  stone  or  the  best  qualities  of  laminated  stone  should  be  used. 

The  mortar  for  foundation  walls  below  the  grade  line  should  be 
made  either  of  Portland  cement,  natural  cement,  or  hydraulic  lime, 
with  coarse  sand ;  while  above  grade  good  common  lime,  or  lime 
and  cement,  may  be  used.  . 

The  usual  practice  in  building  foundations  is  to  use  the  stone 
just  as  it  is  blasted  from  the  quarry;  or,  if  the  building  is  built  on 
a  ledge,  the  material  from  the  foundation  itself,  the  stone  receiving 
no  preparation  other  than  a  breaking  up  with  a  sledge-hammer,  and 
the  squaring  of  one  edge  for  the  face.  Too  great  irregularity  and 
unevenness  is  overcome  by  sparing  the  use  of  the  stone-hammer  and 
by  varying  the  thickness  of  the  mortar  joint  in  which  the  stones  are 
bedded.  The  strength  of  the  wall,  therefore,  depends  largely  upon 
the  quality  of  the  mortar  used. 

The  wall  should  be  levelled  off  about  every  2  feet,  so  as  to  form 
irregular  courses,  and  the  horizontal  joints  should  be  kept  as  nearly 
level  as  possible. 

When  block  stones  are  used  they  are  generally  from  18  inches 
to  2  feet  thick  and  the  full  width  of  the  wall.  They  are  commonly 
roughly  squared  with  the  hammer,  and  but  little  mortar  is  used  in 
the  wall.  Only  in  a  few  localities,  however,  are  such  stones  obtain- 
able at  a  price  that  will  permit  of  their  use,  so  that  as  a  rule  stones 
split  from  a  ledge  and  called  ''rubble"  are  the  materials  with  which 
the  architect  will  have  to  deal. 

113.  BONDING. — Aside  from  the  quality  of  the  stone  and 
mortar,  the  strength  of  a  rubble  wall  depends  upon  the  manner  in 
which  it  is  bonded  or  tied  together  by  lapping  the  stones  over  each 
other.  About  every  4  or  5  feet  in  each  course  a  bond-stone  should 
be  used ;  that  is,  a  stone  that  will  go  entirely  through  the  wall,  and, 
by  its  friction  on  the  stones  below,  hold  them  in  place.  A  stone 
that  goes  three-fourths  of  the  way  through  the  wall  is  called  a 
three-quarter  bond.  It  is  customary  to  specify  that  there  shali- 
be  at  least  one  through-stone  in  every  5  or  10  square  feet  of 
the  wall,  depending  upon  the  character  of  the  stone  and  nature  of 
the  building.  Fig.  65  shows  a  portion  of  wall  built  of  square  or 
laminated  stones,  with  through  bond-stones  at  B  B,  and  three-quarter 


FOUNDATION  WALLS. 


99 


bond-stones  2ii  A  A.  A  good  three-quarter  bond  is  nearly  equal  in 
strength  to  a  through-bond,  and  when  the  character  of  the  stone 
will  permit  of  the  wall  being  built  largely  of  flat  stones  extending 
two-thirds  of  the  way  through  the  wall,  it  will  not  be  necessary  to 
use  more  than  one  through-stone  to  every  lo  square  feet  of  wall. 
No  stone  should  be  built  into  the  face  of  a  wall  with  a  depth  less 
than  6  inches,  although  stone-masons  will  often  set  a  stone  on 
edge,  so  as  to  make  a  good  face  and  to  give  the  appearance  of  a 
large  stone,  when  it  may  be  only  3  inches  thick.  All  kinds  of  stones 
should  always  be  laid  so  that  their  natural  bed,  or  splitting  surface, 
will  be  horizontal.  It  is  also  important  that  the  stones  shall  break 
joint  longitudinally,  as  in  Fig.  65,  and  not  have  several  vertical 
joints  over  each  other,  as  at  A  A,  Fig.  66.  The  angles  of  the  foun- 
dation should  be  built  up  of  long  stones,  laid  alternately  header  and 
stretcher,  as  shown  in  Fig.  67  The  largest  and  best  stones  should 
always  be  put  in  the  corners,  as  these  are  usually  the  weakest  parts 
of  a  wall. 

114.  FILLING  VOIDS.— All  stones,  large  and  small,  should 
be  solidly  bedded  in  mortar,  and  all  chinks  or  interstices  between 
the  large  stones  should  be  partially  filled  with  mortar  and  then 
with  small  pieces  of  stone,  or  spalls,  driven  into  the  mortar  with 
the  trowel,  and  then  smoothed  off  on  top  with  mortar. 

Many  masons  are  apt  to  build  the  two  faces  of  a  wall  with 
long,  narrow  stones  and  fill  in  between  with  dry  stones,  throwing 
a  little  mortar  on  top  to  make  it  look  well. 

A  horizontal  section 
through  such  a  wall  would 
appear  as  shown  in  Fig. 
68.  A  wall  of  this  kind 
would  require  but  little 
loading  to  cause  the  out- 
side faces  to  bulge,  owing 
to  the  lack  of  strength  in 
its  middle  portion.  The 
way  in  which  a  wall  of 
irregularly  shaped  stones 
should  be  built  in  order  to 
be  as  strong  as  possible  is  shown  in  Fig.  69. 

A  wall  of  this  kind  requires  no  more  stone  than  the  other,  but 
requires  more  lifting  and  a  little  more  work  with  the  hammer,  and 


Fig.    68.     Section   of  Poorly   Built   Rubble  Stone 
Wall. 


Fig.  69.     Section  of  Properly  Built  Rubble  Stone 
Wall. 


TOO  BUILDING  CONSTRUCTION.         (Ch.  Ill) 


these  appear  to  be  the  real  reasons  why  better  workmanship  does 
not  oftener  result. 

115.  WINDOW  OPENINGS.— If  there  should  be  a  window 
or  door  opening  in  the  foundation  w^all,  as  in  Fig.  70,  the  stones 
just  below  the  opening  should  be  laid  so  as  to  spread  the  weight 


Fig.  70.    Stones  Under   Window  Opening.    Proper  Method. 


of  the  wall  under  it,  as  shown  by  the  stones  A  B  C.  If  any  great 
weight  is  to  come  upon  the  foundation  it  is  better  not  to  build  the 
windov/  sills  into  the  wall,  but  to  make  their  length  just  equal  to  the 
width  of  the  opening.  These  are  called  ''slip-sills,"  and  there  is  no 
danger  of  their  breaking  by  uneven  settlement. 

Occasionally  some  part  of  the  foundation  wall  of  a  building  goes 
down  much  lower  than  the  adjoining  portions,  and,  as  there  is 
almost  always  a  slight  settlement  in  the  joints  of  a  wall,  unless 
laid  in  cement  the  deeper  wall  will  naturally  settle  more  than  the 
other,  and  thus  cause  a  slight  crack.  This  can  be  avoided  by 
building  the  deeper  wall  of  larger  stones,  so  that  there  will  be  no 
more  joints  than  in  the  other  wall,  or  by  making  thin  joints  and 
using  cement  mortar. 

116.  THICKNESS  OF  FOUNDATION  WALLS.— The 
thickness  of  a  foundation  wall  is  usually  governed  by  that  of  the 
wall  above,  and  also  by  its  own  depth. 

Nearly  all  building  regulations  require  that  the  thickness  of  a 
foundation  wall,  to  a  depth  of  12  feet  below  the  grade  line,  shall 
be  4  inches  greater  than  the  wall  above  for  brick  and  8  inches 


RETAIXIXG-WALLS. 


lor 


greater  for  stone ;  and  that  for  every  additional  lo  feet,  or  part 
thereof  in  depth,  the  thickness  shall  be  increased  4  inches.  In  all 
large  cities  the  thickness  o'f  the  walls  is  controlled  b}^  law.  In  cases 
where  the  thickness  is  not  so  governed  the  following  table  will  serve 
as  a  fair  guide : 

TABLE  VIII. 
Proper  Thickness  for  FoundatiOxN  Wall.s. 


HEIGHT  OF  BUILDING. 

DWELLINGS,  HOTELS, 
ETC. 

WAREHOUSES. 

BRICK. 

STONE. 

BRICK. 

STONE. 

Ins. 

Ins. 

Ins. 

Ins. 

12  or  16 

20 

16 

20 

16 

20 

20 

24 

20 

24 

24 

28 

24 

28 

24 

28 

24 

28 

28 

32 

Only  block  stone,  or  first-class  rubble,  with  flat  beds,  should  be 
used  in  foundations  for  buildings  exceeding  three  stories  in  height. 
The  footings  should  be  at  least  12  inches  wider  than  the  width  of 
the  walls.    (See  Article  98.) 

In  heavy  clay  soils  it  is  a  good  idea  to  batter  the  walls  on  the 
outside,  making  the  wall  from  6  inches  to  a  foot  thicker  at  the 
bottom  than  it  is  at  the  top,  and  plastering  the  outside  with  cement. 
(See  Fig.  6,  Article  10.) 

3.  RETAINING-WALLS 

117.  GENERAL  DESCRIPTION.— A  retaining-wall  is  one 
that  is  built  to  hold  up  a  bank  of  earth,  which  is  deposited  behind 
it  after  it  is  built.  The  term  hreast-zvall  or  face-wall  is  used  for  a 
similar  structure  built  to  prevent  the  fall  of  earth  which  is  in  its 
undisturbed  natural  position,  but  in  which  a  vertical  or  inclined  face 
has  been  left  after  the  excavations.  Retaining-walls  also  differ  from 
foundation  walls,  in  that  the  latter  support  superstructures  whose 
weights  are  generally  sufficient  to  overcome  the  thrust  of  the  earth 
against  the  walls.  Retaining-walls  depend  upon  their  own  stability 
to  resist  earth-pressure. 

Area  walls  generally  serve  as  retaining-walls,  but  as  they  are 
usually  braced  by  arches  or  cross  walls  from  the  building  wall, 
they  do  not  require  the  same  thickness.as  a  jetaining-wall  proper. 


102 


BUILDING  CONSTRUCTION.         (Ch.  Ill) 


Cham^'in^  Jireef' 
Grade 


Buu 


I 


oj'  the  Ecirfh  Backing 


ig.  71.    Retaining- Wall  and  Foundation  Wall.    Poor  Construction. 


Several  theoretical  formulas  have  been  proposed  by  writers  on 
engineering  subjects  for  computing  the  necessary  thickness  and 
most  economical  section  for  retaining-walls ;  but  so  many  varying 
conditions  enter  into  the  designing  of  such  walls,  such  as  the  char- 
acter and  cohesion  of  the  soil,  the  extent  to  which  the  bank  has  been 
disturbed,  the  manner  in  which  the  material  is  filled  in  against  the 
wall,  etc.,  that  little  confidence  is  placed  in  these  theoretical  formulas, 
and  engineers  appear  to  be  guided  rather  by  empirical  rules. 

118.  MANNER  OF  FAILURE.— Retaining-walls  may  fail  in 
any  one  of  several  ways;  by  tipping  or  overturning;  by  bulging; 
or  by  the  sliding  of  the  footings.  The  first  is  the  most  common 
form  of  failure  and  is  caused  by  the  pressure  of  the  earth  backing, 
overturning  the  wall  about  the  outside  edge  of  the  footing  or  wall. 
A  retaining-wall  may  fail  also  by  bulging,  caused  by  filling  in  back 
of  the  wall  while  the  masonry  is  still  green ;  by  water  penetrating 
back  of  the  wall  and  freezing;  or  by  a  change  in  the  nature  of  the 
soil  due  to  heavy  rains.  While  the  failure  of  a  retaining-wall  by 
the  sliding  of  the  footings  is  not  frequent,  it  has  sometimes  occurred 
where  it  has  been  sufficiently  heavy  to  resist  overturning,  and  where 
the  footings  have  been  built  on  unstable  soil,  such  as  slippery  clay, 
or  other  unctuous  material. 

Ret^jning-walls  which  .hpld  „back  ea,rth  embankments  liable  to 


RETAIN  IN  G-W  ALLS.  103 

vibration  from  passing  trains  or  from  heavy  street  traffic  are  more 
likely  to  fail  than  walls  not  subjected  to  such  vibration,  and  should 
be  made  from  25  per  cent  to  50  per  cent  heavier.  The  foundation 
walls  and  area  walls  of  buildings  are  frequently  required  to  act 
as  retaining-walls  along  railroad  sidings  and  should  be  carefully 
designed  to  meet  this  condition. 

The  failure  of  a  retaining-wall  has  been  caused  by  the  over- 
loading of  the  earth  embankment  or  the  backing  which  it  supports. 
A  condition  likely  to  cause  failure  is  shown  in  Fig.  71,  where  the 
footing  of  an  adjacent  building  is  not  down  to  the  level  of  the 
footing  of  the  retaining-wall  required  by  the  changing  of  the  grade 
of  the  street. 

119.  DESIGN  AND  CONSTRUCTION.— The  cross-section 
that  appears  to  be  generally  approved  for  retaining-walls,  particu- 
larly in  engineering  work,  is  shown  in  Fig.  72. 

The  wall  may  be  either  built 
plumb,  a-s  shown,  or  inclined 
toward  the  bank.  The  latter 
method  is  generally  considered 
to  result  in  greater  stability, 
although  it  is  open  to  the  objec- 
tion that  the  water  which  runs 
down  the  face  of  the  wall  is  apt 
to  penetrate  into  the  inclined 
joints. 

Retaining-walls  should  be 
built  only  of  good  hard  split  or 
block  stone,*  laid  in  cement 
mortar  and  carefully  bonded,  to 
prevent  the  stones  from  sliding 
on  the  bed- joints. 

Fig.     72.    Rctaining-Wall.    Generally    Ap-  The   thickuCSS    of   the    Wall  at 

proved  Section. 

the  top  should  be  not  less  than 
18  inches,  and  the  thickness,  a,  just  above  each  step  should  be  from 
Yz      Ys  oi  the  height  from  the  top  of  the  wall  to  -that  point. 

If  the  earth  is  banked  above  the  top  of  the  wall,  as  shown  by 
the  dotted  line,  Fig.  72,  the  thickness  of  the  wall  should  be  in- 
creased.   A  thickness  equal  to  one-half  of  the  height  will  generally 


-  CL- — ; 


*  Or  of  Portland  cement  concrete  with  metal  reinforcements. 


I04 


BUILDING  CONSTRUCTION. 


(Ch.  Ill) 


answer  for  a  height  of  embankment  equal  to  one-third  the  height 
of  the  wall. 

The  outer  face  of  the  wall  is  generally  battered,  or  sloped  out- 
ward, about  I  inch  to  the  foot, 

Stepping  the  wall  on  the  back  increases  the  stability  by  bonding 
it  into  the  material  behind  and  by  increasing  the  weight  by  the 
weight  of  the  soil  resting  upon  the  steps. 

Care  should  be  used  in  filling  in  back  of  a  retaining-wall,  for  the 
stability  varies  considerably  with  the  method  employed.  The  sta- 
bility of  the  wall  is  increased  if  the  earth  is  well  rammed  in  layers 
inclined  down  from  the  wall,  whereas  if  the  earth  is  filled  in  in 
layers  sloping  up  toward  the  wall,  it  must  be  made  stronger  to  resist 
the  full  pressure  of  the  earth. 

If  built  upon  ground  that  is  affected  by  frost  or  surface  water, 
the  footings  should  be  carried  sufficiently  below  the  surface  of  the 
ground  at  the  base  of  the  wall  to  insure  against  heaving  or  settling. 

If  the  ground  back  of  the  wall  slopes  toward  the  wall  a  cement 
gutter  should  be  formed  behind  the  coping  and  connected  with  a 
drain  pipe  to  carry  off  the  surface  water.  The  back  of  the  wall  and 
the  tops  of  the  steps  should  be  plastered  with  cement  to  the  depth 
of  at  least  3  or  4  feet. 

120.    REINFORCED  CONCRETE  RETAINING-WALLS.— 

Retaining-walls  are  now  fre- 
quently constructed  of  rein- 
forced concrete,  and  are  built 
as  shown  in  the  section  in 
73-  Such  walls  depend 
for  their  stability  rather  upon 
the  wide  reinforced  concrete 
base  than  upon  the  dead 
weight  of  the  concrete.  As  a 
rule,  reinforced  concrete  re- 
taining-walls are  not  more 
than  8  inches  in  thickness  at 
the  top  and  18  inches  at  the 
bottom.  The  concrete  of  the 
retaining-wall  is  reinforced  so 
as  to  resist  the  pressure  of  the 
earth  backing,  by  providing 
sufficient  transverse  strength 


AREA  iVALLS. 


or  resistance  to  bending  between  the  wall  and  the  footing ;  and  the 
width  of  the  footing,  together  with  the  weight  of  the  earth  backing 
upon  it,  adds  additional  stability  to  the  wall.  The  footing  is  also 
reinforced  sufficiently  to  prevent  its  failing  by  transverse  or  bending 
stresses.  In  addition  to  the  reinforcing  rods,  the  wall  is  usually  pro- 
vided with  shrinkage  rods  running  horizontally  and  placed  about  2 
feet  on  centers.  They  are  made  of  from  yj-inch  to  J/^-inch  round  or 
square  bars.  The  concrete  used  in  such  w'alls  is  generally  made  of 
a  I,  and  5  mixture  of  cement,  sand  or  gravel,  and  broken  stone 
respectively.  The  exposed  face  of  the  wall  is  molded  smooth  by 
the  use  of  planed  boards,  neatly  matched  in  the  construction  of  the 
forms ;  and  is  afterwards  washed  down  with  a  cement  wash  put  on 
with  a  soft  brush,  or  is  rubbed  with  carborundum  blocks  dipped  in 
a  cement  paint  or  wash. 

4.    AREA  WALLS 

121.  GENERAL  DESCRIPTION.— Areas  are  often  exca- 
vated outside  the  foundation  w^alls  of  buildings  to  give  light  or 
access  to  the  basement,  and  require  surrounding  walls  to  retain 
the  earth  and  present  a  neat  appearance. 

Such  walls  should  be  built  of  stone,  as  stone  walls  offer  greater 
resistance,  when  the  mortar  is  green,  to  sliding  on  the  bed- joints 
than  is  offered  by  brick  walls. 

In  making  the  excavation  the  earth  should  be  disturbed  as  little  as 
possible,  and  in  filling  against  the  walls  the  soil  should  be  deposited 
in  layers  and  well  tamped,  and  not  dumped  in  carelessly.  Either 
the  filling  should  be  delayed  until  the  mortar  has  had  time  to  harden, 
or  the  walls  should  be  well  braced. 

Area  w^alls  are  commonly  built  like  foundation  walls  with  a 
uniform  thickness  of  about  20  inches  for  a  depth  of  7  feet.  If 
more  than  7  feet  in  height  the  walls 
should  have  a  batter  on  the  area  side 
and  should  be  increased  in  thickness  at 
the  bottom,  so  that  the  average  thickness 
will  be  at  least  one-third  of  the  height, 
unless  the  walls  are  braced  by  arches, 
buttresses  or  cross  walls. 

Area  walls  sustaining  a  street  or  alley 
should  be  made  thicker  than  those  in  an 
open  lot. 


Fig.  74.  Area  Wall  P.racLHl  by 
Arch. 


io6       •  BUILDING  CONSTRUCTION.         (Ch.  Ill) 


When  an  area  wall  is  more  than  lo  feet  long  it  is  generally  prac- 
ticable to  brace  it  from  the  basement  wall  by  arches  thrown  across 
from  one  wall  to  the  other,  as  shown  in  Fig.  74.  When  this  cannot 
be  done  the  wall  should  be  stiffened  by  buttresses  about  every 
10  feet. 

5.    VAULT  WALLS 

122.  GENERAL  DESCRIPTION.— In  large  cities  it  is  cus- 
tomary to  utilize  the  space  under  the  sidewalk  for  storage  or  other 
purposes.  This  necessitates  a  wall  at  the  curb  line  to  sustain  the 
street  and  also  the  weight  of  the  sidewalk. 

Where  practicable,  the  space  should  be  divided  by  partition  walls 
about  every  10  feet,  and  when  this  is  done  the  outer  wall  may  be 
advantageously  built  of  hard  bricks  in  he  form  of  arches,  as  shown 
in  Fig.  75. 

The  thickness  of  the  arches  should  be  at  least  16  inches  for  a 
depth  of  9  feet,  and  the  ''rise"  of  the  arch  }^  of  the  span. 

If  partitions  are  not  practicable,  each  sidewalk  beam  may  be 
supported  by  a  heavy  I-beam  column,  with  either  flat  or  segmental 
arches  between,  as  shown  in  Fig.  76^ 

This  latter  method  is  more  economical  of  space  than  any  other, 
and  where  steel  is  cheap  is  about  as  economical  in  cost. 


Fig.    75.    Arched    Sidewalk    \'ault    Walls      Fig.    76.    Sidewalk    Vault    Walls    with  I- 
with  Partition  Walls.  Beam   Columns   and   Flat  Arches. 


6.    SUPERINTENDENCE  OF  FOUNDATION  WORK. 

123.  THE  FOOTINGS  IN  GENERAL.— The  first  work  on 
the  foundations  is  the  placing  of  the  footings. 

If  they  are  of  concrete,  an  inspector  should  remain  on  the  work 
during  the  working  hours  to  see  that  every  batch  of  concrete  is 
mixed  exactly  as  specified,  that  the  aggregates  are  broken  to  the 


FOOTING  DETAILS. 


107 


proper  size  and  that  the  cement  is  all  of  the  same  brand  and  in 
good  condition.  There  is  no  building  operation  that  can  be  more 
easily  "skimped"  without  detection  than  the  making  of  concrete, 
and  the  only  way  in  which  the  architect  can  be  sure  that  his 
specifications  have  been  strictly  followed  is  by  keeping  a  reliable 
representative  constantly  on  the  ground.  The  inspector  should  see 
also  that  the  concrete  is  put  in  to  the  full  thickness  shown  on  the 
drawings,  and  that  it  is  levelled  and  tamped  every  6  inches  in  depth. 

When  water  is  encountered  in  the  trenches,  it  should  be  col- 
lected in  a  shallow  hole  and  removed  by  a  pump  or  drain,  as  ex- 
plained in  Article  35.  Very  often,  when  the  foundation  rests  on  the 
top  of  a  ledge,  underlying  gravel  or  clay,  running  water  will  be 
encountered  in  the  trenches  in  too  great  a  volume  to  be  readily 
removed.  In  this  case,  the  flow  of  water  should  be  intercepted  by 
a  drain  and  cesspool,  and  a  tight  drain  carried  from  the  latter  to  a 
sewer  or  to  a  dry  well  below  the  foundation  of  the  building. 

Concrete  footings  for  piers  not  more  than  4  or  5  feet  square  may 
be  built,  where  there  is  running  water,  by  making  large  bags  of  oiled 
cotton,  sinking  them  in  the  pit  and  filling  the  concrete  into  them 
immediately.  The  water  will  probably  rise  around  the  bags,  but  if 
the  latter  keep  the  water  away  from  the  concrete  until  the  cement 
has  had  time  to  set,  they  will  have  answered  their  purpose.  Water 
does  not  injure  concrete,  nor  mortar  made  of  cement,  after  they  have 
begun  to  harden ;  but  if  freshly-mixed  concrete  is  thrown  into  water, 
the  latter  separates  the  cement  from  the  sand  and  aggregates,  the 
cement  mixing  with  the  water  and  floating  away,  while  the  sand 
and  stone  drop  to  the  bottom.  For  this  reason  concrete  should 
never  be  thrown  into  trenches  containing  water. 

124.  DETAILS  OF  FOOTINGS,  WALLS,  MATERIALS, 
ETC. — If  the  footings  are  of  stone  the  presence  of  water  does  not 
do  as  much  harm,  provided  it  can  be  drained  so  as  not  to  attain 
a  greater  depth  than  3  or  4  inches.  Sometimes  the  bottom  of  a 
wall  is  used  as  a  drain  for  collecting  the  seepage  water,  and  the 
trench  is  partially  filled  with  stones  laid  without  rriortar,  as  explained 
in  Article  10. 

For  heavy  buildings,  however,  the  footings  should  be  solidly 
bedded  in  cement  mortar  when  the  trenches  are  reasonably  dry ; 
and  when  this  it  not  the  case,  in  sand  or  fine  gravel.  An  irregular 
footing  stone  can  often  be  bedded  more  solidly  by  piling  fine  sand 
around  it  and  then  washing  the  sand  under  the  stone  with  water. 


io8 


BUILBING  CONSTRUCTION. 


(Ch.  Ill) 


than  it  can  by  laying  it  in  cement  mortar.  The  former  method, 
however,  takes  more  time,  and  is  seldom  employed  when  mortar  can 
be  used  with  as  good  results. 

As  stated  in  Article  105,  too  much  care  cannot  be  bestowed  upon 
the  footing  courses  of  any  building,  and  there  is  no  portion  of  it 
that  needs  closer  inspection  than  the  footings  and  foundation. 

Before  the  masons  commence  actual  operations  the  architect 
should  inspect  all  materials  that  have  been  delivered,  to  see  that 
they  are  of  the  kind  and  quality  specified. 

The  mortar,  together  with  the  sand,  cement  or  lime,  should  be 
particularly  examined,  to  see  that  it  has  the  proper  proportions 
of  cement  or  lime,  and  is  well  worked ;  that  the  cement  or  lime 
is  fresh  and  of  the  kind  or  brand  specified ;  and  that  the  sand 
is  clean  and  sharp.  The  building  of  the  foundation  wall  should 
also  be  carefully  watched  to  see  that  the  wall  is  well  tied  together 
with  plenty  of  three-quarter  and  through  bond-stones,  and  that  the 
inside  is  solidly  filled  with  stone  and  mortar. 

The  superintendent  must  also  examine  the  wall  occasionally  to 
see  that  it  is  built  straight  and  plumb,  and  that  the  general  bed  of 
the  courses  is  horizontal. 

When  inspecting  stonework  already  built,  but  which  has  not  had 
time  for  the  mortar  to  harden,  a  light  steel  rod,  about  ^/^g  inch  in 
diameter  and  4  or  5  feet  long,  will  be  found  useful.  If  the  rod  can 
be  pushed  down  into  the  center  of  the  wall  more  than  18  inches  or 
2  feet  in  any  place  it  shows  that  the  stones  have  not  been  lapped 
over  each  other,  and  if  this  can  be  done  in  several  places  the  in- 
spector should  order  the  wall  taken  down  and  rebuilt.  The  rod  will 
also  indicate  to  a  considerable  extent  whether  or  not  the  stones  in 
the  center  of  the  wall  have  been  well  bedded,  for  if  this  is  not  the 
case,  they  will  rock  or  tip  when  struck  with  the  rod. 

The  inspection  of  a  foundation  wall  cannot  be  too  thorough,  as 
there  is  nothing  that  causes  an  architect  so  much  trouble  as  settle- 
ments in  the  foundations  of  his  buildings. 

125.  FILLING  IN. — In  buildings,  in  which  the  cellar  floor  is  6 
feet  or  more  below  the  ground  level,  the  trenches  behind  the  walls 
should  not  be  filled  in  until  the  floor  joists  are  on  and  the  walls  built 
6  feet  or  more  above  them,  or  until  the  walls  are  solidly  braced  with 
heavy  timbers,  as  otherwise  the  walls  may  be  sprung  by  the  pressure 
of  loose  dirt.   In  heavy  clay  soils  it  is  a  good  idea  to  fill  in  back  of 


DAMPXESS  IN  CELLAR  WALLS. 


109 


the  walls  with  coarse  gravel,  stone  spalls  and  sand,  as  frost  will  not 
''heave"  them  as  it  does  clay. 

126.  HOLES  FOR  SOIL-PIPES  AND  SUPPLY  PIPES.— 
In  thick  walls  built  of  heavy  stone,  the  architect  should  locate  the 
position  of  the  soil-pipes  and  supply  pipes,  and  see  that  openings  are 
left  in  the  proper  places  for  the  pipes  to  pass  through  them. 

7.    DAMPNESS  IN  CELLAR  WALLS 

127.  GENERAL  CONSIDERATIONS.— In  many  localities  it 
is  necessary  to  guard  against  dampness  in  cellar  walls,  particularly 
in  buildings  where  the  basement  is  used  for  living-rooms  or  for 
storage.  There  are  several  devices  for  preventing  moisture  from 
entering  walls,  some  being  applications  on  the  outside  and  others 
being  constructive  devices. 

Where  surface  water  only  is  to  be  provided  against,  and  the 
ground  is  not  generally  saturated  with  water,  coating  the  outside  of 
the  wall  with  asphalt  or  Portland  cement  will,  in  most  cases,  prove 
a  preventative  against  dampness. 

128.  DAMP-PROOFING  CELLAR  WALLS.— Asphalt,  ap- 
plied vv'hile  boiling  hot  to  the  outside  of  a  wall,  is  generally  con- 
sidered a  lasting  and  durable  coating.  To  insure  perfect  protection^ 
the  wall  should  be  built  as  carefully  as  possible,  the  joints  well 
pointed  and  the  vvhole  allowed  to  dry  before  the  coating  is  applied. 

The  asphalt  should  be  applied  in  two  or  more  coats  and  carried 

down  to  the  bottom  of  the  footings. 

If  the  soil  is  wet  and  generally 
saturated  with  water,  moisture  is 
apt  to  rise  in  the  wall  by  absorption 
from  the  bottom.  To  prevent  this, 
two  or  three  thicknesses  of  asphal- 
tic  felt,  laid  in  hot  asphalt,  should 
be  bedded  on  top  of  the  footings, 
just  below  the  basement  floor,  as 
shown  by  the  heavy  line,  Fig.  77. 

Portland  cement  may  be  used  in 
place  of  asphalt  if  the  ground  is 
not  exceedingly  damp ;  but  if  it  is 
often  saturated  with  water,  asphalt 
should  be  used.  The  objections  to 
Portland  cement  are  that  it  is  easily 
fractured  by  any  settlement  of  the 


Fig.   77.    Cellar   A\'aH,  Damp-Proofed 
and  Drained. 


no 


BUILDING  CONSTRUCTION. 


(Ch.  Ill)' 


walls,  and  being  to  some  degree  porous,  suiters  from  the  action  of 
frost. 

Common  coal-tar  also  is  often  used  for  coating  cellar  walls.  It 
answers  the  purpose  very  well  for  a  time,  but  gradually  becomes 
brittle  and  crumbles  away. 

129,  WATERPROOFING  BASEMENTS.— It  is  frequently 
necessary  in  cities  to  construct  dry  basements  in  those  localities  in 
which  water  permeates  the  soil  to  within  a  few  feet  of  the  sidewalks. 

In  such  cases  it  is  necessary  not  only  to  make  the  walls  and  floors 
waterproof,  but  also  to  give  sufficient  thickness  to  the  floors  that  the 
buoyant  force  of  the  water  will  not  cause  it  to  break  through. 

To  make  the  cellar  water-tight,  its  entire  area  should  be  covered 
with  concrete  from  3  to  6  inches  thick,  after  the  footings  of  the 
walls  and  piers  are  in,  so  that  it  will  be  level  with  the  top  of  the 
footings.  A  narrow  course  of  brick  or  stone  should  then  be  laid 
along  the  middle  width  of  the  footings  to  form  a  break,  as  shown 
in  Fig,  78.  Upon  the  top  of  the  footings  three  thicknesses  of 
tarred  felt  or  burlap  should  then  be  mopped  with  hot  asphalt, 
the  felt  being  allowed  to  project  6  inches  on  each  side.  A  similar 
layer  of  felt  and  asphalt  should  be  laid  over  the  footings  of  all  piers, 
'engine  foundations,  etc.,  and  allowed  to  project  at  least  6  inches  on 
all  sides. 

After  the  exterior  walls  are 
completed,  and  before  ^'filling  in," 
the  projecting  felting  should  be 
turned  up  against  them  and 
mopped  with  hot  asphalt ;  and 
the  entire  outside  surfaces  to  the 
sidewalk  line  should  be  covered 
with  three  thicknesses  of  felt  laid 
breaking  joints  in  hot  asphalt  and 
overlapping  the  felt  coming 
through  the  walls.  For  further 
protection  this  covering  is  also 
frequently  plastered  with  i  to  2 
Portland  cement  mortar. 

Before  the  completion  of  the  building  the  entire  cellar  floor,  also, 
should  be  covered  with  felt  in  hot  asphalt,  laid  in  at  least  three 
thicknesses,  breaking  joint  and  overlapping  the  felt  first  laid.  On 
the  top  of  the  felt  thus  laid  there  should  then  be  laid  Portland 


A5phalt| 

Cement^ 


WalL 


if" 


BrcK 'orCoricrete'^ 


•m 


footingrg 


vr 


Fig. 


78. 


Water-Proofed    Basement  Wall. 


DAMPNESS  IN   CELLAR  WALLS. 


lit 


cement  concrete  at  least  i  inch  thick,  for  each  3  inches  in  depth  of 
the  water  above  the  level  of  the  cellar  bottom,  with  a  minimum 
depth  of  6  inches. 

The  following  description  of  the  waterproofing-  of  the  basement 
of  the  Herald  building,  in  New  York  City,  is  given  as  an  actual 
example  of  the  above  method  :* 

In  this  building  the  printing  presses  are  placed  in  the  basement,  and 
great  pains  were  taken  to  exclude  moisture  below  grade.  The  footings  and 
outside  basement  walls  were  covered  with  four-ply  burlap  mopped  on  solid,, 
commencing  at  the  inner  edge  of  sidewalk  and  back  over  top  of  vault  and. 
down  the  outside  of  the  wall  to  the  bottom  of  the  same,  thence  through 
the  wall  and  turned  up  against  same  for  connection  to  the  waterproof  course. 

Beneath  the  surface  of  the  entire  basement,  including  floor  of  vaults,  the 
best  four-ply  roofing  felt  was  mopped  on  solid,  and  similar  material  was 
used  in  connection  with  all  piers,  extending  in  each  case  through  the  entire 
thickness  of  the  pier  and  beneath  the  entire  surface  of  foundations  for  boilers 
and  machinery. 

The  felt  was  securely  lapped  and  turned  up  around  all  walls.  Above  the 
felt  4  inches  of  concrete  was  laid  in  the  basement  and  16  inches  in  the 
boiler  room. 

If  less  expensive,  hard  bricks  laid  in  cement  mortar  and  at  least 
three  courses  in  thickness,  may  be  used  instead  of  the  concrete  above 
the  felt. 

130.  CONSTRUCTIVE  DEVICES  FOR  DAMP-PROOFING 
FOUNDATION  WALLS.— Of  the  constructive  devices,  the  sim- 
plest is  to  make  the  excavation  about  2  feet  larger  each  way  than 
the  building,  so  that  there  will  be  about  a  foot  or  10  inches  between 
the  bottom  of  the  bank  and  the  wall,  as  shown  in  Fig.  77.  A 
V-shaped  tile  drain  should  be  placed  at  the  bottom  of  these  trenches 
after  the  walls  are  built  and  connected  with  a  horizontal  drain, 
carried  some  distance  from  the  building. 

The  trenches  should  then  be  filled  with  cobbles,  coarse  gravel  and 
sand.  If  the  top,  for  a  distance  of  about  2  feet  from  the  building, 
is  covered  with  stone  flagging  or  cement,  it  will  assist  greatly  in 
keeping  the  walls  dry. 

By  draining  the  soil  in  this  way,  and  by  also  coating  the  walls 
with  asphalt  or  concrete,  perfectly  dry  walls  will  in  most  cases  be 
insured. 

For  greater  protection  of  the  basement  from  dampness,  the  base- 
ment walls  should  be  lined  with  a  4-inch  brick  wall  with  an  air 


*  From  the  Engineering  Record,  July  i,  1893. 


112 


BUILDING  CONSTRUCTION.  (Ch.  Ill) 


space  between  the  main  wall  and  the  lining ;  or  an  area  should  be 
built  all  around  the  outside  walls. 

8.    WINDOW  AND  ENTRANCE  AREAS 

131.   WINDOW  AREAS.— These  features,  although  not  strictly  •' 
parts  of  the  foundations,  are  intimately  connected  wdth  them,  and 
are  generally  included,  in  the  same  contract. 

The  thickness  and  bracing  of  area  walls  has  already  been  con-  . 
sidered  (see  Article  121).    The  materials  and  workmanship  of  the 
walls  should  be  the  same  as  in  the  foundation  w^alls. 

Window  areas  intended  for  light  and  ventilation  should  be  of 
ample  size,  so  as  not  to  obstruct  the  light  more  than  necessary. 

For  small  cellar  windows  sunk  not  more  than  2  feet  below  the 
grade  line,  semi-circular  areas  with  9-inch  brick  walls  give  the 
greatest  durability  at  the  least  expense.  If  an  area  is  3  or  4  feet 
deep,  and  as  many  in  length  and  width,  the  thickness  of  its  walls 
should  be  not  less  than  12  inches  for  brick  and  18  inches  for  stone. 

Area  walls  should  be  coped  with  stone  flagging,  set  in  cement, 
the  edge  of  the  flagging  projecting  i  inch  over  the  faces  of  the 
walls.  If  flagging  cannot  be  obtained  without  great  expense  the  top 
of  the  walls  should  be  covered  with  i  to  i  Portland  cement  mortar, 
about  ^  of  an  inch  thick.  Freestones  and  all  porous  stones  are  not 
suitable  for  area  or  fence  copings. 

An  area  may  be  drained  as  follows :  The  bottom  of  the  area 
should  be  carried  at  least  6  inches  below  the  window  sills  and  should 
be  formed  of  stone  flagging  or  of  bricks  laid  in  cement.  Beneath 
the  bottom  a  small  cesspool  or  sand-trap,  about  8  inches  square, 
should  be  built,  which  should  be  connected  by  a  3-inch  drain  pipe 
with  the  main  drain.  A  cast-iron  strainer  or  drain-plate  should  be 
set  over  the  cesspool,  flush  with  or  a  little  below  the  paving,  so 
that  it  can  be  readily  removed  and  the  cesspool  cleaned. 

Where  the  soil  is  of  gravel  or  of  a  sandy  nature,  a  dry  drain  may 
be  used  for  an  area  at  little  expense.  It  consists  of  a  vertical  piece  of 
salt-glazed  tile  sewer  pipe  carried  from  the  cement  bottom  of  the 
area  to  a  point  below  the  bottom  of  the  footings.  The  lower  end 
is  left  open  and  the  upper  end  is  either  open  or  closed  with  a  perfo- 
rated cover.  The  bottoiri  of  the  area  is  graded  to  the  drain,  and  the 
surface  water  is  carried  away  by  the  pipe  and  allowed  to  seep  into 
the  soil  below  the  footings,  thus  causing  no  damage. 


WINDOW  AND  ENTRANCE  AREAS. 


1^3 


The  footings  of  the  area  walls  should  be  started  as  deep  as  the 
bottom  of  the  cesspool,  both  being  below  the  frost  line. 

132.  ENTRANCE  AREAS.— All  area  steps,  when  practicable, 
should  be  of  stone,  or  of  stone  and  brick  combined.*  When  the  soil 
is  hard  and  compact  and  not  subject  to  heaving  by  frost,  a  short 


Fig.    79.    Entrance   Area.     Stone-and-P>rick  Steps. 

run  of  steps  may  be  economically  built  by  shaping  the  earth  to  the 
rake  of  the  steps  and  building  them  directly  on  the  earth,  laying 
two  courses  of  bricks,  in  cement,  for  the  risers,  and  covering  them 
with  2-inch  stone  treads,  as  shown  in  Fig.  79.   All  parts  of  the  steps 


A. 

i 


1 

Fig.  80.    Sections  Through  Area  Steps. 


should  be  set  in  cement,  and  well  pointed,  and  the  ends  of  the  treads 
should  be  built  into  the  side  walls. 

If  an  area  is  6  feet  or  more  in  depth,  or  if  the  soil  is  sandy  or  a 
wet  clay,  then  it  must  be  excavated  beneath  the  steps  and  en- 
tirely surrounded  by  a  wall.  The  steps  may  be  formed  of  2-inch 
stone  risers  and  treads,  or  of  solid  stone,  the  ends  in  either  case 
being  supported  by  the  side  walls.  If  of  solid  stone  the  front  of 
each  step  should  rest  on  the  back  of  the  stone  below  it,  as  shown 
at  A,  Fig.  80.    If  built  of  treads  and  risers  they  may  be  arranged 


*  Or  of  reinforced  concrete  (see  Chapters  IX  and  X.) 


t 


114 


BUILDING  CONSTRUCTION.         (Ch.  Ill) 


as  shown  at  either  B  or  C.  The  arrangement  shown  at  B  is  stronger 
than  that  shown  at  C. 

If  the  steps  are  more  than  5  feet  long  a  bearing  wall  or  iron  string 
should  be  built  under  the  middle  of  the  steps. 

Stone  steps  should  always  be  pitched  forward  about  ]4,  of  an  inch 
in  the  width  of  the  tread. 

In  many  localities  plank  steps,  supported  on  plank  strings,  will 
last  for  a  long  time  if  the  ground  is  excavated  below  them  and  the 
area  walled  up  all  around,  and  when  they  decay  it  is  a  small  matter 
to  replace  them. 

The  platform  at  the  bottom  of  the  steps  should  be  of  stone  or 
brick,  set  at  least  4  inches  below  the  sill  of  the  door  giving  entrance 
to  the  building,  and  should  be  provided  with  cesspool,  plate  and 
drain,  as  described  in  Article  131. 

All  outside  stone  steps,  fence  coping,  etc.,  should  be  set  on  a  foun- 
dation carried  at  least  2  feet  below  grade,  and  in  localities  affected 
by  frost  below  the  freezing  line. 


133.    CONSTRUCTION    OF    VAULTS    UNDER  SIDE- 


WALKS.— Vaults  are  often  built  under  entrance  steps  and  porches, 


the  walls  of  the  vaults  forming  the  foundations  for  the  steps  and 
platforms.  The  roofs  of  the  vaults  are  generally  formed  of  brick 
arches,  two  rowlocks  in  thickness,  with  the  stone  steps  set  in 
cement  mortar  on  top  of  the  arches. 

Vaults  under  sidewalks  may  be  either  arched  over  with  brick,  the 
top  of  the  arches  levelled  off  with  sand,  cinders  or  concrete,  and  the 
sidewalks  laid  thereon,  or  the  sidewalks  themselves,  if  of  large  stone 
flags,  may  be  made  to  form  the  roofs  of  the  vaults.  In  the  latter  case 
the  joints  of  the  stone  slabs  are  closely  fitted  and  often  rebated,  then 
calked  with  oakum  to  within  about  2  inches  of  the  top  and  the 
remaining  space  filled  with  hot  asphalt  or  asphaltic  mastic.  This 
makes  a  tight  job  for  a  time,  but  in  the  course  of  two  or  three 
years  the  joints  need  to  be  cleaned  out  and  refilled. 

Any  form  of  fire-proof  floor  construction  may  also  be  used  for 
covering  sidewalk  vaults  and  a  cement  sidewalk  may  be  finished  on 
top  of  it.  Cement  makes  probably  the  best  walk  and  the  most  dur- 
able construction,  with  a  comparatively  slight  thickness. 

In  San  Francisco  it  has  been  customary  to  build  the  sidewalks  of 
cement,  with  steel  tension-bars  or  cables  imbedded  in  the  bottom, 


9.    PAVEMENT  VAULTS 


PAVEMENTS  AND  SIDEWALKS. 


so  that  the  same  construction  answers  both  for  the  walk  and  for 
the  covering  of  the  vauh. 

If  brick  arches  covered  with  sand  and  a  stone  or  brick  pavement 
are  used,  their  tops  should  be  covered  with  hot  asphalt. 

134.  MUNICIPAL  REGULATIONS  REGARDING 
VAULTS. — In  many  cities  the  building  regulations  will  not  permit 
vaults  to  be  extended  under  sidewalks  unless  certain  restrictions 
are  complied  with.  Generally  vaults  may  be  built  out  to  what  is 
known  as  the  "area-line,"  usually  4  or  5  feet  from  the  building-line, 
but  even  then  there  is  sometimes  a  charge  made  for  this  privilege. 
Where  vaults  are  permitted  to  be  built  out  to  the  curbs  a  consider- 
able fee  is  charged  by  some  cities,  amounting  in  some  cases  to  as 
much  as  twenty-five  dollars  a  running  foot.  It  is  usual  also,  where 
vaults  extend  to  the  curb  line,  to  restrict  their  height,  keeping  their 
roofs  4  or  5  feet  below  the  pavement. 

These  requirements  are  made  by  some  municipalities  in  order  to 
provide  against  interference  with  underground  service  wires,  and 
other  city  installations. 

10.    PAVEMENTS  AND  SIDEWALKS 

135.  GENERAL  CONSIDERATIONS.— Although  these  do 
not  come  under  the  heading  of  foundations  they  are  more  nearly 
related  to  that  class  of  work  than  to  any  other,  and  may  therefore 
be  described  here. 

Pavements  may  be  made  either  of  thin  slabs  of  stone,  called  flag- 
ging, of  concrete,  finished  with  Portland  cement,  or  of  hard  bricks 
made  especially  for  the  purpose. 

When  large  slabs  of  stone  can  be  economically  obtained,  they 
make,  in  the  long  run,  the  most  economical  and  satisfactory  pave- 
ments. 

Smoother  pavements  may  be  made  with  cement.  They  are  prac- 
tically imperishable;  but  should  there  ever  be  occasion  to  cut 
through  them,  or  to  change  the  grade,  the  cement  and  concrete 
must  be  destroyed,  while  the  stone  flagging  can  be  taken  up  and 
relaid,  either  in  the  same  place  or  somewhere  else.  A  stone  side- 
walk can  be  also  be  repaired  more  easily  than  either  of  the  others. 

Stone  Pavements. — As  a  rule  only  stones  that  split  with  com- 
paratively smooth  and  parallel  surfaces  can  be  economically  used 
for  pavements;  for,  if  the  surface  of  the  stone  has  to  be  dressed, 


ii6 


BUILDING  CONSTRUCTION.  (Ch.  Ill) 


Flagging 


C^ffierit 


Section    Through  Stone 
Pavement. 


it  will  generally  be  more  economical  to  use  concrete  and  cement  or 
hard  bricks. 

For  yards  and  areas,  flagging  from  2^  to  3  inches  thick  is  com- 
monly used,  the  edges  of  the  stones  being  trimmed  so  that  they 
will  be  perfectly  rectangular,  and  the  joints  between  them  straight 
and  from  %  to  }i  inch  in  width. 

The  stones  should  be  laid  on  a  

bed  of  sand  not  less  than  2  inches 
thick,  and  the  edges  should  be 
bedded  in  cement,  as  shown  in  Fig. 
81,  extending  3  or  4  inches  under 
them.  On  completion  the  joints 
should  be  thoroughly  filled  with  i  to  i  cement  and  fine  sand,  and 
struck  smooth  with  the  trowel. 

In  localities  where  the  soil  is  dry  and  not  afifected  by  frost,  as  in 
Colorado,  New  Mexico,  etc.,  the  cement  is  generally  omitted  entirely, 
the  stones  being  simply  bedded  in  sand  and  the  joints  filled  with  fine 
sand. 

This  answers  very  well  in  those  localities ;  but  since,  after  a  time, 
grass  and  weeds  commence  to  spring  up  through  the  joints  of 
pavements  in  yards  and  private  walks,  for  first-class  work,  bedding 
in  cement  should  be  specified. 

Stone  sidewalks  are  generally  laid  on  beds  of  sand,  with  the 
joints  in  the  better  class  of  work  bedded  in  cement.  The  stones, 
when  5  feet  long,  should  be  at  least  3  inches  thick,  and  when  8  feet 
long,  5  or  6  inches  thick.  The  best  sidewalks  are  laid  in  one  course, 
unless  exceptionally  wide. 

In  localities  where  the  ground  is  affected  by  frost,  as  it  is  in  most 
of  the  Northern  States,  the  stones,  if.  merely  laid  on  beds  of  sand, 
are  sure  to  become  displaced  and  out  of  level  within  one  or  two 
years.  To  prevent  this,  flagging  stones,  at  least  in  front  of  busi- 
ness buildings,  should  have  a  solid  support  at  each  end. 

Fig.  82  shows  the  manner  in  which  this  is  generally  provided. 


Section  Through  Stone  Sidewalk  and  Supports. 


CEMENT  IVAEKS. 


and  also  the  way  in  which  the  curb  and  gutter  is  supported.  The 
curbstone  should  be  at  least  4  inches  thick,  and  on  business  streets 
6  inches. 

The  dwarf  wall  should  be  about  14  or  16  inches  thick  and  carried 
below  the  frost  line. 

If  the  sidewalk  is  laid  in  two  courses  a  light  wall  of  brick  or 
stone  should  also  be  built  under  the  middle  to  support  the  butting 
ends  of  the  stones, 

136.  CEMENT  WALKS. — Cement  walks  are  extensively  laid 
in  the  Western  States,  even  in  localities  where  excellent  flagging 
stone  is  abundant  and  cement  rather  dear. 

They  are  preferred  on  account  of  their  smooth  and  even  surface. 
When  properly  laid  they  are  also  very  durable.  They  should  be  laid, 
however,  wdiere  there  is  no  danger  of  the  grade  being  altered, 
and  only  after  the  ground  has  become  thoroughly  settled  and  con- 
solidated. 

Their  durability  depends  principally  upon  the  thickness  of  the 
concrete  and  the  quality  of  the  cement. 

Only  the  best  Portland  cement  should  be  used  for  the  finishing, 
although  natural  cements  are  sometimes  used  for  the  concrete.  Port- 
land cement  throughout,  however,  is  to  be  preferred. 

For  first-class  work  cement  walks  should  be  laid  as  follows : 

The  ground  should  be  leveled  off  about  10  inches  below  the  fin- 
ished grade  of  the  walk  and  well  settled  by  tamping  or  rolling.  On 
top  of  this  a  foundation  5  inches  thick  should  be  laid  of  coarse 
gravel,  stone  chips,  sand  or  ashes,  well  tamped  or  rolled  with  a 
heavy  roller.  The  concrete  should  then  be  prepared  by  thoroughly 
mixing  i  part  of  cement  to  i  part  of  sand  and  3  of  gravel,  in  the 
dry  state,  and  then  by  adding  sufficient  water  from  a  sprinkler  to 
make  a  dry  mortar.  The  concrete  should  be  spread  in  a  layer  from  3 
to  4  inches  thick,  commencing  at  one  end,  and  should  be  thoroughly 
tamped.  Before  the  concrete  has  commenced  to  set,  the  top  or  fin- 
ishing coat  should  be  applied,  and  only  as  much  concrete  should  be 
laid  at  a  time  as  can  be  covered  the  same  day.  If  the  concrete  gets 
dry  on  top  the  finishing  coat  will  not  adhere  to  it.  The  top  coat 
should  be  prepared  by  mixing  i  part  of  high  grade  Portland  cement 
with  I  part  of  fine  sand,  or  i  part  of  clean,  sharp,  crushed  granite, 
the  latter  being  the  best.  The  materials  should  be  thoroughly  dry- 
mixed,  and  enough  water  added  to  give  the  consistency  of  plastic 
mortar.    The  coat  should  be  applied  with  a  trowel  to  a  thickness 


ii8 


BUILDING  CONSTRUCTION.    .     (Ch.  Ill) 


of  I  inch  and  carefully  smoothed  and  levelled  on  top  between- 
straight-edges  laid  as  guides.  Used  in  the  above  proportion,  one 
barrel  of  Portland  cement  will  cover  about  40  square  feet  of  con- 
crete. After  the  walk  is  finished  it  should  be  covered  with  straw 
to  prevent  it  from  drying  too  quickly. 

For  brick  paving  see  Article  331  and  "Specifications  for  Brick- 
v^^ork"  in  Chapter  XIIL 

137.  CURBING  FOR  SIDEWALKS.— Granite  or  concrete 
curbs  may  be  used  in  conjunction  with  cement  sidewalks.  Where 
granite  curbs  are  used  they  are  either  6  inches  or  8  inches  in  thick- 
ness, and  from  24  inches  to  36  inches  in  depth.  The  top  surface 
and  exposed  gutter  edge  are  hammer-dressed.  It  is  the  best  modern 
practice,  however,  to  provide  cement-finished  curbs  in  conjunction 
with  well-constructed  cement  pavements.  These  curbs  do  not  as  a 
rule  cost  any  more  than  granite  curbs,  and  can  be  protected  on  the 
edge  with  a  metal  strip. 

In  the  illustration,  Fig.  83, 
is  shown  a  concrete  curb,  the 
edge  being  armored  with 
what  is  known  as  the  ''Wain- 
wright  galvanized-steel  cor- 
ner-bar." It  is  made  with  the 
section  shown  in  the  figure, 
and  is  tied  into  the  concrete 
work  at  intervals  with  anchors 
or  frogs.  A  curb  of  this  kind 
finished,  in  place,  costs  from 
sixty  cents  to  one  dollar  per 
lineal  foot.  Sometimes  con- 
crete curbs  are  reinforced  along  the  edges  with  rolled  steel  chan- 
nels, the  web  of  the  channel  beinsf  vertical.     The  channels  are 

with 


Concrete   Sidewalk  Cvirb, 
Corner-Bar. 


with  Steel 


anchored  to  the 
pronged  anchors. 


concrete   work  at  intervals 


II.    SHORING,  NEEDLING,  UNDERPINNING  AND 

BRACING 

138.  GENERAL  CONSIDERATIONS.— The  direction  of 
these  operations  is  generally  left  to  the  contractor,  as  the  responsi- 
bility for  the  successful  carrying  out  of  the  work  devolves  upon  him. 

The  architect  will  be  wise,  however,  when  such  operations  are  be- 


SHORIXG. 


119 


ing  carried  on  in  connection  with  work  let  from  his  office,  to  see  that 
proper  precautions  are  taken  for  safety,  and  that  all  beams  or  posts 
have  ample  strength  for  the  loads  they  have  to  support.  When 
heavy  or  difficult  work  has  to  be  done,  it  should,  if  possible,  be 
intrusted  to  some  careful  person  who  has  had  experience  in  that 
class  of  work,  as  it  is  a  trade  by  itself. 

139.    SHORING.— This    means  the 
supporting-  of  a  wall  of  a  building  by 
inclined  posts  or  struts,  generally  from 
the  outside,  while  its   foundations  are 
being  carried  down,  or  while  its 
lower    portions  are 
moved   and  girders 
substituted. 

The  usual  method  of  shorin 
the  walls  of  buildings  not 
ceeding  three  stories  in  he 
especially  when  the  shorin 
done  for  the  purpose  of 
holding  up  the  walls  wh 
being  underpinned, 
shown  in  Fig.  84. 

The  props  or  shores 
inserted  in  sockets  cut 
the  wall,  with  their 
lower  ends  resting 
on  timber  cribs 
supported  o  n  the 
ground.  At  least 
two  sets  of  shores 
should  be  used, 
one  to  support  the 
wall  as  low  down 
as  possible  and  the 
other  to  support  it 
as  high,  up  as  pos- 
sible. .  The  latter 
shores  should  not 
have  a  spread  at 
the  bottom  of  more 


Steel  Wedgesc 

ISectioni 


^  ,.  ■■  .  ■    ■   stone.  I    ■  1 


Elevation 

Fig.  84.    Shoring  or  Inclined  Bracing  and  Underpinninj 


I20 


BUILDING  CONSTRUCTION.    ■      (Ch.  Ill) 


than  one-third  of  their  height.     The  platforms  should  be  made 
t  sufficiently  large,  so  as  not  to  bring  too  great  a  pressure  on  the 
ground ;  and  the  shores  should  be  driven  into  place  bv  oak  or 
steel  wedges. 

The  shores  should  be  spaced  according  to  the  height  and  thick- 
ness of  the  wall,  and  all  piers  and  chimneys  should  be  shored.  Gen- 
erally a  spacing  of  6  feet  between  the  shores  will  answer. 

Only  a  part  of  the  foundation  should  be  removed  at  a  time,  and 
as  soon  as  three  sets  of  shores  are  in  place  the  wall  should  be  under- 
pinned, as  described  in  Article  141.  As  fast  as  the  wall  is  under- 
pinned the  first  set  of  shores  should  be  moved  along,  always  keeping 
two  sets  in  place,  and  working  under  or  with  one  set. 

Shoring  may  often  be  successfully  employed  for  holding  up  the 
corner  of  a  building  while  a  pier  or  column  is  being  changed ;  and 
sometimes  when  the  lower  part  of  the  wall  is  to  be  removed  and  a 
girder  slipped  under  the  upper  portion.  In  the  latter  case,  however, 
needling  is  generally  more  successful  and  attended  with  less  risk. 

140.  NEEDLING. — This  term  is  given  to  the  operation  of  sup- 
porting a  wall,  already  built,  on  transverse  beams  or  ''needles" 
placed  in  holes  cut  through  it  and  supported  at  each  end  by  posts, 
jackscrews  or  grillage.  At  least  one  end  of  each  horizontal  beam 
should  be  supported  by  a  jackscrew. 

Wherever  a  long  stretch  of  wall  is  to  be  built  up  at  one  time,  and 
there  is  working  space  on  each  side  of  it,  needling  should  be  em- 
ployed. 

The  beams  must  be  spaced  so  near 
together  that  the  wall  will  not  crack 
between  them,  and  the  size  of  the 
beams  must  be  carefully  proportioned 
to  the  weight  of  the  wall,  floors,  etc. 


Fig.   85.  Needling. 


NEEDLING  AND  UNDERPINNING. 


121 


In  very  heavy  buildings  steel  beams  should  be  used  for  the  needles, 
and  thev  should  be  spaced  not  more  than  2  feet  apart.  In  three- 
or  four-story  buildings  the  needles  may  be  of  large  timbers  spaced 
from  4  to  6  feet  apart.  Each  chimney  or  pier  should  have  one  or 
more  needles  directly  under  it. 

When  the  first  story  walls  or  supports  are  to  be  removed,  the 
beams  or  needles  are  usually  supported  on  long  timbers  having 
screws  under  the  ends ;  or,  if  the  wall  is  very  high  or  thick,  a 
grillage  of  timber  is  built  up  and  the  jackscrews  are  placed  on  top 
of  the  grillage,  the  ends  of  the  needles  resting  on  a  short  beam  sup- 
ported by  two  screws,  in  the  manner  shown  in  Fig.  85. 

When  it  is  desired  fo  remove  the  first  story  wall  of  a  building  for 
the  purpose  of  substituting  posts  and  girders,  or  for  rebuilding  the 
wall,  holes  should  be  cut  in  the  wall  from  4  to  6  feet  apart,  accord- 
ing to  the  weight  to  be  supported  and  the  quality  of  the  brickwork  or 
stonework,  and  at  such  a  height  that  when  the  needles  are  in  place 
they  will  come  a  few  inches  above  the  tops  of  the  intended  girders. 
Solid  supports  should  then  be  provided  for  the  uprights,  the  needles 
put  through  the  wall,  and  posts,  having  screws  in  the  lower  ends,  set 
under  them,  the  bases  of  the  screws  resting  on  the  solid  supports  pre- 
viously provided.  If  the  needles  do  not  have  an  even  bearing  under 
the  wall,  iron  or  oak  wedges  should  be  driven  in  until  all  parts  of 
the  wall  bear  evenly  on  the  needles.  The  jacks  should  then  be 
screwed  up  until  the  wall  is  entirely  supported  by  the  needles,  care 
being  taken,  however,  not  to  raise  the  wall  after  the  weight  is  on  the 
.needles. 

The  wall  below  may  then  be  removed,  the  girders  and  posts  put  in 
place,  and  the  space  between  the  girders  and  the  bottom  of  the  wall 
built  up  with  brickwork,  the  last  course  of  brick  or  stone  being 
made  to  fit  tightly  under  the  old  work.  The  needles  may  then  be 
withdrawn  and  the  holes  filled  up. 

141.  UNDERPINNING. — Underpinning  means  carrying  down 
the  foundations  of  an  existing  building,  or,  in  other  words,  putting 
new  foundations  under  the  old  ones. 

New  footings  may  generally  be  put  under  a  one  or  two-story 
building  resting  on  firm  soil  without  shoring  or  supporting  the 
walls  above,  the  common  practice  being  to  excavate  spaces  of  only 
from  2  to  4  feet  long  under  the  wall,  one  at  a  time,  sliding  in  the 
new  footings  and  wedging  up  with  stone,  slate,  or  steel  wedges. 

Where  the  underpinning  is  to  be  3  feet  or  more  high,  or  where 

i 


122 


BUILDING  CONSTRUCTION.  (Ch.  Ill) 


the  building  is  several  stories  in  height,  the  walls  should  be  braced 
or  supported  by  shores  or  needles. 

The  usual  method  of  underpinning  the  walls  of  buildings  where 
a  cellar  is  to  be  excavated  on  the  adjoining  lot  is  shown  in  Fig.  84. 

Pits  should  first  be  dug  to  the  depth  of  the  new  footings,  and 
timber  platforms  built  as  shown ;  the  shores  should  then  be  put  in 
place  and  wedged  up  with  oak  wedges. 

Sections  about  3  feet  wide  between  the  shores  should  then  be 
excavated  under  the  wall,  new  footing  stones  laid,  and  the  space  be- 
tween the  new  and  old  footings  filled  with  brickwork  or  stonework. 
Where  the  height  between  the  new  and  old  footings  does  not  exceed 
5  feet,  granite  posts,  if  available,  offer  special  advantages  for  under- 
pinning. They  should  be  from  12  to  18  inches  wide  on  the  face  and 
of  a  thickness  equal  to  that  of  the  wall ;  they  should  be  cut  so  as 
just  to  fit  between  the  new  and  old  work,  and  with  top  and  bottom 
surfaces  dressed  square ;  and  they  should  be  set  in  a  full  bed  of  Port- 
land cement  mortar,  with  the  top  joints  also  filled  with  mortar  and 
brought  to  a  bearing  with  steel  wedges. 

If  granite  posts  are  not  available,  good  flat  stones,  or  hard  bricks 
laid  in  cement  mortar  may  be  used  instead,  and  wedged  up  under  the 
old  wall  with  pieces  of  slate  or  steel  wedges  driven  into  the  upper 
beds  of  cement.  Under  heavy  walls  the  latter  wedges  only  should 
be  used.  If  the  bottom  of  the  old  footings  is  of  soft  brickwork, 
pieces  of  hard  flagging,  wnth  full  beds  of  cement  mortar,  may  be 
placed  under  them,  and  the  wedges  driven  under  the  flagging  so  as 
to  bring  the  latter  "hard  up"  under  the  old  work.  The  portions  of 
wall  between  these  sections  should  then  be  underpinned  in  the  same 
way  and  the  shores  moved  along. 

Where  granite  posts  are  used  they  may  be  placed  3  feet  apart  and 
the  space  between  built  up  with  flat  rubble  or  hard  bricks,  wedged 
up  under  the  old  wall  with  slate. 

If  the  soil  under  the  old  building  is  sufficiently  firm,  so  that  it 
will  not  cave  or  ''run  away,"  and  if  there  is  working  space  beneath 
the  lower  floor,  the  ground  may  be  levelled  off,  platforms  of  planks 
and  timbers  placed  on  top  of  it,  and  needles  used  for  supporting 
the  wall,  as  shown  in  Fig.  85.  Where  needles  are  used,  all  of  the 
underpinning  under  the  portion  of  wall  supported  may  be  put  in 
at  the  same  time. 

The  underpinning  should  be  done  as  quickly  as  possible  after  the 
shores  or  needles  are  in  place,  so  as  not  to  require  their  support  for 


NEEDLING  AND  UNDERPINNING. 


123 


a  longer  time  than  necessary.  The  needles  or  shores  should,  how- 
ever, not  be  removed  until  the  cement  has  had  time  to  set. 

142.  NEW  FOUNDATIONS  UNDER  OLD  ONES.— In 
building  modern  tall  office  buildings  foundations  generally  have  to 
go  below  those  of  adjacent  buildings,  and,  the  ground  being  com- 
pressible, new  party-wall  foundations  are  almost  invariably  required. 
The  consequence  is  that  old  walls  have  to  be  supported  while  new 
foundations  are  being  put  under  them.  This  is  usually  done  by 
means  of  steel  needles  placed  from  12  to  24  inches  apart,  their  ends 
resting  on  long  beams  placed  parallel  with  the  wall  and  supported 
by  jackscrews.  Very  often  an  entire  wall  is  supported  in  this  way, 
several  hundred  jackscrews  being  required  for  the  purpose. 


IS 'brick  urati 

J'^  Floor 


"Jack  Jcreu/s, 

Columns  similar  to  the/* 
to  be  prouided  when  neu, 
building  is  put  up  on  this 
side  of  partij  u/alL 


Fig.  86.    Wall  and  Footing,   New  York  Life   Insurance  Company's  Building,  Chicago. 


In  erecting  buildings  of  skeleton  construction  it  is  often  imprac- 
ticable to  remove  old  walls,  and  new  buildings  are  supported  by 
iron  columns  placed  against  walls  and  resting  on  new  foundations 
put  in  under  the  old  ones.  In  building  the  New  York  Life  build- 
ing in  Chicago  such  was  the  case,  and  the  adjacent  wall,  as  shown 
in  Fig.  8^,  was  held  up  by  jackscrews,  which  were  inserted  to 
keep  the  wall  in  place  during  the  settlement  of  the  new  work. 
As  the  new  foundations  settled  the  jacks  were  screwed  up,  so  as  to 
keep  the  old  walls  in  their  original  position.  In  this  case  the  jacks 
were  left  in  place. 

143.  EXAMPLE  OF  HEAVY  NEEDLING  AND  UNDER- 
PINNING.— An  interesting  example  of  foundation  construction 
embodying  the  use  of  needle-beams  in  underpinning,  is  found  in 


124 


BUILDING  CONSTRUCTION. 


(Ch.  Ill) 


Original  3urfa^^ 


6-3k"Bolh 

Fulcnum  Girder -6- 15" ^5'^^^^ 
Oak  ^eparalvrj 


'(hrfi^lever Needles  3-15"!^  £7 ' loncf 


^L/ne  of  Excavation  for 
Underpinning  Old  South 
MeeHnghoU3e 


Bottom  cf  On^inai  Tbunddbn 


Brjck 

Uqderpinning 
I 


Concrete  Invert  of  Tunnel 
Bottom  of  3tation  Eycc^vahon 


Old^  South 
l^leeting  House 

I 


Fig.  87.    Heavy  Needling  and  Underpinning,  Old  South  Meeting  House  and  Old  South 

Building,  Boston. 


connection  with  the  construction  of  the  subway  tunnel  in  Boston. 
The  Washington  Street  tunnel  of  the  Boston  Transit  Commission 
Subway  is  parallel  with  and  close  to  the  front  walls  of  the  Old 
South  Meeting-House  and  Old  South  building.  It  extended  con- 
siderably below  the  foundations  of  both  of  these  buildings,  and  it 
was  necessary  to  provide  an  entrance  to  the  Subway  between  their 
walls. 

Fig.  87  shows  the  ingenious  construction  employed  in  the  opera- 
tion. To  the  left  of  the  figure  is  the  Old  South  building,  which 
is  an  ii-story  and  basement  office-building,  of  modern  steel  con- 
struction ;  to  the  right  of  the  figure  is  shown  the  heavy  masonry 
wall  and  original  foundation  of  the  Old  South  Meeting  House.  In 
proceeding  with  the  operation  the  earth  was  excavated  between  the 
buildings  from  the  original  surface  to  a  depth  of  9  feet.    It  was 


UNDERPIXXIXG.  BRACING. 


125 


necessary  to  underpin  about  80  feet  of  the  wall  of  the  Aleeting- 
House,  and  this  was  done  by  cutting  holes  in  the  walls  at  intervals 
of  15  feet,  and  inserting  needle-beams  consisting  of  three  15-inch 
I-beams,  which  projected  into  the  wall  of  the  Old  South  building, 
and  were  supported  by  the  fulcrum  girder  about  25  feet  long,  con- 
sisting of  six  15-inch  I-beams  supported  on  cribbing  at  each  end. 
The  needle-beams  were  hung  from  this  girder  by  eight  3^-inch 
suspension-bolts,  which  were  drawn  up  tight  until  the  fulcrum 
girder  had  a  deflection  of  about  an  inch.  The  weight  of  the  Old 
South  building  provided  the  reaction  on  the  long  ends  of  the  needles, 
which  acted  as  double  cantilevers.  When  the  wall  was  thus  sup- 
ported, the  new  concrete  foundation  wall  was  put  in  place,  restin.^ 
upon  the  concrete  invert  of  the  tunnel,  and  the  old  wall  of  the  Meet- 
ing-House  was  underpinned  with  brick  between  the  top  of  the  con- 
crete and  the  bottom  of  the  wall.  Each  pier  of  the  Old  South 
building  was  underpinned  separately,  and  was  supported  on  a  needle 
formed  of  six  15-inch  I-beams  set  close  together  under  the  pier, 
and  suspended  from  a  cantilever  fulcrum  girder,  made  with  nine 
15-inch  I-beams.  In  the  same  way,  the  Meeting-House  wall  was 
utilized  fo  provide  the  necessary  reaction  at  the  short  ends  of  the 
cantilevers. 

After  the  weight  of  the  pier  of  the  Old  South  building  had  been 
transferred  to  the  needles,  a  trench  8  feet  long,  parallel  to  the  build- 
ing, was  excavated  under  the  wall  and  the  fulcrum  girders  to  a 
depth  of  35  feet  below  the  street  level,  and  a  concrete  footing  13 
feet  in  height  was  built  in.  This  footing,  or  pier,  was  capped  with 
brickwork,  and  the  old  foundation  wall  brought  to  a  bearing  with 
cast-iron  plates  and  iron  wedges  driven  in.  After  all  of  the  concrete 
piers  were  in  place  the  space  between  was  excavated  and  concrete 
walls  built  between. 

144.  BRACING. — Where  buildings  have  been  built  with  a 
party-wall,  and  one  of  the  buildings  is  torn  down,  leaving  the 
adjacent  walls  unsupported,  they  should  be  protected  from  falling 
by  either  spreading  braces  or  inclined  shores,  according  to  special 
conditions. 

Where  there  is  a  building  on  the  opposite  side  of  the  vacant  lot, 
and  less  than  40  or  50  feet  away,  the  walls  of  both  buildings  may 
be  best  supported  by  spreading  braces,  in  the  manner  shown  in 
Fig  88. 

If  the  distance  between  the  buildings  does  not  exceed  25  feet,  the 


126  BUILDING  CONSTRUCTION.         (Ch.  Ill) 

braces  may  be  arranged  as  shown  at  A  or  B.  If  it  exceeds  25  feet, 
the  braces  must  be  trussed  in  a  manner  similar  to  that  shown  at  C 

Iron  or  steel  rods  are  preferable  for  the  vertical  ties,  as  they 
can  be  screwed  up,  and  any  sagging  caused  by  shrinkage  in  the 
joints  can  be  overcome. 

If  the  buildings  are  very  high  every  other  story  should  be  braced. 
The  ends  of  the  braces  or  trusses  must  be  supported  vertically,  so 
that  they  will  not  slip  down.  When  there  are  offsets  in  the  wall 
they  serve  as  vertical  supports ;  when  there  are  no  offsets,  the 
braces  should  be  supported  by  vertical  posts,  starting  from  the 
foundations,  or  sockets  should  be  cut  in  the  wall  with  corbels  let  in 
and  bolted  through  from  the  inside. 

A  truss  should  be  placed  in  line  with  the  fronts,  and  should  be 
proportioned  so  as  to  resist  the  thrust  from  any  arches  there  may 
be  there.  The  braces  should  be  about  8  by  8  or  10  by  10  inches  in 
section,  with  6  by  12  uprights  against  the  wall,  the  ends  of  the 
braces  being  mortised  into  the  uprights. 

If  there  is  no  wall  opposite  the  building  to  be  braced,  inclined 
braces  must  be  used,  arranged  like  the  shores  shown  in  Fig.  84,  only 
with  a  greater  inclination.  The  ends  of  the  braces  should^)e  brought 
to  a  bearing  by  oak  wedges. 


Fig.  88.    Spreading-Braces  or  Trusses. 


CHAPTER  IV. 


Limes,  Cements  and  Mortars. 


I.    COMMON  LIMES. 

145.  IMPORTANCE  OF  THE  SUBJECT.— There  is  hardly 
any  material  used  by  the  architect  or  builder  upon  which  so  much 
depends  as  upon  mortar  in  its  different  forms,  and  it  is  important 
that  the  architect  should  be  sufficiently  familiar  with  the  different 
kinds  of  limes  and  cements  to  know  their  properties,  and  to  under- 
stand their  adaptation  to  and  suitability  for  different  kinds  of  work. 
He  should  also  be  able  to  judge  of  the  qualities  of  the  materials  with 
sufficient  accuracy  to  prevent  any  which  are  actually  worthless  from 
being  used,  and  he  should  have  some  knowledge  of  mortar  mixing. 

146.  COMMON  LIME. — Common  lime,  sometimes  called  quick- 
lime or  caustic  lime,  has  a  specific  gravity  of  from  2.3  to  3.15,  is  amor- 
phous, somewhat  spongy,  highly  caustic,  quite  infusible,  possesses 
great  affinity  for  water,  and  if  brought  into  contact  with  it  will  readily 
combine  with  about  30  per  cent  of  its  weight,  passing  into  the  con- 
dition of  slaked  or  hydrated  lime  (Ca  Ho  Oo).  It  is  produced  by  the 
calcination  at  moderate  heat  of  limestones  of  varying  composition. 
This  is  done  by  burning  the  stone  in  kilns  of  types  varying  according 
to  the  localities  in  which  they  are  employed.  For  example,  in  the  kilns 
of  one  type,  the  ''continuous,  vertical,  mixed-feed"  kilns,  the  broken 
stone  and  fuel  (generally  coal)  are  put  in  in  layers,  the  fire  lighted 
at  the  bottom',  and  as  the  lime  drops  to  the  bottom  new  layers  of 
stone  and  coal  are  put  in  at  the  top,  so  that  the  kiln  may  be  kept 
burning  for  weeks  at  a  time.  The  carbonic  acid  gas  and  any  moisture 
in  the  stone  are  driven  off  and  allowed  to  escape.  The  limestones 
from  which  limes  and  cements  are  produced  differ  greatly  in  their 
composition,  ranging  from  practically  pure  carbonate  of  lime,  such 
as  oolitic  and  coquina  limestone,  white  chalk  and  marble,  to  stones 
containing  10  per  cent  or  more  of  impurities,  such  as  silica,  alumina 
(clay),  magnesia  (magnesium  oxide),  iron,  and  traces  of  the  alka- 
lies, soda  and  potash.  The  quality  of  the  lime  will  consequently  de- 
pend much  upon  the  percentage  of  impurities  contained  in  the  stone 
from  which  it  is  made.  Strictly  sneaking,  magnesia  should  not  be 
classed  as  an  ''impurity,"  as  it.  simply  se.rves  to  replace  an  equivalent 


127 


128 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


amount  of  calcium  carbonate.  Lime  is  manufactured  in  nearly  every 
State  in  the  Union,  each  locahty  generally  producing  its  own  supply. 
The  only  political  divisions  producing  exceedingly  small  quantities 
of  lime  or  no  lime  at  all  are  Delaware,  Louisiana,  Mississippi,  New 
Hampshire,  North  Dakota  and  the  District  of  Columbia. 

There  is  considerable  difference,  however,  in  the  limes  of  different 
localities,  and  before  using  a  new  lime  the  architect  should  make 
careful  inquiries  regarding  its  quality,  and  if  it  has  not  been  much 
used  it  would  be  better  to  procure  a  lime  of  known  quality,  at  least 
for  plastering  purposes ;  for  common  mortar  it  is  not  necessary  to 
be  so  particular. 

For  commercial  purposes  limes  have  been  classified  as  follows : 
'Group  A. — High-calcium  limes :  Limes  containing  less  than  5  per 
cent  of  magnesia.  The  limes  of  this  group  differ  among 
themselves  according  to  the  amount  of  silica,  alumina,  iron, 
etc.,  contained.  A  lime  carrying  less  than  5  per  cent  of  such 
impurities  is  a  'fat,'  or  'rich'  lime,  as  distinguished  from  the 
more  impure  'lean'  or  'poor'  limes." 

■^'Group  B. — Magnesian  limes :  Limes  containing  over  5  per  cent 
{usually  30  per  cent  or  over)  of  magnesia.  These  limes  are 
all  slower  slaking  and  cooler  than  the  high-calcium  limes  of 
the  preceding  group,  and  they  appear  to  make  a  stronger 
mortar.  They  are,  however,  less  plastic  or  'smooth,'  and  in 
consequence  are  disliked  by  workmen.  As  commercially  pro- 
duced, they  usually  carry  over  30  per  cent  of  magnesia." 
The  chemistry  of  lime-burning,  reduced  to  its  simplest  terms,  may 

be  expressed  as  follows : 

1.  — For  a  limestone,  absolutely  pure. 

Limestone  (Ca  CO3  -j-  heat  =  Ca  O  (high-calcium  lime)  -|-  CO2 

(carbon  dioxide). 

2.  — For  limestone  containing  magnesium  carbonate,  though  other- 
wise pure: 

Limestone  (Ca  CO3,  Mg  CO3)  +  heat  =  Ca  O,  Mg  O  (magnesian 
lime)  +  CO2  (carbon  dioxide). 

As  an  example  of  commercial  quantitative  values,  100  lbs.  of  pure 
limestone  will  give  56  lbs.  of  quicklime  (CaO)  and  44  lbs.  of  car- 
bon dioxide  (COg)  ;  and  100  lbs.  of  limestone  consisting  of  60  per 
cent  lime  carbonate  and  40  per  cent  magnesium  carbonate,  will  give 


COMMON  LIMES. 


129 


about  34  lbs.  of  lime  (CaO),  19  lbs.  of  magnesia  (MgO)  and  47 
lbs.  of  carbon  dioxide  (COo). 

In  the  Eastern  cities  lime  is  sold  by  the  barrel,  weighing  for  Rock- 
land, Me.,  lime  220  lbs.  net;  but  in  many  parts  of  the  country  it  is 
sold  in  bulk,  either  by  the  bushel  or  by  weight.  When  shipped  in 
bulk  it  is  generally  sold  by  the  bushel  of  80  lbs.,  2^  bushels  or  200 
lbs.  of  lime  being  considered  as  equivalent  to  a  barrel.  Other 
weights  are  230  lbs.  net  per  barrel,  .75  lbs.  per  bushel,  and  64  lbs. 
per  cubic  foot. 

The  following  are  average  quantitative  equivalents  for  one 
barrel  of  lime :  2^  barrels  of  paste,  mortar  silfticient  for  laying 
3  perch  of  rubble  stone  or  1,000  to  1,200  bricks,  plaster  for  28 
yards  of  3-coat  work  or  for  40  yards  of  2-coat  work. 

Lime  will  keep  for  a  long  time  in  bulk  when  the  climate  is  very 
dry,  but  it  soon  slakes  in  damp  climates,  for  example,  along  the 
sea  coasts,  unless  enclosed  in  barrels. 

147.  CHARACTERISTICS  OF  GOOD  LIME.— Good  lime 
should  possess  the  following  characteristics:  i.  Freedom  from 
cinders  and  clinkers,  with  not  more  than  10  per  cent  of  other  im- 
purities. 2.  It  should  be  in  hard  lumps,  with  but  little  dust.  3.  It 
should  slake  readily  in  water,  forming  a  very  fine,  smooth  paste, 
without  any  residue.    4.  It  should  dissolve  in  soft  water. 

There  are  some  limes  which  leave  a  residue  consisting  of  small 
stones  and  silica  and  alumina  in  the  mortar  box,  after  the  lime  is 
drained  off.  Such  limes  may  answer  for  making  mortar  for  build- 
ing masonry,  but  should  not  be  used  for  plastering  if  a  better 
quality  of  lime  can  be  procured. 

148.  SLAKING  AND  MAKING  INTO  MORTAR.— The  first 
step  in  the  manufacture  of  lime  mortar  consists  in  the  slaking  of  the 
lime.  During  the  operation  of  lime-slaking  the  chemical  combina- 
tion that  takes  place  may  be  expressed  by  the  formula:  Lime 
(CaO)  +  water  (H2O)  —  lime  hydrate  (CaOoHg).  Lime  hydrate 
is  a  fine  white  powder,  with  specific  gravity  of  2.078.  When  quick- 
lime is  slaked  at  the  building  operation,  the  ordinary  practice  is  to 
do  the  slaking  either  by  putting  the  lime  in  a  water-tight  box  and 
adding  water  through  a  hose  or  by  pails,  or  by  forming  on  a  plank 

•  floor  or  on  a  bed  of  sand,  a  circular  wall  of  sand,  shovelling  into  the 
ring  thus  formed  the  lime,  and  turning  on  the  water  from  a  hose. 
When  the  process  of  slaking  is  completed  the  slaked  lime  is  covered 
with  a  layer  of  sand  until  wanted.    Different  limes  require  different 


I30 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


volumes  of  water  for  slaking.  The  water  is  rapidly  absorbed  by 
the  lime,  causing  a  great  elevation  of  temperature,  the  evolution  of 
hot  and  slightly  caustic  vapor,  and  the  bursting  of  the  lime  into 
pieces;  and  finally  the  lime  is  reduced  to  a  powder,  the  volume 
which  is  from  two  to  three  and  a  half  times  the  volume  of  the 
original  lime.  In  this  condition  the  lime  is  said  to  be  slaked  and  is 
ready  for  making  into  mortar.  The  best  limes  slake  without  leaving 
a  residue.  The  mortar  is  made  by  mixing  clean,  sharp  sand  with  the 
slaked  lime  in  the  proportion  of  i  part  of  lime  to  from  2  to  5  of  sand 
by  volume.  The  New  York  Building  Code  requires  that  not  more 
than  4  parts  of  safid  to  i  part  of  lime  shall  be  used.  Practically  the 
proportion  of  sand  is  seldom,  if  ever,  measured,  but  the  sand  is 
added  till  the  person  mixing  the  mortar  thinks  it  is  of  the  proper 
proportion.  For  brickwork  over  a  certain  proportion  of  sand  cannot 
well  be  added,  for  if  there  is  too  much  sand  in  the  mortar  it  will 
stick  to  the  trowel  and  will  not  work  easily.  With  stonework  the 
temptation  is  always  to  add  too  much  sand,  as  sand  is  generally 
cheaper  than  lime.  The  architect  or  superintendent  should  take  pains 
to  make  himself  familiar  with  the  appearance  of  good  mortar,  so 
that  he  can  readily  tell  at  a  glance  if  it  has  too  much  sand.  Mortar 
that  contains  a  large  proportion  of  lime  is  said  to  be  rich ;  if  it  has 
a  large  proportion  of  sand  and  works  hard  it  is  said  to  be  stiff,  and 
to  make  it  work  more  readily  it  is  tempered  by  the  addition  of  water. 
Tempered  mortar  looks  much  richer  than  stiff  mortar,  though  it 
may  not  be  so.  If  the  mortar  slides  readily  from  the  trowel  it  is  of 
good  quality,  but  if  the  mortar  sticks  to  the  trowel  there  is  too 
much  sand  in  proportion  to  the  lime.  The  color  of  the  mortar 
depends  much  upon  the  kind  and  color  of  the  sand  used. 

Some  limes  when  slaked  leave  a  residue  of  stones,  lumps  and 
gravel,  so  that  instead  of  mixing  the  mortar  in  the  same  box  in  which 
the  lime  is  slaked,  a  larger  proportion  of  water  is  added,  and  the 
slaked  lime  and  water  (about  as  thick  as  cream)  is  run  off  through 
a  fine  sieve  into  another  box,  in  which  the  mortar  is  mixed..  Such 
lime  does  not  make  as  good  mortar  as  that  which  leaves  no  impuri- 
ties, but  it  is  sometimes  used  in  ordinary  brickwork  and  stonework. 

The  general  custom  in  making  lime  mortar  has  been  to  mix  the 
sand  with  the  lime  as  soon  as  the  latter  is  slaked  and  to  let  it  stand  • 
until  required  for  use.    Much  stronger  and  better  mortar  will  be 
obtained,  however,  if  the  sand  is  not  mixed  with  the  slaked  lime  until 
the  mortar  is  needed. 


COMMON  LIMES. 


148a.  HYDRATED  LIME.— When  quicklime  is  slaked  on  the 
work,  it  is  usually  done  by  careless  laborers  in  a  very  indifferent 
manner,  and  the  slaked  lime  seldom  reaches  a  condition  of  theo- 
retical efficiency.  In  order  to  overcome  this  difficulty,  ready-slaked 
lime,  carefully  prepared  at  the  lime-plants,  has  been  introduced  dur- 
ing recent  years.  This  is  placed  on  the  market  under  the  names 
of  '^new-process  lime,"  ''hydrated  lime,"  *iimoid,"  etc.  Its  manu- 
facture involves  the  grinding  of  the  lump  quicklime  to  a  fairly  uni- 
form, small  size ;  the  thorough  mixing  of  the  resulting  grains  of 
powder  with  the  proper  proportion  of  water ;  and  the  teduction  of 
the  slaked  lime  to  a  uniform  fine  powder  by  passing  it  through  a 
sieve  or  by  using  other  methods. 

The  product  is  generally  sold  in  either  heavy,  closely  woven  bur- 
lap or  duck  bags,  containing  100  pounds,  20  bags  to  the  ton,  or  in 
paper  bags  containing  40  pounds,  50  bags  to  the  ton.  It  gains  in 
weight  during  the  process  of  manufacture,  one  ton  of  quicklime 
(2000  pounds)  giving  from  2400  to  2600  pounds  of  hydrated  lime. 

148b.  HYDRATED  LIME  AND  PORTLAND  CEMENT 
MIXED. — Very  interesting  tests  have  been  made  on  the  strength 
of  a  mixture  of  hydrated  lime  and  Portland  cement,  and  the  results 
show  some  very  interesting  data.  Up  to  certain  limits  the  addition 
of  hydrated  lime  to  Portland  cement  mortar  makes  the  latter  easier 
to  work  and  more  plastic ;  but  the  most  interesting  result  noticed  is 
an  actual  increase  in  tensile  strength  when  the  addition  does  not 
exceed  10  or  20  per  cent. 

149.  SAND. — The  reason  sand  is  used  in  mortar  is  because  it 
prevents  excessive  shrinkage  and  reduces  the  cost  of  the  lime  or  the 
cement ;  and  while  its  addition  to  cement  mortar  always  weakens  it, 
its  addition  to  lime  mortar  in  the  proportion  of  i  to  2,  for  example, 
adds  to  the  latter's  strength. 

Sand  is  obtained  from  river  beds,  from  the  seashore  and  from 
banks  or  pits.  Pit  or  bank  sand,  clean,  is  generally  considered  the 
best  for  mortar.  Excellent  sand,  however,  is  often  obtained  from 
river  beds.  The  objection  to  sea  sand  is  the  alkaline  salt  it  contains, 
which  attracts  and  retains  moisture  and  causes  dampness  in  walls. 
The  usual  specifications  for  sand  used  in  making  mortar  require 
that  it  shall  be  angular  in  form,  of  various  sizes,  and  absolutely  free 
from  all  dust,  loam,  clay,  earthy  or  vegetable  matter,  and  also  from 
large  stones. 

Recent  tests  and  experiments,  however,  seem  to  lead  engineers  to 


132 


BUILDING  CONSTRUCTION. 


(Ch. 


the  following  conclusions :  ( i )  It  is  not  necessary  to  have  the 
grains  sharp;  (2)  the  coarseness  of  the  grains  governs  largely  the 
quality;  (3)  in  mortars  loam  or  clay  is  sometimes  injurious,  and 
sometimes  beneficial,  at  least  in  cement  mortars ;  (4)  the  pouring 
of  water  into  sand  does  not  accurately  determine  the  voids,  which 
can  be  found  by  weighing  the  sand  and  finding  its  moisture;  (5)  be- 
cause of  the  effect  of  varying  degrees  of  moisture,  a  study  of  voids 
does  not  result  in  a  method  of  comparing  sands;  (6)  dry  sand  meas- 
ured loose  is  heavier  than  moist  sand;  (7)  when  mixed  with  cement 
coarse  sand  nfakes  a  denser  mortar  and  requires  less  water  than  fine 
sand;  (8)  fine  sand  with  grains  of  uniform  size,  and  screened 
coarse  sand  when  dry,  have  nearly  the  same  weight,  but  with  ordi- 
nary moisture  fine  sand  is  lighter  and  more  porous  than  coarse  sand ; 
(9)  the  weight  of  mixed  sand  is  usually  greater  and  the  volume  of 
voids  smaller  than  that  of  coarse  or  fine  sand. 

It  is  generally  necessary  to  pass  the  sand  through  a  screen  to 
secure  the  proper  degree  of  fineness.  For  rough  stonework  a  com- 
bination of  coarse  and  fine  sand  makes  the  strongest  mortar.  For 
pressed  brickwork  it  is  necessary  to  use  very  fine  sand.  The  archi- 
tect or  superintendent  should  carefully  inspect  the  sand  furnished 
fcr  the  mortar,  and  if  he  wishes  to  test  its  cleanliness,  a  handful  put 
in  a  tumbler  of  water  will  at  once  settle  the  question,  as  the  dirt  will 
separate  and  rise  to  the  top.  Another  simple  method  of  testing  sand  is 
to  squeeze  some  of  the  moist  sand  in  the  hand,  and,  if  upon  opening 
the  hand  the  sand  is  found  to  retain  its  shape,  it  must  contain  dirt  or 
loam  or  clay,  but  if  it  falls  down  loosely  it  may  be  considered  as 
clean.  Sand  containing  loam  or  clay  is  usually  rejected  and  ordered 
from  the  premises,  and  it  is  safe  for  the  architect  to  work  on  the 
principle  that  loam  or  clay,  if  in  sufiicient  quantity  to  be  detected  by 
the  touch,  or  appearance,  or*  by  leaving  a  stain  when  rubbed  between 
damp  hands,  is  harmful,  and  tends  to  weaken  the  cementing  material 
in  the  case  of  most  lime  mortars,  whatever  may  be  the  effect  of  small 
percentages  in  the  case  of  certain  cement  mortars.  As  a  rule,  it  is 
better  that  the  sand  should  be  too  coarse  than  too  fine,  as  the  coarse 
sand  takes  more  lime  and  makes  the  stronger  mortar.  Some  masons 
attempt  the  use  of  fine  sandy  loam  in  their  mortar,  as  it  takes  the 
place  of  lime  in  making  the  mortar  work  easily ;  but  it  generally 
tends  to  weaken  the  mortar,  and  it  is  better  not  to  permit  its  use. 

The  specific  gravity  of  dry  sand  may  be  taken  at  2.65. 

150.    WHITE  AND  COLORED  MORTARS.— White  and  col- 


COMMOX  LIMES. 


133 


ored  mortars  to  be  used  in  laying  face  bri(?lvs  should  l)c  made  from 
lime  paste  or  putty  and  finely  screened  sand.  After  the  slaked  lime 
has  stood  for  several  days  the  water  evaporates  and  the  lime  thickens 
into  a  heavy  paste,  much  like  putty,  from  which  it  takes  its  name 
of  'iime  putty."  By  the  time  the  putty  is  formed  the  lime  should  be 
well  slaked  and  have  no  tendency  to  swell  or  "pop."  Colored  mortar 
is  made  by  the  addition  of  mineral  colors  to  the  white  mortars.  Col- 
ored mortar  should  never  be  made  with  freshly  slaked  lime,  but  only 
with  lime  putty  at  least  three  days  old.  For  IMortar  Colors  see 
Articles  216  to  219. 

Clear  lime  putty  may  be  kept  for  a  long  time  in  casks,  for  use  in 
making  colored  mortar,  only  a  little  mortar  being  made  up  at  a  time. 
Common  lime  when  slaked  and  evaporated  to  a  paste  may  be  kept  for 
an  indefinite  time  in  that  condition  without  deterioration,  if  pro- 
tected from  contact  with  the  air  so  that  it  will  not  dry  up.  It  is  cus- 
tomary to  keep  the  lime  paste  in  casks  or  in  the  boxes  in  which  it 
was  slaked,  covered  over  with  sand,  to  be  subsequently  mixed  with 
it  in  making  the  mortar. 

151.  SETTING  OF  LIME  MORTAR.— Lime  mortar  does  not 
set  like  cement  mortar,  but  gradually  absorbs  carbonic  acid  from  the 
air  and  becomes  in  time  very  hard ;  the  process,  however,  requires 
from  six  months  to  several  years,  according  to  the  thickness  of  the 
mortar  and  its  exposure  to  the  atmosphere.  If  permitted  to  dry  too 
quickly  it  never  attains  its  proper  strength.  If  frozen,  the  process 
of  setting  is  delayed  and  the  mortar  is  much  injured  thereby.  Alter- 
nate freezing  and  thawing  will  entirely  destroy  the  strength  of  the 
mortar.  Lime  mortar  will  not  harden  under  water,  nor  in  continu- 
ously damp  places,  nor  when  excluded  from  contact  with  the  air. 

In  regard  to  all  the  phenomena  of  the  process  of  the  setting  of 
lime  mortar  in  their  minutest  details,  there  does  not  seem  to  be  as 
yet  a  complete  unanimity  of  opinion  on  the  part  of  those  who  have 
made  the  subject  one  of  special  study.  There  is  a  general  agreement 
that  the  chemical  changes  take  place  for  the  most  part  at  the  outer 
and  exposed  portion  of  the  lime-mortar  joints,  and  that  the  mortar  in 
the  interior  of  a  wall  never  acquires  what  might  be  called  **com- 
plete  hardness,"  or  at  least  not  until  after  the  lapse  of  long  periods 
of  time. 

Some  investigators,  for  example,  emphasize  the  fact  of  the  prob- 
able chemical  action  that  takes  place  between  the  sand  and  the  lime, 
and  the  resulting  formation  of  lime  silicates ;  while  others  claim  that 


134  BUILDING  CONSTRUCTION.  (Ch.  IV) 


the  effect  of  this  is  very  'IHght  and  of  Httle  engineering  importance. 

One  authority,  Mr.  Edwin  C.  Eckel,*  states  that  ''the  hardening 
of  Hme  mortars  is  a  simple  process.  It  may  be  accepted  as  proven 
that  lime  mortars  harden  by  simple  recarbonation,  the  lime  gradually 
absorbing  carbon  dioxide  from  the  atmosphere,  and  becoming,  in 
fact,  artificial  limestone.  As  this  absorption  can  take  place  only  on 
the  surface  of  the  masonry,  the  lime  mortar  in  the  interior  of  a  wall 
never  becomes  properly  hardened.  In  this  process  the  sand  of  the 
mortar  takes  no  active  part.  It  is  merely  an  inert  material,  added 
solely  in  order  to  prevent  shrinkage  and  consequent  cracking." 

Professor  Clifford  Richardson,  one  of  the  highest  authorities  on 
questions  of  this  kind,  says : 

*'The  setting  of  lime  mortar  is  the  result  of  three  distinct  processes 
which,  however,  may  all  go  on  more  or  less  simultaneously.  First, 
it  dries  out  and  becomes  firm.  Second,  during  this  operation,  the 
calcic  hydrate,  which  is  in  solution  in  the  water  of  which  the  mortar 
is  made,  crystallizes  and  binds  the  mass  together.  Hydrate  of  lime 
is  soluble  in  831  parts  of  water  at  78°  Fahr. ;  in  759  parts  at  32°  and 
in  1 136  parts  at  140°.  Third,  as  the  per  cent  of  water  in  the  mortar 
is  reduced  and  reaches  five  per  cent,  carbonic  acid  begins  to  be 
absorbed  from  the  atmosphere.  If  the  mortar  contains  more  than 
five  per  cent  this  absorption  does  not  go  on.  While  the  mortar  con- 
tains as  much  as  0.7  per  cent  the  absorption  continues.  The  resulting 
carbonate  probably  unites  with  the  hydrate  of  lime  to  form  a  sub- 
carbonate,  which  causes  the  mortar  to  attain  a  harder  set,  and  this 
may  finally  be  converted  to  a  carbonate.  The  mere  drying  out  of 
mortar,  our  tests  have  shown,  is  sufficient  to  enable  it  to  resist  the 
pressure  of  masonry,  while  the  further  hardening  furnishes  the 
necessary  bond." 

Mr.  C.  F.  Mitchellf  gives  a  simple  statement  of  the  chemistry 
of  lime  mortar  setting,  as  follows : 

''The  setting  of  lime  depends  on  the  absorption  of  CO2  from  the 
atmosphere  by  the  particles  of  slaked  lime  in  solution  in  the  mortar, 
the  carbon  dioxide  being  soluble  in  water.  The  CaO  and  CO2  com- 
bine to  form  crys.tals  of  CaCOg,  these  being  deposited,  and  giving 
up  the  H2O,  which  combines  with  the  next  particle,  forming  it  into 
a  saturated  solution,  rendering  it  into  the  necessary  condition  to 
take  up  another  molecule  of  CO, ;  this  in  its  turn  crystallizes  and 


*  "Cements,  Limes  and  Plasters."  Edwin  C.  Eckel. 
+  "Building  Construction."    Charles  F.  Mitchell. 


COMMOX  LIMES. 


135 


is  deposited ;  this  process  is  repeated  till  the  whole  has  set.  The 
crystals  always  have  a  tendency  to  adhere  to  something  rough  and 
hard,  such  as  sandy  particles  or  the  surfaces  of  bricks ;  for  this 
reason  the  addition  of  sand  up  to  a  certain  ratio  increases  the 
strength  of  the  mixture,  the  best  ratio  being  one  part  pure  lime  to 
one  of  sand,  the  maximum  being  one  of  pure  lime  to  three  parts 
of  sand. 

long  time  elapses  before  pure  limes  harden,  owing  to  their 
depending  upon  external  aid  to  attain  this  state.  If  lime  alone  were 
used  the  surface  would  set  and  form  an  impervious  layer,  and  so 
check  the  CO2  from  acting  on  those  particles  below  the  surface,  the 
moisture  in  which  evaporates  and  leaves  the  same  in  the  state  of  a 
powder;  and  even  when  a  large  proportion  of  sand  is  used  and  the 
mass  made  porous,  the  supply  of  COg  must  necessarily  be  small,  and 
a  long  time  elapses  before  the  material  hardens.  Pure  lime  mortar 
built  in  thick  walls  never  hardens  nor  sets,  but  crumbles  into  a  friable 
powder. 

'Tor  this  reason  pure  limes  should  be  avoided  for  constructional 
work,  and  a  lime  or  cement  which  does  not  depend  on  external  aid 
to  set  be  used." 

152.  PRESERVING  LIME.— Fresh  burned  lime  will  readily 
absorb  moisture  from  a  damp  atmosphere,  and  will  in  time  become 
slaked,  thereby  losing  all  of  its  valuable  qualities  for  making  mortar. 
It  is  therefore  important  that  great  care  should  be  taken  to  secure 
freshly  burned  lime  and  to  protect  it  from  dampness  until  it  can  be 
used.  If  the  lime  is  purchased  in  casks  it  should  be  kept  in  a  dry 
shed  or  protected  by  canvas,  and  if  it  is  bought  in  bulk  it  should  be 
kept  in  a  water-tight  box  built  for  the  purpose. 

On  no  account  should  the  superintendent  permit  the  use  of  air- 
slaked  lime,  as  it  is  impossible  to  make  good  mortar  with  it. 

153.  DURABILITY  OF  LIME  MORTAR.— Good  lime  mortar, 
when  protected  from  moisture,  has  been  considered  by  many  archi- 
tects to  have  sufficient  strength  for  ordinary  brickwork  above  ground, 
except  when  heavily  loaded,  as  in  piers.  It  continues  to  grow  harder 
and  stronger  for  many  years  after  it  is  in  place.  The  writer  knows 
of  old  walls  in  which  the  lime  mortar  was  as  strong  as  the  bricks, 
and  where  the  adhesion  of  the  mortar  to  the  bricks  was  greater 
than  the  cohesion  of  the  particles  of  the  bricks. 

A  specimen  of  mortar,  supposed  to  be  the  most  ancient  in  exist- 
ence, obtained  from  a  buried  temple  on  the  island  of  Cyprus,  was 


136  BUILDING  CONSTRUCTION.  (Ch.  IV) 


found  to  be  hard  and  firm,  and  upon  analysis  appeared  to  be  made 
of  a  mixture  of  burnt  lime,  sharp  sand  and  gravel,  some  of  the  frag- 
ments being  about  ^  an  inch  in  diameter.  The  lime  was  almost 
completely  carbonized."^' 

Lime  mortar,  however,  attains  its  strength  slowly,  and  where  high 
buildings  are  built  rapidly  the  mortar  in  the  lower  story  does  not 
have  time  to  get  sufficiently  hard  to  sustain  the  weight  of  the  upper 
stories,  and  for  such  work  cement  should  be  added  to  the  lime  mortar. 

Some  cities  limit  the  use  of  lime  mortar  to  the  brickwork  of  chim- 
neys in  frame  buildings,  but  the  building  laws  of  many  cities  allow 
its  use  in  all  but  fire-proof  buildings.  The  allowable  stress,  however, 
is  limited,  for  example,  in  the  case  of  brick  piers  in  one  case,  to  seven 
tons  per  square  foot. 

For  the  brickwork  of  ordinary  buildings,  and  for  light  rubble  foun- 
dations, lime  and  natural  cement  mortar  forms  a  suitable  and  fre- 
quently used  mixture ;  and  when  a  still  superior  quality  and  strength 
are  wanted,  lime  and  Portland  cement  mortar  is  used.  Beyond  these 
come  the  natural  and  Portland  cement  mortars  without  the  lime. 

2.    HYDRAULIC  LIMES. 

154.  GENERAL  DESCRIPTION.— Hydraulic  limes  are  those 
containing,  after  burning,  enough  lime  to  develop,  more  or  less,  the 
slaking  action,  together  with  sufficient  of  such  foreign  constituents 
as  combine  chemically  with  lime  and  water,  to  confer  an  appreciable 
power  of  setting  under  water,  and  without  access  of  air. 

The  process  of  setting  is  entirely  different  from  that  of  drying, 
which  is  produced  simply  by  the  evaporation  of  the  water.  Setting 
is  a  chemical  action  which  takes  place  between  the  water,  lime  and 
other  constituents,  causing  the  paste  to  harden  even  when  under 
water. 

Hydraulic  lime  or  cement  should  not  be  used  after  it  has  com- 
menced to  set,  as  the  setting  will  not  take  place  a  second  time  and 
the  strength  of  the  mortar  will  be  lost. 

In  the  hydraulic  limes  used  for  making  mortar,  the  constituent 
which  confers  hydraulicity  is  clay,  or  more  correctly,  the  silica  con- 
tained in  the  clay. 

Mr.  Edwin  C.  Eckel  statesf  that  "theoretically  the  proper  compo- 
sition for  a  hydraulic  limestone  should  be  calcium  carbonate  86.8 


♦William  Wallace,  Ph.D.,  F.  R.  S.  E.,  in  London  Chemical  Nervs,  No.  281. 
t  "Cements,  Limes  and  Plasters."    Edwin  C.  Eckel. 


HYDRAULIC  LIMES. 


137 


per  cent  and  silica  13.2  per  cent.  The  hydraulic  limestones  in  actual 
use,  however,  usually  carry  a  much  higher  silica  percentage,  reaching 
at  times  to  25  per  cent,  while  alumina  and  iron  are  commonly  present 
in  quantities  which  may  be  as  high  as  6  per  cent.  The  lime  content 
of  the  limestones  commonly  used  varies  from  55  per  cent  to  65  per 
cent." 

The  same  authority  gives'^  another  definition  of  hydraulic  limes  as 
follows :  "The  hydraulic  limes  include  all  those  cementing  materials 
(made  by  burning  siliceous  or  argillaceous  limestones)  whose  clinker 
after  calcination  contains  so  large  a  percentage  of  lime  silicate  (with 
or  without  aluminates  and  ferrites)  as  to  give  hydraulic  properties 
to  the  product,  but  which  at  the  same  time  contains  normally  so  much 
free  lime  (CaO)  that  the  ma^s  of  clinker  will  slake  on  the  addition 
of  water." 

Commercial  as  well  as  theoretical  differences  make  it  convenient  to 
divide  the  true  hydraulic  limes  into  two  groups,  the  classification 
depending  upon  the  extent  to  which  the  so-called  impurities  of  the 
limestone  are  present,  reduce  the  slaking  action,  and  confer  upon  the 
lime  the  property  of  setting  under  water.   These  groups  are 

1.  Eminently  hydraulic  limes. 

2.  Feebly  hydraulic  limes. 

.  During  the  calcination  of  the  eminently  hydraulic  limes  a  by- 
product is  produced.  This  is  usually  put  on  the  market  separately, 
and  is  known  as  ''grappier  cement." 

By  treating  the  feebly  hydraulic  limes  with  sulphuretic  acid  accord- 
ing to  the  formulas  of  a  special  process  developing  new  properties, 
a  secondary  product  results,  which  also  is  marketed  separately  as 
''selenitic  lime,"  or  ''Scott's  cement."  This  cement  cannot  compete 
with  the  excellent  natural  cements  of  the  United  States. 

The  following  is  an  analysisj  of  a  typical  hydraulic  lime,  after 


slaking : 

Silica  (Si  O^)   22.0 

Alumina  (Al^  O3)   2.0 

Iron  Oxide  (Fe^  O3)   2.0 

Lime  (Ca  O)   62.0 

Magnesia  (Mg  O)   1.5 

Sulphur  trioxide  (S  O3)   0.5 

Carbon  dioxide  (C  O^)   0.0  ) 

Water    lo.o  f 


100.0 

*  American  Geologist,  March,   igo-',  p.  152. 

t  Le  Chatelier,  Trans.  Am.  Inst.  Min.  Engrs.,  vol.  22,  p.  16. 


138 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


Artificial  hydraulic  lime  can  be  manufactured  by  mixing  together, 
in  proper  proportions,  soft  chalk  or  thoroughly  slaked  common  lime  . 
and  unburnt  clay,  then  burning  and  grinding  in  much  the  same 
manner  as  in  the  manufacture  of  Portland  cement ;  but  as  the 
process  of  manufacture  is  nearly  as  expensive  as  for  making  Port- 
land cement  it  is  more  profitable  to  make  cement,  on  account  of 
its  superior  hydraulic  energy. 

A  very  simple  experiment  will  determine  if  a  lime  is  hydraulic  or 
not :  Make  a  small  cake  of  the  lime  paste,  and  after  it  has  com- 
menced to  stiffen  in  the  air,  place  it  in  a  dish  of  water  so  that  it  will 
be  entirely  immersed.  If  it  possesses  hydraulic  properties  it  will 
gradually  harden,  but  if  it  is  not  hydraulic  it  will  soften  and  dissolve. 

Limestones  with  a  composition  suitable  for  making  hydraulic  lime 
are  very  common  in  England  and  on  the  Continent  of  Europe,  the 
siliceous  and  argillaceous  limestones  of  Teil,  in  France,  being  among 
the  most  noted.  As  hydraulic  limes  are  usually  only  feebly  hydraulic 
when  compared  with  good  natural  cements  or  Portland  cements,  and 
as  the  United  States  is  rich  in  materials  suitable  for  the  manufacture 
of  natural  cements,  these  hydraulic  limes  have  never  been  manu- 
factured in  this  country  and  they  have  never  been  known  as  an  article 
of  commerce,  although  the  importations  each  year  are  considerable. 

155.  LAFARGE  CEMENT. — Among  the  non-staining  cements, 
the  Lafarge  Cement  is  the  best  known,  and  has  been  on  the  American 
market  for  many  years.  It  is  a  grappier  cement  of  very  satisfactory 
composition,  made  at  Teil,  France,  and  belongs  in  the  class  of  emi- 
nently hydraulic  limes.  These  latter  and  the  grappier  cements  have 
a  relatively  small  percentage  of  iron  and  soluble  salts,  and  besides 
being  light  colored,  do  not  stain  masonry,  built,  for  example,  of 
marble,  limestone  and  other  porous  stones.  They  are  unlike  Portland 
and  Rosendale  cement  in  this  respect,  and  hence  are  especially  desir- 
able in  setting  such  stones. 

This  non-staining  property  is  possessed  also  by  some  of  the  foreign 
Puzzolan  cements. 

For  setting  large  stones,  mix  i  part  by  volume  of  lime  paste  to  4 
parts  of  the  cement,  to  retard  the  setting  of  the  cement  until  the 
stones  are  well  bedded. 


NATURAL  CEMENTS, 


139 


The  following  are  the  analyses  of  two  typical  Lafarge  cements* : 

(I)  (2) 

Silica  (Si  O^)                                           3110  27.38 

Alumina  (Al^  O3)                                   (4.43  2-6i 

Iron  Oxide  (Fe^  O3)                                (  2.15  1.02 

Lime  (Ca  O)                                        58.38  58.38 

Magnesia  (Mg  O)                                     1.09  0.46 

Alkalies  (K^  O,  Na^  O)                              0.94  n.  d. 

Sulphur  trioxide  (S  O3)                             0.60  0.43 

Carbon  dioxide  (C  O^)                             j  1.28  j  n.  d. 

Water                                                    (  n.  d.  (  n.  d. 

156T  NON-STAINING  CEMENTS  IN  GENERAL.—The 
following  is  a  typical  specification  for  these  cements:  "Non-stain- 
ing cement  n^ust  be  of  a  brand  that  has  been  in  use  for  at  least 
two  years  to  test  its  non-staining  qualities,  have  a  specific  gravity 
of  not  less  than  2.75,  contain  not  more  than  2  per  cent  of  sulphuric 
acid,  nor  more  than  3  per  cent  of  magnesia,  be  of  such  fineness  that 
85  per  cent  will  pass  through  a  No.  100  standard  sieve,  and  in  bri- 
quettes of  neat  cement,  when  tested  as  usually  specified  for  Port- 
land cement,  have  a  tensile  strength  of  200  pounds  per  square  inch. 
All  cement  must  be  of  uniform  quality,  and  when  delivered  must 
be  in  original  packages  with  the  brand  and  maker's  name  marked 
thereon,  and  must  be  kept  dry." 

3.    NATURAL  CEMENTS. 

157.  -CLASSIFICATIONS  OF  CEMENTING  MATE- 
RIALS.— Cementing  materials  in  general  may  be  classified  as 
I,  Common  Limes;  2,  Hydraulic  Limes;  3,  Natural  Cements;  4, 
Portland  Cements ;  5,  Puzzolans  or  Slag  Cements. 

They  also  naturally  fall  into  two  groups;  non-hydraulic  cement- 
ing materials  and  hydraulic  cements.  To  the  first  group  belong 
Plaster  of  Paris,  Keene's  Cement,  cement  plaster,  common  lime,  etc., 
and  to  the  second  group  belong  all  but  the  first  of  the  above  men- 
tioned five  subdivisions.  Having  considered  the  common  limes 
and  the  hydraulic  limes,  the  natural  cements  will  be  considered  in 
the  next  article. 

A"  comparison  of  the  compositions  of  the  different  cementing 
materials,  excluding  the  plasters,  will  aid  in  making  the  basis  of 
the  classification  clear,  and  the  following  is  a  tablef  giving  some 
typical  analyses: 

*  (i.)  C.  F.  McKenna,  analyst,  1897. 

*(2.)  Engineering  News,  vol.  47,  p.  23.,  Jan.  9,  1902. 

t  "Concrete,  Plain  and  Reinforced."     Taylor  and  Thompson. 


I40 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


TABLE  IX. 
Typical  Analyses  of  Cements. 


Portrnd 
Cement 


'Si 


Silica  (Si  Oa>  

Alumina  (AI2  O3)  

Iron  Oxide  (Fe^  O3)  

Calcium  Oxide  (Ca  O)  

Magnesian  Oxide  (Mg  O), 

Sulphuric  Acid  (S  O3)  

Loss  on  Ignition  

Other  Constituents  


31.31 

2.53 
62.89 
2.64 
1.34 
1.39 
0.75 


Natural  Cement 


American 


c3  O 


21.931 
5.98 
2.35 

62.92 
1.10 
1  54 
2.91 


18.38 

15.20  - 

a5.84 
14.02 
0.93 
3.73 
11.46 


^3 


Eng 


French 


20.42 
4.76 
3.40 
46.64 
12.00 
2.57 
6.75 
3.74 


25.48 
10.30 

7.44 
44.54 

2  92 

2;6i 

3.68 
1.46 


2^.60 
8.90 
5.30 

52.69 
1.15 
3.25 
6.11 


26.5 
2.5 
1.5 

63.0 
1.0 
0.5 
5.0 


28.95 
.40 
.54 
.29 
.96 


If 


21.70 
3.19 
0.66 
60.70 
0.85 
.37  0.60 
.39  13.20 
.30  0.10 


1.  W.  F.  Hildebrand,  Society  of  Chemical  Industry,  1902,  Vol.  XXI. 

2.  W.  F.  Hildebrand,  Journal  American  Chemical  Society,  1903,  25,  1180. 

3.  Clifford  Richardson,  Brickbuildcr,  1897,  p.  229. 

4.  Stanger  &  Blount,  Mineral  Industry,  Vol.  V,  p.  69. 

5.  Candlot,  Ciments  et  Chaux  Hydrauliqu^s,  1898,  p.  174. 

6.  Le  Chatelier,  Annales  des  Mines,  September  and  October,  1893,  p.  36. 

7.  Report  of  the  Board  of  U.  S.  Army  Engineers  on  Steel  Portland 
Cement,  1900,  p.  52. 

8.  Candlot,  Ciments  et  Chaux  Hydrauliques,  1898,  p.  24. 

9.  Rockland-Rockport  Lime  Company. 
10.  Western  Lime  and  Cement  Company. 

158.  DEFINITION  OF  NATURAL  CEMENT.— Natural 
cement  is  the  product  resulting  from  the  burning  and  subsequent 
pulverization  of  a  natural  clayey  limestone  containing  from  15  to 
40  per  cent  of  silica,  alumina  and  iron  oxide.  There  is  no  prelimi- 
nary mixing  and  grinding.  The  temperature  of  the  burning  is  about 
that  of  the  ordinary  lime-kiln,  and  not  sufBcient  to  cause  vitrifica- 
tion. Almost  all '  of  the  carbon  dioxide  is  driven  ofif,  there  is  a 
combination  of  the  lime  with  the  silica,  alumina  and  iron  oxide,  and 
the  formation  of  a  mass  containing  silicates,  aluminates  and  ferrites 
of  lime ;  or  in  case  the  original  rock  contains  magnesium  carbonate, 
the  formation  of  magnesia  and  magnesian  compounds.  As  this 
resulting  mass,  as  it  comes  from  the  kiln,  will  not  slake  if  water  be 
poured  on  it,  it  is  ground  into  a  fine  powder,  which,  when  mixed 
with  water,  hardens  or  sets  rapidly  either  in  air  or  in  water.  The 
property  of  hydraulicity,  as  in  the  case  of  all  silicate  cements,  is  due 
principally  to  the  formation  of  tricalsic  silicate  (3CaO,  Si02). 


NATURAL  CEMENTS, 


141 


159.  EARLY  USE  OF  NATURAL  CEMENTS.— Cements 
in  general  have  been  used  from  the  earhest  known  civiHzations. 
The  Egyptians,  Carthagenians  and  Romans  knew  their  properties 
and  employed  them  in  their  works.  Recent  discoveries  seem  to 
point  to  a  practical  knowledge  of  their  value  possessed  by  the 
ancient  peoples  of  Mexico  and  Peru.  After  an  apparent  general 
loss  of  the  art  of  their  manufacture  during  the  Middle  Ages  and 
early  modern  times,  it  appears  to  have  been  rediscovered  about 
the  middle  of  the  eighteenth  century,  on  the  occasion  of  the  build- 
ing of  the  Eddystone  lighthouse,  when  John  Smeaton,  the  en;^ineer 
in  charge,  produced  a  good  hydraulic  lime  or  natural  cement  from 
argillaceous  limestones.  In  England,  again,  just  at  the  beginning 
of  the  nineteenth  century,  the  so-called  "Roman  Cement,"  a  natural 
cement  made  by  calcining  and  grinding  nodules  of  clayey  lime  car- 
bonate, called  "septaria,"  found  in  the  clay,  was  introduced  by 
Joseph  Parker.  About  this  time  natural  cement  was  manufactured 
in  France.  The  first  natural  cement  made  in  the  United  States  was 
that  manufactured  for  use  in  the  building  of  the  Erie  Canal.  It 
came  from  a  natural  rock  in  New  York  State,  Madison  County,  and 
was  introduced  by, Canvas  White  in  1818.  The  increase  in  its  use 
was  steady  from  that  time  until  about  1900,  since  which  date  there 
has  been  a  decline  in  the  output,  caused  by  the  reduction  in  cost  and 
consequent  increase  in  use  of  American  Portland  cement.  The  pro- 
duction of  natural  cement  in  1906  was  4,055,797  barrels,  valued  at 
$2,423,170,  and  declined  as  compared  with  the  output  of  the  pre- 
ceding year.  The  industry  fluctuated  between  a  production  of 
7,000,000  and  8,000,000  barrels  from  1900  to  1904,  when  it  fell  to 
a  little  more  than  4,500,000  barrels.  In  1905  it  decreased  to  a  little 
less  than  4,500,000  barrels. 

160.  DISTRIBUTION  OF  NATURAL  CEMENTS  IN  THE 
UNITED  STATES. — "In  no  other  country  in  the  world  is  there  to 
be  found  cement  rock  formations  which  are  at  all  to  be  compared 
with  those  so  well  distributed  throughout  the  United  States.  .  .  . 
Here  we  have  immense  beds  of  cement  rock  absolutely  free  from 
any  extraneous  substances,  perfectly  pure  and  clean,  with  layer  upon 
layer,  extending  for  thousands  of  feet  without  appreciable  variation 
in  the  proportion  of  the  ingredients."* 

There  is  a  very  wide  distribution  throughout  the  United  States, 
geologically  and  geographically,  of  clayey  limestones  whose  chemical 

*  TJriah  Cummings  in  the  Brickbuilder. 


BUILDIXG  COXSTRUCTION.  (Ch.  IV) 


composition  is  such  that  they  may  be  used  in  the  manufacture  of 
natural  cement,  and  this  product  has  been  made,  in  small  or  large 
amounts,  and  at  different  periods,  in  almost  every  State  in  the  Union. 
But  in  order  that  a  natural  cement  industry  may  become  well  estab- 
lished  in  any  given  locality,  the  rock  maist  be  fairly  steady  in  chem- 
ical composition  throughout  the  strata,  the  material  must  be  cheaply 
mined  or  quarried,  the  cost  of  fuel  must  not  be  too  high,  freight 
must  be  reasonable  and  a  steady  local  demand  prevail.  It  is  the 
absence  of  these  requisites  in  many  districts  where  there  are  valuable 
natural  cement  rock  deposits  which  explains  the  reason  for  the 
relatively  few  localities  in  which  this  industry  has  become  concen- 
trated. 

The  cement  is  commonly  known  by  the  name  of  the  place  from 
which  the  stone  is  obtained,  although,  as  there  are  often  several 
manufactories  in  the  same  locality,  there  may  be  several  brands  of 
cement  made  from  the  same  rock.  The  difference  in  the  quality  of 
such  brands  is  often  due  to  the  care  exercised  in  their  manufacture. 

The  principal  localities  arranged  by  States  in  which  natural 
cements  are  made  in  the  United  States  are  as  follows : 

Nezv  York. — "In  the  State  of  New  York  natural  cement  is  manufactured 
in  four  localities.  In  the  order  of  their  importance  they  are:  (i)  the  Rosen- 
dale  district  in  Ulster  County,  (2)  the  Akron-Buffalo  district  in  Erie  County, 
(3)  the  Fayetteville-Manlius  district,  for  the  most  part  in  Onondaga  County, 
.and  (4)  at  Howe's  Cave  in  Schoharie  County." 

The  term,  "Rosendale  Cement,"  has  been  heard  in  New  York  and  New 
England  more  frequently  than  the  term  "Natural  Cement,"  because  Rosendale, 
Ulster  County,  N.  Y.,  was  one  of  the  towns  in  which  this  cement  was  first 
made.  As  a  matter  of  fact,  for  a  time,  all  natural  cements  in  the  United 
States  were  called  "Rosendale  Cement."  Owing  to  the  length  of  time  for 
which  it  has  been  used,  and  the  special  advantages  enjoyed  for  transportation 
and  nearness  to  the  great  building  centers  of  the  country,  Rosendale  cement 
has  perhaps  been  more  widely  known  than  any  other  of  the  natural  cements. 
The  New  York  cements  are  generally  of  a  very  good  quality  and  well  suited 
for  building  operations. 

Indiana-Kentucky.— 'The.  plants  of  the  'Louisville  district'  are  for  the 
most  part  located  in  Indiana,  though  one  or  two  mills  are  in  operation  on 
the  Kentucky  side  of  the  Ohio  River."  It  is  probably  the  leading  natural 
cement  beyond  the  Alleghenies,  the  product  being  exceeded  only  by  the 
production  from  New  York  State.  There  are  several  brands  of  this  cement 
in  the  market,  and  they  find  their  way  as  far  west  as  the  Rocky  Mountains. 

Illinois.— NesiT  Utica,  La  Salle  County,  Illinois,  a  natural  cement  has 


*  For  a  very  complete  account  of  the  distribution  of  the  American  Natural-cement 
Rocks,  and  detailed  analyses  of  the  same,  see  "Cements,  Limes  and  Plasters,"  by  Edwin 
C,  Eckel. 


NATURAL  CEMENTS. 


143 


been  manufactured  since  1838.  This  cement  has  always  stood  well  in  public 
favor,  and  is  largely  used  throughout  the  West. 

Wisconsin. — "Two  plants  in  Wisconsin  are  engaged  in  the  manufacture 
of  natural  cement  from  a  clayey  magnesian  limestone,  located  north  of  Mil- 
waukee, near  the  Lake." 

Minnesota. — A  cement  rock  of  good  quality  exists  at  Mankato,  and  the 
manufactured  product  has  obtained  a  foothold  in  the  markets  of  the  Northwest. 
There  is  a  second  plant  located  at  Austin. 

Georgia. — "Two  natural  cement  plants  are  located  in  Northwest  Georgia, 
but  they  use  cement  rocks  from  two  different  geological  formations,  and  their 
raw  materials  and  products  differ  widely  in  composition."  The  cement  manu- 
factured from  stone  quarried  at  Cement,  Bartow  County,  "probably  has  no^ 
superior  in  this  country.  Used  as  an  exterior  plaster  on  a  house  in  Charleston 
in  1852,  the  stucco  still  remains  unimpaired,  while  the  sandstone  lintels  over 
the  windows  have  long  since  been  worn  away." 

Kansas. — A  natural  cement  has  been  manufactured  near  Fort  Scott  since 
1867.  A  bed  of  natural  cement  rock,  feet  thick,  outcrops  at  this  place.  It 
is  a  dark-colored,  fine-grained,  compact  limestone  of  the  Carboniferous  age, 
and  extends  for  a  considerable  distance  throughout  the  State. 

North  Dakota. — A  lo-foot  bed  of  soft,  chalky  limestone  rock  of  the 
Cretaceous  age  is  being  mined  for  a  natural  cement  plant  located  in  Cavalier 
County. 

Ohio. — At  different  points  in  Ohio,  notably  at  Defiance  and  New  Lisbon, 
there  are  some  small  natural  cement  plants.  At  the  former  plant  a  black 
calcareous  shale  of  the  Devonian  age  is  used,  and  in  regard  to  this  Mr. 
Edwin  C.  Eckel  states  in  his  "Cements,  Limes  and  Plasters"  that  if  published 
analyses  be  correct,  this  rock  is  by  far  the  most  argillaceous  material  used 
anywhere  for  this  purpose. 

Texas. — Two  natural  cement  plants  have  been  started  in  Texas,  but  the 
analyses  published  would  seem  to  show  that  the  product  obtained  by  burning 
a  rock  of  the  chemical  composition  indicated  would  be  a  weak  hydraulic  lime 
and  not  a  true  natural  cement,  according  to  the  classifications  at  present  in  use. 

An  extended  description  of  the  natural  cements  manufactured  in 
this  country  prior  to  1895  was  given  in  a  series  of  articles  by 
Uriah  Cummings  in  the  Brickbuilder  for  that  year. 

161.  EUROPEAN  NATURAL  CEMENTS.— These  are  man- 
ufactured in  almost  all  the  countries  of  Europe,  but  as  the  products 
are  inferior  to  the  little  less  costly  Portland  cement,  the  latter  are 
gradually  driving  them  out  of  the  market.  They  also  have  to 
compete  with  the  better  class  of  hydraulic  limes. 

European  natural  cements  may  be  divided  into  two  classes,  . 
called   respectively    (i)    ''Natural    Portland   Cements"   and  (2) 
**Roman  Cements." 


144 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


(1)  The  European  natural  Portland  cements  are  made  from  a 
natural  rock  and  have  a  small  percentage  of  magnesia.  They  are 
burned  at  a  fairly  high  temperature,  and  as  regards  their  physical 
properties  and  chemical  analysis,  they  are  somevv^hat  similar  to  the 
true  Portlands.  But  as  they  are  not  very  carefully  and  finely 
ground  artificial  mixtures  made  before  burning,  and  will  not  pass 
any  but  the  low-grade  Portland  tests,  they  cannot  be  classed  with 
the  true  Portland  cements. 

(2)  The  Roman  cements  form  a  second  class  of  European 
natural  cements,  and  they  usually,  although  not  always,  have  a  rela- 
tively low  percentage  of  magnesia  in  their  chemical  composition. 
In  some  respects  these  products  approach  the  best  of  the  American 
natural  cements,  at  least  as  far  as  their  ''cementation  index"  is 
concerned.  In  Belgium  a  quick-setting  cement,  called  a  ''Roman 
Cement,"  is  one  of  the  especial  products  of  the  immense  quarries 
in  the  calcareous  district  of  Tournai.  In  England,  stones  which 
burn  naturally  to  cements  are  to  be  found  to  a  large  extent  in 
certain  districts,  notably  as  rounded  lumps  or  nodules  of  clayey 
lime  carbonate,  and  called  "septaria."  T^ese  nodules  are  embedded 
in  the  clay  of  the  south  of  England,  in  the  shale  beds  of  the  Lias 
formation,  and  along  the  coast  where  they  have  been  washed  out 
of  the  beds. 

The  Roman  cement  sets  very  rapidly,  usually  in  about  fifteen 
minutes  after  mixing ;  has  about  one-third  the  strength  of  true 
Portland  cement ;  and  is  much  weakened  by  the  addition  of  sand, 
which  should  never  be  used  in  a  greater  ratio  than  i  to  i. 

In  speaking  of  the  subject  of  American  and  European  "Natural 
Cements,"  Professor  J.  B.  Johnson  in  his  treatise  on  "The  Materials 
of  Construction"  says :  "There  are  few  suitable  rocks  in  Europe 
for  making  this  cement.  It  is  extremely  irregular  in  composition, 
and  not  to  be  compared  with  the  very  uniform  beds  found  in  inex- 
haustible quantities  in  the  United  States.  If  such  natural  cement 
rocks  as  we  have  had  been  common  in  England  and  on  the  Con- 
tinent, it  is  almost  certain  that  the  artificial  Portland  cement  would 
never  have  been  discovered." 

162.  CHEMICAL  ANALYSIS  OF  SOME  AMERICAN 
NATURAL  CEMENTS.— The  following  table,  giving  the  chemi- 
cal constituents  of  some  of  the  American -natural  cements,  will  be 
found  useful  in  comparing  the  products  from  different  localities': 


NATURAL  CEMEXTS, 


TABLE  X. 

Table  of  Analyses — Natural  Rock  Cements. 


NUMBER. 

SILICA. 

ALUMINA. 

IRON  OXIDE. 

LIME. 

MAGNESIA. 

POTASH 

AND  SODA. 

CARBONIC 
ACID,  WATER. 

24-3^ 

2.61 

6.20 

39-45 

6.16 

5-30 

15-23 

34.66 

5.10 

I  .00 

30.24 

18.00 

6.16 

4.84 

3  

23.  i6 

6.33 

I. 71 

36.08 

20.38 

5.27 

7.07 

4  

26.40 

6.28 

I  .00 

45.22 

9.00 

4.24 

7.86 

5  

25.28 

7-85 

1-43 

44.65 

9-50 

4-25 

7.04 

6  

30.84 

7-75 

2.  II 

34-49 

17-77 

4.00 

3  04 

7  

27.30 

7.14 

1 .80 

35-98 

18.00 

6.80 

2.98 

8  

28.38 

II. 71 

2.29 

43-97 

2.21 

9.00 

2-44 

9  

27.69 

8.64 

2.00 

42. 12 

14-55 

2.00 

3-00 

24-34 

8.56 

2.08 

61 .62 

0.40 

2.00 

0.80 

23.32 

6.99 

5-97 

53-96 

7.76 

2.00 

27.60 

10.60 

0.80 

33-04 

7.  26 

7-42 

2.00 

13  

33-42 

10.04 

6.00 

32.79 

9-59 

0.50 

7.66 

14  

22.58 

7-23 

3-35 

48. 18 

15.00 

3.66 

15  

26.61 

10.64 

3-50 

42. 12 

13. 12 

2.00 

2.01 

I6  

25.15 

8.00 

3.28 

49-53 

13-78 

0.26 

REFERENCE. 

1.  Buf¥aIo  Hydraulic  Cement,  Buffalo,  N.  Y. 

2.  Utica  Hydraulic  Cement,  Utica,  111. 

3.  Milwaukee  Hydraulic  Cement,  Milwaukee,  Wis. 

4.  Louisville  Hydraulic  Cement,  'Tern  Leaf,"  Louisville,  Ky. 

5.  Louisville  Hydraulic  Cement,  "Hulme,"  Louisville,  Ky. 

6.  Rosendale  Hydraulic  Cement,  "Brooklyn  Bridge,"  Rosendale,  N.  Y. 

7.  Rosendale  Hydraulic  Cement,  "Hoffman,"  Rosendale,  N.  Y. 

8.  Cumberland  Hydraulic  Cement,  Cumberland,  Md. 

9.  Akron  Hydraulic  Cement,  "Cummings,"  Akron,  N.  Y. 

10.  California  Hydraulic  Cement,  South  Riverside,  Cal. 

11.  Fort  Scott  Hydraulic  Cement,  "Brockett's  Double  Star,"  Fort  Scott, 

Kansas. 

12.  Utica  Hydraulic  Cement,  La  Salle,  111. 

13.  Shepherdstown  Hydraulic  Cement,  Shepherdstown,  W.  Va. 

14.  Howard  Hydraulic  Cement,  "Howard,"  Cement,  Ga. 

15.  Mankato  Hydraulic  Cement,  Mankato,  Minn. 

16.  James  River  Hydraulic  Cement,  Balcony  Falls,  Va. 

163.  THE  MANUFACTURE  OF  NATURAL  CEMENT.— 
From  a  mechanical  standpoint,  the  manufacture  of  natural  cement 
is  a  comparatively  simple  process,  and  especially  when  compared 
to  that  of  Portland  cement.  It  involves  only  two  general  opera- 
tions, burning  and  grinding. 


146 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


It  is  not  the  province  of  a  work  on  Building  Construction  to  go 
into  detail  regarding  the  manufacture  of  building  materials,  and 
for  full  descriptions  of  the  processes  of  cement  burning  and  grind- 
ing the  reader  is  referred  to  the  many  recent  treatises  on  Limes, 
Cements,  Mortars  and  Concretes.  At  this  point,  however,  a  very 
brief  enumeration  of  the  steps  followed  in  making  natural  cement 
may  be  useful. 

The  limestone  is  usually  stratified,  the  strata  varying  somewhat 
in  chemical  composition,  but  the  rock,  in  its  natural  state,  con- 
tains the  proper  ingredients  for  natural  cement.  For  any  given 
brand  of  cement  it  is  usual  to  mix  several  strata,  so  that  in  case 
there  is  too  much  silica  in  one  layer,  it  will  be  corrected  by  another 
containing  a  surplus  of  lime  or  magnesia.  The  principal  steps  in 
order  in  the  process  of  manufacture  are  as  follows : 

1.  Quarrying  the  rock,  (a)  in  open  cuts,  or  {b)  by  mining  in 
tunnels  and  chambers. 

2.  Breaking  the  rock  into  sizes  conveni^t  for  handling. 

3.  Running  the  rock  through  an  ordinary  rock-crusher,  and 
breaking  it  into  pieces  varying  in  size  up  to  six  inches,  greatest 
dimension. 

4.  Carrying  the  rock,  generally  by  tramway,  to  the  platforms  at 
the  top  of  the  kilns,  which  are  usually  of  the  'Vertical  continuous 
mixed-feed,  type,"  avera^ng  45  feet  in  height  and  16  feet  in 
diameter,  and  built  either  (a)  of  masonry  lined  with  fire-brick,  or 
{b)  of  an  iron  shell, -lined  with  fire-brick. 

5.  Spreading  the  rock  and  fuel  in  the  kiln  in  alternate  layers,  the 
fuel  being  {a)  anthracite  coal,  or  {b)  a  good  quality  of  bituminous 
coal. 

6.  Burning  the  rock  and  fuel,  the  temperature  being  ''somewhat 
greater  than  that  used  for  burning  lime,  but  below  the  point  of 
incipient  fusion  reached  in  burning  Portland  cement." 

'7.  Sorting  out  and  throwing  away  the  underburnt  and  over- 
burnt  clinker,  necessitated  by  the  inevitable  non-uniform  burning, 
and  resulting  in  a  "probable  average  loss  of  about  25  per  cent." 

8.  Conveying  the  sorted  calcined  rock  to  crushing  machines, 
usually  "pot-crackers." 

9.  Conveying  the  crushed  material  to  screens  which  separate  the 
coarse  particles  from  the  cement  that  is  fine  enough  to  pack. 

10.  Grinding  the  coarser  particles  in  the  fine  grinding  machines, 


NATURAL  CEMENTS. 


147 


usually  either  (a)  "edge-runners,"  or  (b)  ball  or  tube-mills,  or  (c) 
ordinary  mills,  or  (d)  emery-faced  stones. 

11.  Passing  the  product  through  the  mixers  to  obtain  greater 
uniformity. 

12.  Conveying  the  product  by.  chutes  to  the  packing  rooms,  and 
packing  it  in  bags  and  barrels. 

164.  THE  USES  OF  NATURAL  CEMENTS.— As  the  use 
of  lime  mortar  is  confined  to  dry  places  where  it  is  exposed  to  the 
air,  being  usually  employed  only  in  the  construction  of  thin  walls 
above  ground  and  in  the  foundation  coats  of  plaster ;  and  as  it 
loses  its  binding  properties  when  exposed  to  dampness,  as  in  base- 
ment walls,  and  when  excluded  from  contact  with  air,  as  in  thick 
walls  ;  and  as  it  sets  too  slowly  to  bear  any  immediate  heavy  weight ; 
cements  have  to  be  added  or  cement  mortars  substituted  to  meet 
these  conditions. 

In  mortar,  natural  cement  is  adapted  to  ordinary  brickwork  not 
subjected  to  high  water  pressure  or  to  contact  with  water  until 
about  one  month  after  laying;  and  for  ordinary  stone  masonry 
v^here  the  chief  requisites  are  weight  and  mass. 

Natural  cement  mortar  or  concrete  should  never  be  allowed  to 
freeze,  should  never  be  laid  under  water,  nor  in  very  exposed  situa- 
tions, nor  in  marine  construction. 

Natural  cement  may  be  substituted  for  Portland  in  concrete,  if 
economy  demands  it,  for  dry  unexposed  foundations  where  the  load 
in  compression  can  never  exceed  about  75  pounds  per  square  inch 
(5  tons  per  square  foot)  and  will  not  be  exposed  until  three  months 
after  placing;  for  backing  or  filling  in  massive  concrete  or  stone 
masonry  where  weight  and  mass  are  the  essential  elements;  for 
subpavements  of  streets  and  for  sewer  foundations. 

Messrs.  Taylor  and  Thompson  in  their  treatise  on  concretes  state 
that  ''mixtures  of  natural  and  Portland  cements,  unless  mixed  at 
the  factory  and  sold  as  improved  natural  hydraulic  cements,  are 
not  advised  under  any  conditions. 

''Mixtures  of  natural  cement  and  lime  mortar  are  suitable  for 
ordinary  building  brickwork,  for  light  rubble  foundations  and  for 
building  walls."* 

"Natural,  quick-setting  cements  are  used  for  reinforced  concrete 
only  in  special  forms  of  construction,  viz.,  in  repair  work,  as  when 
quick  setting  is  necessary  in  order  to  enable  the  structure  to  sustain 

*  "Concrete,  Plain  and  Reinforced."    Taylor  and  Thompson. 


148  BUILDING  CONSTRUCTION.  (Ch.  IV) 


moderate  loads  or  enable  its  use  within  a  few  hours ;  in  hydraulic 
work,  as  in  the  construction  of  reservoirs  and  conduits ;  and  in  the 
construction  of  reinforced  pipe.  They  are,  however,  extensively 
used  for  plain  concrete  work.  Sometimes,  when  quick  setting  with 
great  strength  is  desired,  a  mixture  of  natural  and  Portland 
cements  is  employed."* 

■''While  the  better  grades  of  natural  cement  are  quite  sufficient 
in  strength  for  nearly  all  kinds  of  engineering  works,  the  want  of 
uniformity  in  their  hardening  properties  is  a  serious  objection  to 
their  use."t 

''Natural  cement  mortar  is  used  in  the  construction  of  ordinary 
walls,  sewers,  foundations  for  roadways,  etc.,  when  Portland  is 
considered  too  expensive. "J 

165.  CHARACTERISTIC  PROPERTIES  AND  REQUIRE- 
MENTS OF  NATURAL  CEMENTS.— Facy^a-^^.— Natural 
cement  as  well  as  Portland  cement  is  usually  packed  in  strong  cloth 
or  canvas  sacks,  except  in  cases  where  it  is  to  be  stored  in  damp 
places  or  near  the  sea,  when  it  should  be  packed  in  well-made 
wooden  barrels  lined  with  paper. 

Field  Inspection. — A  general  field  inspection  often  enables  a  cor- 
rect judgment  to  be  formed  of  the  condition  of  the  cement,  which 
is  generally  stored  temporarily  on  raised  platforms  at  the  site  of 
the  construction,  in  ord^r  that  the  necessary  tests  may  be  made. 
The  general  condition  and  marking  of  the  packages  should  be 
observed. 

Sampling. — For  the  purpose  of  testing,  samples  are  taken  from 
the  packages  at  random.  There  are  different  methods  of  sampling. 
Sometimes  each  sample  from  each  package  is  tested  separately, 
and  sometimes  small  samples  are  taken  from  each  of  a  number  of 
packages,  mixed  together,  and  then  separated  again  into  convenient 
sample  lots  for  testing. 

Color. — The  color  of  cement  is  no  criterion  of  quality.  In  a 
natural  cement  it  may  indicate  the  uniformity  or  non-uniformity 
of  a  given  brand  or  grade,  or  differences  in  the  composition  of  the 
rock  used,  or  in  the  degree  of  burning.  There  is  a  great  variation 
in  color  among  the  natural  cements,  and  they  run  from  a  light  yel- 
low to  a  dark  gray  and  sometimes  to  a  chocolate-brown.  The  color 
gives  no  clue  to  the  cementitious  value,  since  it  is  due  chiefly  to 

♦  "Concrete,   and  Reinforced  Concrete  Construction."    Homer  A.  Reid. 
t  "The   Materials   of   Construction."    J.   B.  Johnson. 
%  "Civil  Engineering."    C.  J.  Fiebeger. 


NATURAL  CEMEXTS. 


149 


oxides  of  iron  and  manganese,  which  bear  no  direct  relation  to 
the  cementing  properties.  A  very  light  color  often  may  indicate, 
however,  an  inferior  underburned  natural  cement. 

Weight. — The  specifications  of  the  American  Society  for  Test- 
ing Materials  require  the  packing  in  bags  of  94  pounds,  net,  three 
bags  constituting  a  barrel  of  282  pounds.  A  cement  bag  weighs 
about  one  pound.  In  different  localities,  however,  different  stand- 
ards of  weight  prevail.  The  standard  barrel  of  natural  cement 
weighs  about  320  pounds  gross  or  300  pounds  net  in  the  Rosen- 
dale,  Howe's  Cave,  and  Akron  districts ;  300  pounds  gross  and  280 
pounds,  net,  in  the  Lehigh  district  of  Pennsylvania ;  and  280  pounds 
gross  or  265  pounds,  net,  in  the  Louisville,  Utica,  Milwaukee,  Fort 
Scott  and  other  western  districts.  Again,  these  rules  have  excep- 
tions, the  Howard  cement  of  Georgia,  for  example,  weighing  only 
about  240  pounds  to  an  Eastern  natural  cement  barrel,  and  the 
Pembina  cement  of  North  Dakota  weighing  380  pounds  net  per 
barrel.  The  latter  cement  is  packed  at  about  the  regular  Portland 
cement  weight. 

The  average  weight  of  Louisville  or  Rosendale  cement  is,  per 
cubic  foot,  loose,  50  to  57  pounds;  and  per  cubic  foot,  packed,  from 
74  to  80  pounds. 

Specific  Gravity. — The  specific  gravity  of  a  cement  in  general 
gives  an  indication  of  the  thoroughness  of  burning,^as  it  is  lowered 
by  underburning  and  raised  by  overburning.  It  is  also  lowered 
by  hydration  and  adulteration.  This  test  supplements  the  chemical 
analysis,  since  the  latter  does  not  indicate  the  degree  of  calcination. 
The  specific  gravity  of  natural  cement  is  generally  no  criterion  of 
its  quality,  but,  to  some  degree,  may  be  regarded  as  a  measure  of 
the  uniformity  of  a  single  grade.  The  usual  specification  requires 
that  the  specific  gravity  of  the  natural  cement  thoroughly  dried 
at  ICQ  degrees  Cent.  (212  degrees  Fahr.)  shall  be  not  less  than  2.8. 
Very  few  American  natural  cements  ever  fall  as  low  in  specific 
gravity  as  2.8,  and  they  range  between  2.8  and  3.2,  thus  overlapping 
the  lower  limit  given  for  Portland  cement. 

Activity,  or  Time  of  Setting.— When  water  is  added  to  cement, 
making  a  paste,  the  latter  gradually  hardens,  and  the  rate  of  hard- 
ening is  called  the  "activity"  of  the  cement.  The  time  when  the 
mass  begins  to  harden  is  called  the  "initial  set,-"  and  the  time 
when  the  mass  has  become  so  hard  that  it  cannot  be  distorted  or 
penetrated  without  rupture  is  called  the  "final  set"  or  "hard  set." 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


Certain  definite  limits  must  be  fixed  for  the  time  of  setting,  and  for 
natural  cement  it  is  usually  specified  that  it  shall  develop  initial 
set  in  not  less  than  ten  minutes,  and  hard  set  in  not  less  than  thirty 
minutes,  nor  in  more  than  three  hours.  For  full  descriptions  of  the  * 
apparatus  and  methods  used  to  determine  the  time  of  set,  the  reader 
is  referred  to  the  treatises  on  Cement  Testing,  especially  to  "Prac- 
tical Cement  Testing,"  by  W.  Purves  Taylor. 

The  natural  cements  are  generally  much  quicker  in  setting  than 
the  Portland  cements,  although  slow-setting  natural  cements  are 
occasionally  met  with,  and  a  rapidity  of  set  may  be  changed  by 
aeration,  by  the  addition  of  gypsum  or  plaster,  etc. 

In  case  the  necessary  laboratory  apparatus  for  testing  the  activity 
is  not  at  hand,  for  practical  purposes  the  setting  qualities  of  the 
cement  or  mortar  may  often  be  examined  in  ordinary  construction, 
by  making  up  pats  from  a  number  of  the  packages  and  by  the 
pressure  of  the  thumb  testing  their  hardening.  When  the  surface 
can  no  longer  be  indented,  the  paste  or  mortar  may  be  considered 
to  have  reached  the  stage  of  the  final  set. 

Soundness  or  Constancy  of  Volume. — It  is  the  purpose  of  this 
test  to  determine  in  advance  whether  or  not  the  cement  is  apt  to 
disintegrate,  to  crumble,  expand  or  contract  and  thus  cause  crack- 
ing or  distortion  in  the  masonry.  The  term  ''deformation"  is  em- 
ployed in  France.  A  cement  is  said  to  be  ''sound"  when  it  does  not 
expand  or  contract  or  check  in  setting.  The  principal  causes  of 
unsoundness  are  improper  mixing,  faulty  processes  of  manufacture, 
excess  of  lime,  insufiicient  grinding,  underburning,  the  presence  of 
sulphides,  an  excess  of  magnesia  or  of  the  alkalies,  an  excess  of 
clay  and  insufficient  age.  Tests  for  soundness  are  of  two  kinds : 
(i)  The  Normal  test,  a  pat  being  immersed  in  water  at  70  degrees 
Fahr.  for  28  days,  and  a  similar  pat  kept  in  air  at  ordinary  tem- 
peratures and  observed  at  intervals,  and  (2)  the  Accelerated  test, 
a  pat  being  exposed  in  any  convenient  way  in  an  atmosphere  of 
steam  above  boiling  water,  in  a  loosely  closed  vessel,  for  5  hours. 
This  test  is  usually  considered  as  a  corroborative  test  only,  and  not 
as  final. 

Tests  made  on  pats  of  neat  cement  paste  kept  in  air  and  water 
under  normal  conditions  are  considered  to  be  the  only  conclusive 
ones  for  natural  cements.  In  both  natural  and  Portland  cements 
similar  phenomena  are  noticed  in  regard  to  excessive  expansion, 


NATURAL  CEMENTS. 


checking  or  disintegration  on  normal  pats.  For  natural  cements 
the  accelerated  test  has  not  proved  successful. 

The  usual  requirements  for  constancy  of  volume  of  natural 
cement  are  as  follows:  Pats  of  neat  cement  about  3  inches  in 
diameter,  one-half  inch  thick  at  the  center,  and  tapering  to  a  thin 
edge,  shall  be  kept  in  moist  air  for  a  period  of  24  hours. 

(a)  A  pat  is  then  kept  in  air  at  normal  temperature. 

(b)  Another  pat  is  kept  in  water  maintained  as  near  70  degrees 
Fahr.  as  practicable. 

These  pats  are  observed  at  intervals  for  at  least  28  days,  and  to 
satisfactorily  pass  the  tests  should  remain  firm  and  hard  and  show- 
no  signs  of  distortion,  checking,  cracking  or  disintegration. 

Fineness. — The  finer  a  cement  of  any  class  is  ground  the  better 
its  quality.  The  following  requirement  for  the  ^'fineness"  of 
natural  cement  is  taken  from  the  Standard  Specifications  of  the 
American  Society  for  Testing  Materials :  *Tt  shall  leave  by  weight 
a  residue  of  not  more  than  10  per  cent  on  the  No.  100,  and  30  per 
cent  on  the  No.  200  sieve." 

The  following  are  some  opinions  of  different  engineers  and 
authorities  on  fineness  requirements  of  cements : 

*Tt  is  generally  accepted  that  the  coarser  particles  in  cement  are 
practically  inert,  and  it  is  only  the  extremely  fine  powder  that 
possesses  adhesive  or  cementing  qualities.  The  more  finely  cement 
is  pulverized,  all  other  conditions  being  the  same,  the  more  sand  it 
will  carry  and  produce  a  mortar  of  a  given  strength. 

"The  efifects  of  grinding  upon  cements  are  to  make  them, 

(1)  Stronger  when  tested  with  sand; 

(2)  Weaker  when  tested  neat; 

(3)  Quicker  setting; 

(4)  Capable  of  producing  a  larger  volume  of  paste; 

(5)  Less  affected  by  free  lime. 

"With  the  same  proportions  of  sand  higher  tensile  and  compres- 
sive strength  is  obtained  from  finely  ground  than  coarsely  ground 
cements.  Conversely,,  a  larger  proportion  of  sand  can  be  used  with 
fine-ground  than  with  coarse-ground  cement,  with  the  same  result- 
ing strength."* 

"The  degree  of  fineness  to  which  a  natural  cement  is  ground 
depends  both  upon  the  composition  of  the  material  and  the  process 
of  grinding  used.    At  times  the  percentage  which  will  pass  a  No. 

*  "Concrete,  Plain  and  Reinforced."  Taylor  and  Thompson. 


BUILDING  CONSTRUCTION.         (Ch.  IV) 


200  sieve  will  approximate  that  for  Portland  cement.  Fine  grind- 
ing is,  however,  not  as  essential  in  the  manufacture  of  natural  as 
in  Portland  cement,  as  the  amount  of  free  lime  present  is  much- 
less.  If  the  requirements  are  such  that  85  per  cent  or  more  must 
pass  a  No.  100  sieve,  and  70  per  cent  or  more  must  pass  a  No.  200 
sieve,  a  good  quality  of  natural  cement  should  result."* 

''Until  quite  recently  the  grinding  of  an  American  natural 
cement  was  rarely  carried  further  than  was  necessary  to  pass  95 
per  cent  of  the  material  through  a  50-mesh  sieve.  In  only  a  few 
cases  was  a  greater  fineness  demanded  than  85  per  cent  through  a 
lOO-mesh  sieve.  The  average  requirements,  then,  were  low,  and 
the  average  cement  just  about  passed  requirements. 

"Within  the  past  few  years  some  natural  cement  manufacturers 
have  realized  that  if  the  natural  cement  industry  is  to  be  main- 
tained in  the  face  of  competition  from  Portland  cement  the  product 
must  be  improved.  One  of  the  easiest  methods  of  doing  this  is  to 
increase  the  fineness  of  the  grinding.  This  has  the  effect  of  mak- 
ing the  cement  more  sound  and  of  increasing  its  sand-carrying 
capacity,  and  therefore  its  strength  when  tested  as  mortar. 

"There  are  differences  in  the  fineness  requirements  of '  several 
important  standard  specifications.  The  requirements  of  the  Ameri- 
can Society  for  Testing  Materials  (90  per  cent  through  lOO-mesh, 
70  per  cent  through  200-mesh)  are  high,  and  probably  cannot  be 
economically  attained  unless  modern  grinding  machinery  is  in  use 
at  the  mill.  With  tube  mills,  however,  this  fineness  can  be  readily 
reached,  and  the  tensile  strength  of  the  cement  is  greatly  im- 
proved."t 

166.  STRENGTH  TESTS. — For  Natural  Cements. — A  discus- 
sion of  the  various  tests  for  the  strength  of  different  kinds  of 
cements  is  taken  up  in  the  subdivision  of  this  chapter  devoted  to 
that  subject.  At  this  point,  however,  it  will  be  well  to  give  some 
of  the  standard  and  recent  usual  requirements  for  the  tensile 
strength  of  natural  cements.    (See  Articles  191,  197  and  208.) 

The  paragraph  relating  to  the  tensile  strength  of  natural  cements, 
in  the  Standard  Specifications  of  the  American  Society  Testing 
Materials,  is  as  follows  : 

The  minimum  requirements  for  tensile  strength  for  briquettes 


*  "Concrete,  and  Reinforced  Concrete  Construction."  Homer  A.  Reid. 
t "Cements,  Limes  iSfid  Plasters."    Edwin  C.  Eckel. 


NATURAL  CEMENTS,  153 

I  inch  square  in  cross-section  shall  be  within  the  following  limits, 
and  shall  show  no  retrogression  within  the  periods  specified. 

Age.                                       Neat  Cement.  Strengtfi. 

24  hours  in  moist  air  ,   50-100  lbs. 

7  days  (i  day  in  moist  air,  6  days  in  water)   100-200  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   200-300  lbs. 

I  part  Cement,  3  Parts  Standard  Sand. 

7  days  (i  day  in  moist  air,  6  days  in  water)   25-  75  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   75-150  lbs. 


The  tensile  strength  required  for  natural  cements  is  highly  vari- 
able in  specifications  for  even  large  and  important  works,  and  these 

variations  are  illustrated  in  the  following  table  :* 


TABLE  XL 
NATURAL  CEMENTS. 
Strength  Required  by  Various  Specifications. 


Neat 

I  :  I 

I  Day 

7  Days 

28  Days 

7  Days 

28  Days 

65  lbs. 
100  " 
60  " 
25-75*  " 

125  lbs. 
150  " 
150  " 
75-150*" 

Engineer  Corps,  U.  S.  A..  .  . 

SO-ioolbs. 

125  lbs. 
90  " 
100-200" 

200  lbs. 
200  *' 
200-300" 

*In  this  specification  the  mortar  mixture  is  i  cement,  3  sand. 


The  following  tests  belong  to  a  fuller  discussion  of  the  whole 
subject  of  strength  tests  of  cements  and  cement  mortars:  Com- 
pressive strength,  relation  of  compressive  to  tensile  strength,  trans- 
verse or  flectural  strength,  relation  of  flectural  fiber  stress  to  tensile 
stress,  adhesive  strength,  abrasive  or  wearing  resistance,  shearing 
strength  and  coefficient  of  elasticity. 

167.  SPECIAL  TESTS  OF  CEMENTS  AND  MORTARS.— 
The  most  important  tests  for  comparing  the  qualities  of  different 
cements  and  for  determining  their  practical  value  have  been  men- 
tioned or  discussed  in  the  preceding  articles.  There  are  certain 
other  tests,  which  may  be  merely  mentioned  here,  and  which  are 
sometimes  made  to  investigate  special  qualities  of  a  cement  or 
mortar,  or  for  scientific  research.  Such,  for  example,  are  the  tests 
which  are  made  for  porosity,  permeability,  yield  of  paste  and 


♦"Cements,  Limes  and  Plasters."    Edwin  C.  Eckel. 


154 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


mortar,  rise  of  temperature  while  setting,  homogeneity  (micro- 
scopical) and  decomposition. 

As  compared  with  the  standard  tests,  such  as  chemical  analysis, 
specific  gravity,  fineness,  activity  or  time  of  setting,  tensile  strength 
and  soundness  or  constancy  of  volume,  the  special  tests  above  men- 
tioned are  usually  of  minor  importance,  and  for  full  descriptions  of 
them  the  reader  is  referred  to  the  treatises  on  cement  testing. 

i68.  SPECIFICATIONS  FOR  NATURAL  CEMENTS.— 
Specifications  for  the  cement  for  any  particular  operation  are  based 
upon  the  architect's  or  engineer's  own  practice,  supplemented  by  a 
careful  study  of  the  model  specifications  of  other  recent  important 
works.  There  is  considerable  variation  in  the  requirements  on  vari- 
ous points,  and  it  is  useful  to  compare  these  dififerent  demands,  and 
thus  determine  the  average  of  good  and  safe  practice. 

Several  dififerent  sets  of  specifications  for  natural  cements  are 
given  in  Chapter  XIII,  "Specifications." 

One  excellent  set  is  given  here,  the  specifications  for  natural 
cement  based  upon  the  practice  of  Engineers  F.  W.  Taylor  and 
S.  E.  Thompson,  supplemented  by  their  careful  study  of  the  speci- 
fications of  the  following :  American  Society  for  Testing  Materials, 
American  Railway  Engineering  and  Maintenance-of-Way  Associa- 
tion, City  of  Philadelphia,  United  States  Army,  United  States  Navy, 
Massachusetts  Metropolitan  Commissions,  New  York  Rapid  Transit 
Commission,  and  others. 

1.  Packages. — Cement  shall  be  packed  in  strong  cloth  or  can- 
vas sacks. t  Each  package  shall  have  printed  upon  it  the  brand 
or  the  name  of  the  manufacturer.  Packages  received  in  broken  or 
damaged  condition  may  be  rejected  or  accepted  as  fractional  pack- 
ages. 

2.  Weight. — Three  bags  shall  constitute  a  barrel,  and  the  aver- 
age net  weight  of  the  cement  contained  in  one  bag  shall  not 
be  less  than  94  pounds,  or  282  pounds  net  per  barrel.  A  cement 
bag  may  be  assumed  to  weigh  one  pound.  The  weights  of  the 
separate  packages  shall  be  uniform. 

3.  Requirements.^ — Cement  failing  to  meet  the  seven-day  re- 
quirem'ents  may  be  held  awaiting  the  re&u-lt  of  the  twe-nty-eight- 
day  tests  before  rejection. 

*  Paragrapbs  designated  by  an  asterisk  are  quoted  from  the  Standard  Specifica'tions  of 
the  American  Society  for  Testing  Materials. 

tif  the  cement  is  to  be  stored  in  a  damp  place  or  near  the  sea,  it  must  be  packed 
in  well-made  wooden  barrels  lined  with  paper. 


NATURAL  CEMENTS.  155 

4.  Tests."^ — All  tests  shall  be  made  in  accordance  with  the 
methods  proposed  by  the  Committee  on  Uniform  Tests  of  Cement 
of  the  American  Society  of  Civil  Engineers,  presented  to  the  Society 
January  21,  1903,  and  amended  January  20,  1904,  with  all  subse- 
quent amendments  thereto. 

5.  Sampling. — Samples  shall  be  taken  at  random  from  sound 
packages,  and  the  cement  from  each  package  shall  be  tested  separ- 
ately. 

•6.'*'  The  acceptance  or  rejection  shall  be  based  on  the  following 
requirements : 

7.  Definition  of  Natural  Cement.'^ — This  term  shall  be  applied 
to  the  finely  pulverized  product  resulting  from  the  calcination  of  an 
argillaceous  limestone  at  a  temperature  only  sufficient  to  drive  off 
the  carbonic  acid  gas. 

8.  Specific  Gravity."^ — The  specific  gravity  of  the  cement  thor- 
oughly dried  at  100  degrees  Cent.  (212  degrees  Fahr.)  shall  be 
not  less  than  2.8. 

9.  Fineness."^ — It  shall  leave  by  weight  a  residue  of  not  more 
than  10  per  cent  on  the  No.  100,  and  30  per  cent  on  the  No.  200 
sieve. 

10.  Time  of  Setting."^ — It  shall  develop  initial  set  in  not  less 
than  ten  minutes,  and  hard  set  in  not  less  than  thirty  minutes, 
nor  more  than  three  hours. 

11.  Tensile  Strength. — Briquettes  one  inch  square  in  section 
shall  attain  at  least  the  following  tensile  strength  and  shall  show 
no  retrogression  within  the  periods  specified. 


NEAT  CEMENT. 

Age.  Strength.t 

24  hours  in  moist  air   50  lbs. 

7  days  (i  day  in  air,  6  days  in  water)   100  lbs. 

28  days  (i  day  in  air,  27  days  in  water)   200  lbs. 

ONE  PART  CEMENT,  THREE  PARTS  STANDARD  SAND. 
Age.  Strength.t 

7  days  (i  day  in  air,  6  days  in  water)   25  lbs. 

28  days  (i  day  in  air,  27  days  in  water)   75  lbs. 


12.    Constan'cy  of  Volume.'^ — Pats  of  neat  cement  about  3  inches 


*Paragraphs  designated  by  an  asterisk  are  quoted  from  the  Standard  Specifications 
of  the  American  Society  for  Testing  Materials. 

fThe  American  Society  for  Testing  Materials  gives  minimum  requirements  as  follows: 
Neat  Cement — 24  hrs.,  50-100  lb.;  7  days,  100-200  lb.;  28  days,  200-300  lb.;  1:3  mortar — 7 
days,  25-75  lb.;  28  days,  75-150  lb.;  the  exact  values  to  be  fixed  in  each  case  by  the 
consumer. 


156  BUILDING  CONSTRUCTION.  (Ch.  IV) 


in  diameter,  one-half  inch  thick  at  the  center,  and  tapering  to  a  thin 
edge,  shall  be  kept  in  moist  air  for  a  period  of  24  hours. 

{a)    A  pat  is  then  kept  in  air  at  normal  temperature.  . 

{h)  Another  pat  is  kept  in  water  maintained  as  near  70  degrees 
Fahr.  as  practicable. 

These  pats  are  observed  at  intervals  for  at  least  28  days,  and  to 
satisfactorily  pass  the  tests  should  remain  firm  and  hard  and  show 
no  signs  of  distortion,  checking,  cracking  or  disintegration. 

169.  MISCELLANEOUS  DATA  AND  MEMORANDA, 
PRINCIPALLY  ON  NATURAL  CEMENTS.— "Cement  is 
shipped  in  barrels  or  in  cotton  or  paper  bags.  The  usual  dimen- 
sions of  a  barrel  are :  length,  2  feet  4  inches ;  middle  diameter,  i 
foot  4^  inches ;  end  diameter,  i  foot  3^  inches. 

*The  bags  hold  50,  100  or  200  pounds. 

"A  barrel  weighs  about  as  follows : 

Rosendale,  N.  Y   300  lbs.  net. 

Rosendale,  Western   265  lbs.  net. 

Portland    375  lbs.  net. 

"A  barrel  of  Rosendale  cement  contains  about  3.40  cubic  feet  and 
will  make  from  3.70  to  3.75  cubic  feet  of  stiff  paste,  or  79  to  83 
pounds  will  make  about  one  cubic  foot  of  paste. 

"A  barrel  of  cement  measured  loosely  increases  considerably  in 
bulk.    The  following  results  were  obtained  by  measuring  in  quan- 


tities of  two  cubic  feet: 

I  bbl.  Norton's  Rosendale  gave   4.37  cu.  ft. 

I  bbl.  Anchor  Portland  gave   3.65  cu.  ft. 

I  bbl.  Sphinx  Portland  gave   3.71  cu.  ft. 

I  bbl.  Buckeye  Portland  gave   4.25  cu.  ft. 

**The  weight  of  cement  per  cubic  foot  is  as  follows : 

Portland,  English  and  German   77  to  90  lbs. 

Portland,  fine-ground  French   69  lbs. 

Portland,  American   92  to  95  lbs. 

Rosendale    49  to  56  lbs. 

Roman    54  lbs. 


''A  bushel  contains  1.2/^4  cubic  feet.  The  weight  of  a  bushel  can 
be  obtained  sufficiently  close  by  adding  25  per  cent  to  the  weight 
per  cubic  foot."* 


*  "Inspector's  Pocket  Book."    A.  T.  Byrne 


NATURAL  CEMENTS. 


157 


The  following  data  bearing  upon  the  above,  and  showing  slight 


variations,  are  taken  from  another  authority 

Portland  cement  weighs  per  barrel,  net   376  lbs. 

Portland  cement  weighs  per  bag,  net    94  lbs. 

Natural  cement  weighs  per  barrel,  net   282  lbs. 

Natural  cement  weighs  per  bag,  net   94  lbs. 

Cement  barrel  weighs  from  15  to  30  lbs.,  averaging  about   20  lbs. 

Portland  cement  is  assumed  in  standard  proportioning  to  weigh 

per   cubic    foot   100  lbs. 

Packed  Portland  cement,  as  in  barrels,  averages  per  cubic  foot 

about    115  lbs. 

Packed  Portland  cement,  based  on  3.5  cubic  feet  barrel  contents, 

weighs  per  cubic  foot   108^  lbs. 

Loose  Portland  cement  averages  per  cubic  foot  about   92  lbs. 

Volume  of  cement  barrel,  if  cement  is  assumed  to  weigh  100  lbs. 

per  cubic  foot   3.8  cu.  ft. 

American  Portland  cement  barrel  averages  between  heads  about..  3.5  cu.  ft. 

Foreign  Portland  cement  barrel  averages  between  heads  about...  3.25  cu.  ft. 

Natural  cement  barrel  averages  between  heads  about   3.75  cu.  ft. 


The  additional  data  in  this  article,  useful  in  estimates  of  cement 
work,  are  added  with  the  accompanying  explanatory  note  if 

"The  following  estimates  of  quantities  are  simply  approximate 
and  may  be  exceeded  or  not  attained,  according  to  the  local  cir- 
cumstances. While  most  of  them  are  the  results  of  actual  experi- 
ment under  practical  conditions,  the  writer  has  checked  but  few  of 
them  in  his  practice,  and  presents  them  as  being  correct  under  a 
single  set  of  conditions  only,  and  approximately  so  in  others.  For 
rough  estimates  they  will  answer  satisfactorily.  Each  engineer 
or  contractor  is  soon  able  to  estimate  his  own  quantities  under  the 
conditions  of  the  methods  he  adopts  better  than  he  can  from  any 
statements  of  average  results. 

Packing  and  Shipping  Cement. 

Cement  is  packed  in  barrels,  cloth  sacks  or  paper  bags,  as  ordered. 

•A  barrel  of  Portland  cement  weighs  about  400  pounds  gross,  and 
should  contain  380  pounds  net  of  cement. 

Portland  cement,  loose,  weighs  70  to  90  pounds  per  cubic  foot; 
packed,  about  no  pounds  per  cubic  foot. 

A  barrel  of  eastern  natural  hydraulic  cement  weighs  about  320 
pounds  gross  and  should  contain  300  pounds  net  of  cement. 

A  barrel  of  western  natural  hydraulic  cement  weighs  about  285 
pounds  gross  and  should  contain  265  pounds  net  of  cement. 


*  "Concrete,  Plain  and  Reinforced."  Taylor  and  Thompson, 
t  "Handbook  for  Cement  Users."    Charles  C.  Brown. 


158 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


Natural  hydraulic  cement,  loose,  weighs  about  50  to  57  pounds  per 
cubic  foot;  packed,  about  80  pounds  per  cubic  foot.    Weights  of  - 
cement  and  volumes  of  barrels  are  not  uniform.    Nearly  all  natural 
hydraulic  cement  is  sold  in  sacks. 

Slag  cement  weighs  about  350  pounds  gross,  or  330  pounds  net.  - 

Cloth  sacks  ordinarily  contain  one-third  of  a  barrel  of  natural 
hydraulic  cement.  The  standard  for  Portland  cement  is  one-fourth 
of  a  barrel.   Paper  sacks  contain  one-fourth  of  a  barrel. 

The  following  on  cement  packages  is  from  a  circular  issued  by  a 
firm  of  general  agents  for  cement : 

Four  paper  bags  or  four  cloth  bags  constitute  one  barrel  or  380 
pounds  of  Portland  cement.  The  paper  bags  are  charged  to  the  cus- 
tomer at  2^  cents  each  or  10  cents  per  barrel,  and  are  of  no  further 
value.  They  have  served  their  purpose  in  carrying  the  cement  to 
destination  and  have  given  you  service  that  is  worth  10  cents  per 
barrel.  The  cloth  bags  are  charged  at  10  cents  each  or  40  cents  per 
barrel,  and  are  worth  10  cents  each  or  40  cents  per  barrel  if  returned 
and  received,  freight  paid,  in  good  condition  at  the  mill. 

Here  has  been  the  misleading  part  to  the  consumer.  While  a  few 
paper  bags  are  liable  to  be  broken  in  transportation  with  a  corre- 
sponding loss  of  cement,  the  minimum  loss  of  cement  in  a  cloth  bag 
is  one  pound  to  the  sack  or  four  pounds  to  the  barrel.  This  amount 
remains  unshaken  from  the  bag.  We  have  seen  laborers  so  careless 
as  to  waste  3  per  cent  of  their  cement  in  this  manner.  A  paper  bag 
is  more  easily  handled — can  be  emptied  with  absolutely  no  loss  of 
cement.  It  takes  time  to  untie  a  cloth  bag  and  time  costs  money.  A 
paper  bag  can  be  cut  open  with  a  hoe  instantly. 

The  manufacturers  and  the  railroads  require  bags  returned  to  be 
freight  prepaid.  The  minimum  expense  of  such  transportation  from 
this  district  is  cents  per  barrel,  which  you  pay.  Use  paper  and 
save  it. 

The  table  on  page  159  from  The  Engineering  News  gives  an  idea 
of  the  variation  in  size  of  cement  barrels.  The  first  three  brands 
named  are  American  and  the  other  two  foreign  Portland  cements. 

A  carload  of  Portland  cement  usually  means  100  barrels  (40,000 
pounds)  ;  75  barrels  is  the  minimum  carload,  or  the  same  quantity 
by  weight  in  cloth  or  paper  bags. 

When  cement  is  ordered  in  cloth  sacks  the  sacks  are  charged  at 
cost,  viz. :  10  cents  each,  in  addition  to  the  cost  of  the  cement ;  but 
when  the  sacks  are  returned  to  the  works  in  good  condition,  freight 


NATURAL  CEMENTS.  r 
TABLE  XII. 

Table  Showing  Variations  in  Sizes  of  Cement  Barrels. 


(I) 

(2) 

(3) 

Difference 

Difference 

Portland 

Capacity 

Actual 

Volume 

between 

betweei\ 

.  cement 

of  bbl. 

contents. 

when 

(I) 

(2) 

brand 

cubic 

packed 

dumped 

and 

and 

feet 

measure 

loose 

(2) 

(3) 

Giant  

 3.5 

3-35 

4.17 

4% 

 3-45 

3.21 

3-75  • 

4" 

3-15 

4.05 

3" 

30'^ 

3. 16 

4.19 

2" 

33" 

 312 

3-03 

4.00 

3" 

33" 

prepaid,  10  cents  is  allowed  for  each,  with  a  deduction  of  2  cents  for 
wear  and  tear  in  some  cases. 

For  paper  bags  there  is  no  charge,  as  they  are  not  apt  to  be  re- 
turned. 

Empty  sacks  to  be  returned  should  be  safely  tied  in  bundles  of  ten 

or  fifty,  giving  the  name  of  the  sender." 

170.  THE  CHOICE  OF  CEMENTS,  AND  THE  SELECTION 
OF  BRANDS. — The  question  often  arises  as  to  whether  natural 
cement  or  Portland  cement  is  the  more  desirable  from  an  economic 
standpoint,  aside  from  considerations  of  strength  and  other  prop- 
erties. Local  conditions  generally  decide  the  question.  There  are 
some  general  rules  of  good  engineering  practice  which  have  beem 
formulated,  and  which  relate  to  the  classes  of  construction  for  which 
different  kinds  of  cement  and  lime  are  best  adapted.  These  classes 
have  already  been  mentioned  in  regard  to  the  uses  of  natural  cement 
mortar,  for  example,  under  that  heading.    (See  Article  164.) 

If  the  architect  or  engineer  decides  that  in  a  certain  structure 
either  natural  cement  or  Portland  cement  may  be  used,  the  relative 
cost  decides  the  choice,  and  the  cost  in  turn  depends  upon  the  pro- 
portions of  cement  and  sand  that  may  be  adopted  in  either  case. 

The  usual  proportions  for  natural  cement  mortar  are  i  :2,  that 
is,  one  part  of  cement  to  two  parts  of  sand,  by  volume,  while  in 
Portland  cement  mortar  the  sand  is,  up  to  a  certain  point,  only 
limited  by  practical  considerations,  such  as  the  handling  of  the 
cement  with  the  trowel,  and  goes  to  the  proportions  i  13  and  1 14. 

After  assuming  the  proportions  of  the  two  classes  of  mortar,  tbe 
relative  cost  is  governed  principally  by  the  nuantity  of  cement  in 
a  cubic  yard  of  mortar.    Tt  can  he  sho- -    '^-^t  Portland  cement 


i6o  BUILDING  COXSTRUCTION .  (Ch.  IV) 

mortar  made  of  one  'part  cement  to  four  parts  sand  is  equivalent 
in  cost  to  natural  cement  mortar  made  of  one  part  cement  to  two 
parts  sand,  when  Portland  cemert  delivered  on  the  job  costs  68  per 
cent  more  than  natural  cement,  or  when  the  former,  for  example, 
costs  $1.68  per  barrel,  and  the  latter  $i.oo  per  barrel. 

About  lo  per  cent  more  of  bricks  can  be  laid  in  a  given  time  with 
natural  cement  mortar  when  the  proportions  '  are  1:2  than  with 
Portland  cement  mortar  with  the  proportions,  for  example,  of  1 13 ; 
'Consequently  when  the  cost  of  Portland  and  natural  cement  is  the 
same,  the  natural  cement  produces  the  brickwork  for  less  money. 
It  has  been  estimated  that  in  some  cases  there  is  a  difference  of  30 
•cents  per  barrel  of  cement  corresponding  to  the  difference  in  the 
labor  of  laying  bricks ;  and  it  has  also  been  shown  that  Portland 
^cement  mortar  can  seldom  be  substituted  for  natural  cement  mortar 
without  an  increase  in  the  cost  of  the  work. 

In  regard  to  the  selection  of  any  particular  brand  from  a  number 
of  different  brands  of  the  sam.e  class  of  cements,  such  as  natural 
cements,  for  example,  the  architect  or  engineer  m.ust  be  guided  by 
experience,  by  the  history  and  reputation  of  that  special  brand,  or 
\>y  thorough  laboratory  tests.  Between  two  cements  which  are 
■''sound,"  and  which  set  properly,  the  choice  can  usually  be  made 
by  selecting  the  one  which  shows  the  greater  fineness  when  tested 
with  two  sieves,  as  already  described.  The  stronger  mortar  is 
usually  produced  by  the  finer  cement. 

The  cheapest  cement  is  not  always  the  most  economical.  Tables 
have  been  made  to  show  the  relative  economy  of  cements  offered 
by  bidders  at  different  prices,  especially  for  government  work.  The 
final  selection  is  made  after  careful  consideration  of  all  the  data 
referring  to  each  brand,  such  as  the  relative  tensile  strength  of  the 
mortars  of  certain  proportions  of  cement  to  sand,  the  products  of 
the  relative  strength  by  the  relative  cheapness,  the  soundness,  the 
volumes  of  the  barrels,  their  gross  net  weights,  the  percentages  of 
water  used  in  mixing  the  pastes  and  mortars,  the  timie  of  setting  of 
the  mortar,  and  the  strength  and  relative  economy  of  mortars  with 
sand  proportioned  to  the  price  of  each  cement.* 

'The  difficulties  which  are  encountered  in  the  attempt  to  discuss 
the  natural  cements  as  a  class,  laying  emphasis  upon  the  points  of 
resemblance  of  the  various  brands  and  disregarding  for  the  time 


*For  a  full  discussion  of  the  subjects  of  "The  Choice  of  Cement,"  and  "The  Selection 
of  the  Brand,"  see  "Concrete,  Plain  and  Reinforced,"  by  Taylor  and  Thompson. 


PORTLAND  CEMENTS. 


i6i 


their  many  points  of  difference,  are  greater  than  the  reader,  at  first 
sight,  may  imagine ;  for  few  engineers  reaUze  what  a  heterogeneous 
collection  of  products  is  included  under  the  well-known  name  of 
^natural  cement.'  The  cause  for  this  lack  of  knowledge  is  not  far 
to  seek.  Natural  cements  are  too  low  in  value  to  be  shipped,  under 
ordinary  circumstances,  far  from  their  point  of  production.  The 
natural  cement  made  at  any  given  locality  has  usually,  therefore, 
a  well-defined  market  area  within  which  it  is  well  known  and  sub- 
ject to  little  competition.  The  engineer  practicing  within  such  an 
area  naturally  forms  his  idea  of  natural  cements  in  general  from 
what  he  knows  of  the  brands  encountered  in  his  work,  and  as  all 
the  brands  from  one  cement-producing  locality  are  apt  to  resemble 
one  another  quite  closely,  he  is  likely  to  conclude  that  natural 
cements  are  quite  a  homogeneous  class,  with  many  points  of  resem- 
blance and  few  of  difference.  The  truth  is,  on  the  contrary,  that 
there  may  be  far  greater  differences  of  strength,  rate  of  set,  chemical 
composition,  etc.,  between  the  natural  cement  made  in  two  different 
localities  than  between  any  given  brand  of  natural  cement  and  a 
Portland  cement."*  See  also  Art.  182,  ''The  Choice  of  Portland 
Cement,  and  the  Selection  of  Brands." 

4.    PORTLAND  CEMENTS. 

171.  PLACE  OF  PORTLAND  CEMENT  IN  THE  CLASSI- 
FICATION.— The  classification  of  cementing  materials  has  already 
been  considered  under  that  heading  in  Article  157,  and  Portland 
cement  is  the  fourth  of  the  five  divisions  mentioned.  It  belongs  to 
the  group  of  hydraulic  cements,  and  is  perhaps  now  the  most  impor- 
tant of  the  cementing  materials. 

Having  considered  the  common  limes,  the  hydraulic  limes  and  the 
natural  cements,  the  Portland  cements  will  be  considered  in  the  fol- 
lowing articles. 

Reference  to  Table  IX,  in  Art.  157,  will  make  clear  the  position  of 
Portland  cement  in  the  classification,  and  show  the  comparison  of 
this  with  other  cementing  materials  in  the  typical  analyses  given. 

172.  DEFINITIONS  OF  PORTLAND  CEMENT.— The  fol- 
lowing is  the  definition  given  in  the  Standard  Specifications  of  the 
American  Society  for  Testing  Materials :  "This  term  applies  to 
the  finely  pulverized  product  resulting  from  the  calcination  to 
incipient  fusion  of  an  intimate  mixture  of  properly  proportioned 


*  "Cements,  Limes  and  Plasters."    Edwin  C.  Eckel. 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


argillaceous  and  calcareous  materials,  and  to  which  no  addition 
greater  than  3  per  cent  has  been  made  subsequent  to  calcination." 

The  term  ''argillaceous"  means  clayey,  and  ''calcareous"  means 
consisting  of  lime  or  calcium. 

The  definition  in  the  specifications  of  the  Engineer  Corps,  U.  S. 
Army,  1902,  is  as  follows : 

"By  a  Portland  cement  is  meant  the  product  obtained  from  the 
heating  or  calcining  up  to  incipient  fusion  of  intimate  mixtures, 
either  natural  or  artificial,  or  argillaceous  with  calcareous  substances, 
the  calcined  product  to  contain  at  least  1.7  times  as  much  of  lime,  by 
weight,  as  of  the  materials  which  give  the  lime  its  hydraulic  prop- 
erties, and  to  be  finely  pulverized  after  said  calcination,  and  there- 
after additions  or  substitutions  for  the  purpose  only  of  regulating 
certain  properties  of  technical  importance  to  be  allowable  to  not 
exceeding  2  per  cent  of  the  calcined  product." 

Another  definition  is: 

"Portland  cement  is  a  hydraulic  cementing  material  with  a  specific 
gravity  of  not  less  than  3.10  in  the  calcined  condition,  and  contain- 
ing not  less  than  1.7  parts  by  weight  of  lime  to  each  one  part  of 
silica  +  alumina  +  ii'on  oxide,  the  material  being  prepared  by  inti- 
mately grinding  the  raw  ingredients,  calcining  them  to  not  less  than 
clinkering  temperature,  and  then  reducing  to  proper  fineness." 

Mr.  Edwin  C.  Eckel,  of  the  U.  S.  Geological  Survey,  believes  that 
the  following  definition  will  be  found  more  satisfactory  than  those 
now  in  use  for  insertion  as  a  preliminary  requirement  in  cement 
specifications : 

"By  the  term  Portland  cement  is  to  be  understood  the  product 
obtained  by  finely  pulverizing  clinker  produced  by  burning  to  semi- 
fusion  an  intimate  artificial  mixture  of  finely  ground  calcareous  and 
argillaceous  materials,  this  mixture  consisting  approx-imately  of 
three  parts  of  lime  carbonate  (or  an  equivalent  amount  of  lime 
oxide)  to  one  part  of  silica,  alumina  and  iron  oxide.  The  ratio  of 
lime  (Ca  O)  in  the  finished  cement  to  the  silica,  alumina  and  iron 
oxide  together  shall  not  be  less  than  1.6  to  i,  or  more  than  2.3  to  i." 

The  question  of  the  definition  of  Portland  cement  for  specifica- 
tions is  an  important  one,  as  there  has  been  only  a  partial  and  not 
a  complete  agreement  as  to  what  is  to  be  understood  by  the  term. 
The  principal  difference  of  opinion  is  in  regard  to  the  question  of 
including  or  not  including  among  the  true  Portlands  those  cements 
made  by  burning  a  natural  rock  without  previous  mixing*  and  grind- 


PORTLAND  CEMENTS.  163 


ing,  and  any  definition  based  upon  such  criteria  would  exclude  some 
products  manufactured  in  France  and  Belgium  called  ''natural  Port- 
lands." Also,  in  regard  to  American-made  Portland  cements,  it  is 
considered  by  some  of  the  highest  authorities  a  serious  error  to  omit 
from  specifications  the  requirement  relating  to  the  pulverizing  or 
artificial  mixing  of  the  materials  prior  to  burning,  because  at  present 
there  are  no  true  Portland  cements  manufactured  in  America  from 
natural  mixtures  without  such  preliminary  pulverizing  and  artificial 
mixing. 

173.  THE  EARLY  HISTORY  AND  USE  OF  PORTLAND 
CEMENT. — Joseph  Aspdin,  a  brickmaker  of  Leeds,  England, 
invented  Portland  cement  and  took  out  a  patent  in  1824  on  the  manu- 
facture of  a  product  resulting  from  the  calcination  of  an  artificial 
mixture  of  pulverized  limestone  and  clay.  It  was  first  patented  as 
an  ''artificial  stone."  To  this  product  was  given  the  name  "Port- 
land," from  a  fancied,  though  really  slight  resemblance  of  the  cement 
after  it  has  set  to  the  noted  oolitic  limestone  from  the  Isle  of  Port- 
land, a  peninsula  on  the  south  coast  of  England,  in  Dorset,  near 
Weymouth.  This  stone,  well  known  to  all  English  architects  and 
engineers  as  "Portland  Stone,"  was  much  used  in  England  at  that 
time,  and  a  recent  prominent  example  of  its  use  is  the  London  West- 
minster Cathedral,  where  it  appears  in  bands  in  the  red  brickwork. 

It  was  not  until  about  twenty  years  after  the  discovery  by  Aspdin 
that  the  Portland  cement  industry  was  developed  to  any  great  extent, 
when  J.  B.  White  &  Sons,  in  Keiit,  England,  began  its  manufacture, 
and  when  a  little  later  Mr.  John  Grant,  an  eminent  English  engi- 
neer, made  irnportant  tests  and  used  the  cement  extensively  on  the 
London  drainage  works. 

In  France  the  first  manufactory  for  producing  Portland  cement 
was  established  at  Boulogne-sur-Mer  toward  the  middle  of  the  last 
century. 

In  Germany,  soon  after  the  first  production  of  the  cement  in 
France,  the  first  factories  were  built  for  the  production  of  the  Stettin 
brands.  Although  for  a  time  England  led  in^he  manufacture  of 
Portland  cement,  Germany  afterward  took  the  lead,  and  with  such 
success  that  for  a  while  it  was  the  foremost  country  in  the  amount 
produced,  in  1900  passing  all  other  countries. 

The  United  States  during  the  past  few  years  has  surpassed  all 
other  countries  in  the  manufacture  of  Portland  cement.    Mr.  David 


164 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


O.  Saylor,  of  Coplay,  Pa.,  in  the  Lehigh  Valley,  was  the  founder  of 
this  industry  in  America.  He  made  his  first  discoveries  in  1874  and 
1875,  built  his  first  factory  in  1878.  During  the  first  fifteen 
years  the  development  of  the  industry  was  exceedingly  slow,  but 
about  the  year  1890  it  took  a  new  start  and  since  then  has  been 
very  rapid. 

174.  THE  PRESENT  USE  OF  PORTLAND  CEMENT.— 
Good  Portland  cement  is  constantly  finding  wider  and  wider  fields 
of  application.  It  has  been  said  that  it  has  already  worked  a  revolu- 
tion in  engineering  and  architectural  construction  nearly  equal  in 
significance  to  that  following  upon  the  general  use  of  the  Bessemer 
and  open-hearth  processes  of  making  steel.  In  its  production  its 
quality  is  being  constantly  improved,  a  result  largely  due  to.  the 
excellent  systems  of  testing,  and  to  the  consequent  necessity  of 
employing  at  the  works  the  most  competent  scientific  supervision. 
It  is  now  made  on  a  gigantic  scale  in  the  United  States,  Germany, 
Belgium,  the  United  Kingdom  and  France. 

In  1890  only  335,500  barrels  of  Portland  cement  were  manu- 
factured in  the  United  States ;  but  since  that  time  the  development 
of  the  industry  has  been  so  rapid  that  in  1905  the  number  of  barrels 
reached  a  grand  total  of  35,246,812,  and  of  this  total  over  one-half 
was  produced  in  the  Lehigh  district  of  Pennsylvania  and  New  Jer- 
sey. In  1906  the  output  was  46,463,424  barrels,  valued  at  $52,- 
466,186,  and  the  estimated  output  for  1907  is  48,000,000  barrels. 
Existing  American  plants  have  now  (1908)  a  total  capacity  of  about 
60,000,000  barrels  a  year. 

The  wonderful  rapidity  of  the  development  of  the  manufacture 
of  Portland  cement,  and  the  increase  in  the  amount  of  this  cement 
produced  from  about  the  year  1880  to  the  present  time,  may  be  best 
understood  by  an  examination  of  the  tables  compiled  and  published 
by  the  government  and  by  the  most  recent  treatises  on  building 
materials  of  this  nature.  It  is  not  possible  in  this  brief  chapter  to 
insert  these  tables,  and  the  reader  is  referred  to  such  authoritative 
data  as,  for  example,  the  annual  reports  on  the  ''Mineral  Resources 
of  the  United  States,"  issued  by  the  United  States  Geological  Sur- 
vey, and  to  various  compilations  made  from  these  reports,  found  in 
recent  exhaustive  works  on  limes,  cements,  mortars  and  concretes. 
Such  are  the  tables  on  "Total  Production  of  Portland  Cement  in  the 
United  States  from  1870  to  Date,"  "Production  of  Portland  Cement 


PORTLAND  CEiMEXTS.  165 

in  the  United  States  for  the  Different  Years  by  States,"  "Distribution 
of  the  Manufacture  of  Portland  Cement  and  the  Development  in 
the  Various  Regions,"  ''Portland  Cement  Production  of  the  Lehigh 
District  of  Pennsylvania-New  Jersey,"  "Imports  of  Cement  into  the 
United  States  by  Years,  and  by  Countries,"  "Total  Consumption  of 
Natural  Cement,  Imported  Portland  Cement,  Domestic  Portland 
Cement  and  Puzzolan  Cement  in  tjie  United  States  in  Barrels,  and 
the  Annual  Percentages  of  Each  Class,"  "Consumption  of  Cement 
in  the  United  States  per  Capita  of  Population,"  "Exportation  of 
Cement  from  the  United  States,"  and  "Diagrams  Showing  Graphic- 
ally Changes  in  Percentages  of  Natural  Cement  and  Imported  and 
American  Portland  Cement  Used  Each  Year." 

175.  CHEMICAL  ANALYSIS  OF  PORTLAND  CEMENTS. 
— The  definitions  of  Portland  cement  have  already,  been  given 
in  Article  172.  A  Portland  cement  mixture,  when  ready  for 
burning,  should  contain  about  75  per  cent  of  lime  carbonate 
(CaCOg),  and  about  20  per  cent  of  silica  (SiOg),  alumina  (ALOg) 
and  iron  oxide  (FcgOg)  together,  the  remaining  5  per  cent  or  so 
containing  any  magnesia,  sulphur  and  alkalies  that  may  be  present. 
There  is  an  abundant  and  wide  distribution  in  nature  of  lime,  silica, 
alumina  and  iron,  which  occur  in  various  kinds  of  rocks  in  different 
forms. 

Mr.  Edwin  C.  Eckel  analyzes  the  various  raw  materials  available 
for  use  in  Portland  cement  manufacture  as  follows :  He  states  that 
as  to  composition,  they  may  be  (a)  purely  calcareous,  (b)  a  mixture 


TABLE  XIII.* 
Character  of  Portland  Cement  Materials. 


Natural 

Artificial 

Hard 

Soft 

Unconsolidated 

Unconsolidated 

Calcareous 
(CaCOg  over  75%) 

Pure  hard 
limestone 

Pure  soft 
limestone  or 
pure.,  chalk 

Pure  marl 

Alkali  waste 

Argillo-calcareous 
(CaCOg  40  to  75%) 

Hard  clayey  • 
limestone 
(cement  rock) 

Soft  limestone 
or  clayey 
chalk 

Clayey  marl 

Blast-furnace 
slag 

Argillaceous 

(CaCOg  less  than  40%  ) 

Slate 

Shale 

Clay 

*  "Cements,  Limee  and  Plasters."    Edwin  C.  Eckel. 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


of  calcareous  and  argillaceous  elements,  or  (c)  almost  purely  argil- 
laceous; as  to  physical  character  they  may  be  (a)  hard  and  massive, 
like  the  hard  limestones  and  slates,  (b)  soft,  like  the  chalks  and 
shales,  or  (c)  granular  or  unconsolidated,  like  the  marls,  clays,  alkali 
waste  and  granulated  slag.  As  to  origin,  they  may  be  (a)  natural, 
like  limestones,  marls,  slates,  clays,  etc.,  or  (b)  artificial,  like  alkali 
waste  and  furnace  slag. 

The  same  writer  in  various  valuable  papers  published  at  different 
times  has  grouped,  under  six  heads,  the  various  combinations  of  raw 
materials  at  present  used  in  the  United  States  in  the  manufacture  of 
Portland  cement: 

(1)  Argillaceous  hard  limestone  (cement  rock)  and  pure  lime- 
stone. 

(2)  Pure  hard  limestone  and  clay  (or  shale 

(3)  Soft  (chalky)  limestone  and  clay  (or  shale). 

(4)  Marl  and  clay  (or  shale). 

(5) ^  Alkali  waste  and  clay. 

(6)  Slag  and  pure  limestone. 

The  materials  vary  with  the  locality.  In  the  Lehigh  district  the 
chief  raw  materials  used  are  cement  rock  and  limestone,  and  the 
Virginias,  Alabama,  Colorado  and  Utah  have  similar  formations ;  in 
the  New  York  State  Eastern  cement  region  and  in  California  and 
occasionally  in  the  Central  States,  limestone  and  clay;  in  Western 
New  York  and  in  the  Middle  West,  marl  and  clay;  and  in  the 
States  bordering  the  Mississippi  River  on  the  west  and  in  Texas 
and  Arkansas,  chalk  and  clay.  Slag  and  limestone  are  little  used  in 
the  United  States,  although  extensively  employed  in  Europe. 

In  Germany  the  Alsen  and  Stettin  brands  are  made  from  chalk 
and  clay;  the  Mannheimer  and  Dyckerhoff  brands  from  limestone 
and  clay ;  while  the  Hannover  and  Germania  manufactories  use  marl 
and  clay. 

In  England  chalk  and  clay  principally  are  the  raw  materials. 

In  Belgium  chalk  and  clay  are  used  by  the  manufacturers,  and  a 
natural  rock  also  is  used  for  the  production  of  a  Portland  cement. 

In  France,  marl  and  clay,  and  chalk  and  clay,  constitute  the  prin- 
cipal constituents  for  true  Portland  cements. 

The  ordinary  composition  of  a  good  Portland  cement  should 


PORTLAND  CEMENTS.  167 

approximate  the  following  limits  given  by  H.  Le  Chatelier,  the  emi- 
nent  authority  :  p^^^^^^ 

Silica    21  to  24 

Alumina    6  to  8 

Iron  Oxide   2  to  4 

Lime  ,   60  to  65 

Magnesia   0.5  to  2 

Sulphuric  Acid  0.5  to  1.5 

Carbonic  Acid  and  Water   i  to  3 


For  a  comparison  of  the  chemical  composition  of  the  different 
kinds  of  cements  and  of  limes,  see  Table  IX,  "Typical  Analyses  of 
Cements,"  in  Article  157,  on  the  ^'Classification  of  Cementing 
Materials."*  ^ 

There  is  a  large  mass  of  literature  on  the  subject  of  "The  Con- 
stitution of  Portland  Cement,"  as  it  has  grown  rapidly  in  importance 
during  recent  years. f 

176.  THE  MANUFACTURE  OF  PORTLAND  CEMENTS. 
— The  process  of  manufacturing  Portland  cement  from  rock,  or  rock 
and  clay  mixtures,  consists  essentially  of  (a)  crushing  the  materials, 
either  separately  or  after  mixing  them,  (b)  drying,  (c)  grinding, 
(d)  calcining,  (e)  cooling,  (f)  grinding  to  powder  and  (g)  packing. 

There  is  greater  variety  in  the  methods  employed  for  producing 
Portland  cement  than  for  natural  cement.  Portland  cement  clinker 
is  not  as  readily  powdered  as  the  burnt  natural  cement  rock,  but 
grinding  machinery  similar  to  that  used  in  Portland  cement  plants 
is  now  used  in  the  newer  natural  cement  mills. 

The  methods  of  mixing  the  materials  in  preparation  for  their 
introduction  into  the  kilns  has  led  to  a  classification  of  the  processes 
into  A,  the  dry  process,  and  B,  the  wet  process.  In  these  processes 
either  i.  Stationary  kilns,  or  2,  Rotary  kilns,  are  used.  The  stationary 
kilns  may  be  either  (i)  Intermittent  kilns,  or  (2)  Continuous  kilns. 

A. — The  dry  process  was  first  used  in  Germany,  when  limestone 


*  For  a  very  interesting  and  complete  table  giving  the  analyses  of  80  of  the  most 
prominent  American  Portland  Cements,  see  the  article  on  the  "Composition  of  American 
Portland  Cements."    Table  221,  in  "Cements,  Limes  and  Plasters,"  by  Edwin  C.  Eckel. 

+  Bonnami.  H.  Fabrication  et  controle  des  chaux  hydrauliques  et  des  ciments.  8vo. 
276  pp.    Paris,  1888. 

Le  Chatelier,  H.  Tests  of  hydraulic  materials.  Trans.  Arrffcr.  Inst.  Mining  Engineers, 
vol    22,   pp.   3-52.  1894- 

Newberry,  S.  B.  and  W.  B.  The  constitution  of  hydraulic  cements.  Journ.  Soc. 
Chem.  Industry,  vol.   16,  pp.  887-894.  1897. 

Richardson,  C.  The  constitution  of  Portland  cement.  Cement,  vols.  3,  4,  5. 
1903-1905. 

Richardson,  C.  The  constitution  nf  Portland  cement  from  a  physico-chemical  stand- 
point.    i2mo,     20  pp.    Long  Island  City,  N.  Y.,  1904. 

Richardson,  C.  The  setting  or  hydration  of  Portland  cement.  Engineering  News,  vol. 
53.  PP-  84-85.     Jan.  26,  1905. 


i68 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


was  substituted  for  the  chalk  of  England.  In  the  early  days  of  the 
industry  all  cement  was  burned  in  stationary  kilns.  They  are  still 
occasionally  used  in  the  United  States,  and  to  a  large  extent  in 
Germany  and  France.  They  are  of  two  general  types,  intermit- 
tent kilns,  which  are  completely  charged  and  then  burned,  and 
continuous  kilns,  in  which  there  is  a  continuous  maintenance  of  the 
fire,  and  in  which  the  raw  materials  are  dried  and  heated  by  the 
exhaust  heat  before  they  are  burned. 

There  has  been  a  universal  introduction  of  rotary  kilns  into  new 
cement  plants,  and  a  gradual  substitution  of  them  in  the  older  mills 
for  the  stationary  kilns.  The  typical  method  for  the  manufacture 
of  Portland  cement  may  be  considered  to  be  the  dry  process  with 
rotary^kilns. 

In  the  dry  process  the  ingredients  are  ground  and  mixed  in  a  dry 
state.  For  stationary  kilns  the  mixed  materials  are  moistened  with 
enough  water  to  make  plastic  bricks,  afterwards  dried.  For  rotary 
kilns  there  is  no  addition  of  water,  and  the  mixture  of  dry  materials 
passes,  after  grinding,  directly  into  the  kiln.  The  following  is  a 
brief  description  of  a  rotary  kiln  used  for  calcining  dry  materials 
and  of  the  process  of  manufacture  of  the  cement  from  the  time  of 
entering  the  kiln  to  the  packing  ready  for  shipment 

*'The  rotary  kiln  is  a  steel  cylinder,  varying  in  length  from  40  to 
150  feet  and  from  4^  to  9  feet  in  diameter,  lined  with  from  6  to  12 
inches  of  fire-brick,  with  its  axis  inclined  8  or  10  degrees  to  the  hori- 
zontal, and  arranged  to  rotate  at  a  speed  averaging  about  one  turn 
per  minute.  The  raw  materials  are  introduced  at  the  upper  end  in 
form  of  powder,  and  in  passing  through  are  calcined  to  a  clinker, 
which  leaves  the  kiln  at  the  lower  end  in  small  balls,  ranging  from 
to  inches  in  diameter.  Finely  pulverized  gas-slack  coal  is 
generally  used  for  fuel,  although  both  gas  and  oil  have  been  em- 
ployed, but  with  poorer  results.  The  coal  is  blown  into  the  lower  end 
of  the  kiln,  and  instantly  ignites,  forming  a  flame  reaching  from  15 
to  25  feet  into  the  kiln,  and  producing  a  temperature  of  from  2,600 
to  3,000  degrees  Fahrenheit.  The  coal  is  pulverized  in  the  same 
manner,  and  to  about  the  same  degree  of  fineness  as  the  raw  mate- 
rials. The  temperature  and  time  of  burning  vary  with  the  nature 
of  the  raw  materials. 

''The  clinker  as  it  leaves  the  kiln  is  sprayed  with  a  small  stream 
of  water,  which  cools  and  makes  it  more  easy  to  pulverize.    It  then 

*  "Concrete,  and  Reinforced  Concrete  Construction."    Homer  A.  Reid. 


PORTLAND  CEMENTS. 


169 


passes  through  coolers,  which  reduce  it  to  a  normal  temperature. 
From  the  coolers  the  clinkers  pass  to  the  pulverizing  and  grinding 
machines,  which  are  similar  to  those  for  reducing  the  raw  material. 
The  finished  cement  from  the  grinding  machines  is  conveyed  to  the 
stock  house,  often  being  stored  for  a  time  tq  give  it  a  chance  to 
'season'  somewhat.  It  is  then  packed  in  bags  or  barrels  for  ship- 
ment." ♦ 

B. — The  wet  process  is  employed  with  soft  or  wet  materials,  such 
as  chalk  and  clay,  and  marl  and  clay,  and  may  be  used  with  either 
the  stationary  or  rotary  kilns.  The  latter  was  first  used  in  England 
on  wet  materials.  In  the  United  States  it  is  usually  only  employed 
by  the  mills  in  which  the  raw  material  used  is  marl,  although  it  is 
adapted  to  chalk  or  other  materials,  which  are  easily  reduced  when 
in  a  wet  condition. 

The  carbonate  of  lime  and  the  clay  are  mixed  in  a  vat  or  wash- 
mill  with  a  large  excess  of  water,  the  lumps  are  broken  up  by  agita- 
tors which  reduce  the  particles  to  so  fine  a  condition  that  the  water 
holds  them  in  suspension  and  they  flow  off  over  the  top  of  the  vat. 
The  material  then  settles -in  another  receptacle,  the  water  is  drawn 
off,  and  the  ''slurry"  becomes  hard  enough  to  handle  in  barrows 
and  then  form  into  bricks  to  be  dried.  This  is  the  process  for  the 
stationary  kilns,  in  which  these  bricks  are  calcined. 

Regarding  the  wet  process  with  rotary  kilns,  it  may  be  said  that 
these  kilns,  almost  universally  adopted  in  the  United  States  for 
calcining  dry  materials,  have  more  recently  had  their  use  extended 
to  handling  the  slurry,  of  a  thick  creamy  consistency,  and  drying  it 
with  the  same  flame  used  for  calcination.  The  wet  slurry  is  pumped 
into  the  upper  ends  of  the  rotary  kilns,  which  are  usually  somewhat 
longer  than  those  employed  in  the  dry  process. 

After  calcination  the  treatment  is  similar  to  that  in  mills  where 
dry  materials  are  used. 

Silica-Portland  Cement,  or  Sand-Portland  Cement. — This  is  a 
mixture  of  true  Portland  cement  and  siliceous  sand  ground  together 
into  an  impalpable  powder  in  a  tube-mill. 

A  mixture  of  equal  parts  of  sand  and  cement  thus  ground  together 
possesses  about  the  same  strength  as  ordinary  Portland  cement  alone. 

'*A  mixture  of  silica-cement,  i  part  cement  and  i  part  sand,  with 
3  parts  unground  sand,  has  the  same  composition  as  i  part  cement 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


and  7  parts  sand ;  but  possessing  the  strength  of  a  mixture  of  I  part 
cement  and  3  parts  sand.* 

The  siHca-cement  process  was  first  introduced  into  Denmark  and 
has  the  special  advantage  of  making  mortar  that  is  impermeable  to 
moisture  and  able  to  ^resist  the  action  of  the  elements. 

Eight  thousand  barrels  of  silica-cement  were  used  in  the  founda- 
tion of  the  Cathedral  of  St.  John  the  Divine,  New  York  City. 

177.  THE  USES  OF  PORTLAND  CEMENTS.— Portland 
cement  is  by  far  the  most  useful  and  valuable  of  all  the  cements. 
If  quick  setting  is  not  necessary,  but  great  ultimate  strength  required, 
this  cement  should  be  adopted.  It  is  used  in  almost  all  kinds  of 
masonry  construction,  but  chiefly  in  foundations  in  wet  places,  in 
subaqueous  work  of  all  kinds,  for  important  structures  where  great 
strength  is  required,  and  in  plain  and  reinforced  concrete  work.  It 
is  also  used  in  the  more  exposed  parts  of  ordinary  structures,  such  as 
the  copings  of  walls  and  the  tops  of  chimneys,  for  protecting  the 
outer  faces  of  walls  and  buildings  from  the  weather,  for  thin  walls 
where  extra  strength  is  required,  for  pointing  and  filleting,  and  for 
arches,  piers  and  other  important  parts  of  buildings  and  engineering 
works. 

Portland  cement,  as  it  has  been  said  elsewhere,  has  worked  a  revo- 
lution in  engineering  construction,  and  is  still  finding  wider  and  wider 
fields  of  application. 

In  discussing  the  choice  of  cements,  Messrs.  Taylor  and  Thompson 
statef  that  ''Portland  cement  should  be  used  in  concrete  and  mortar 
for  structures  subjected  to  severe  or  repeated  stresses;  for  structures 
requiring  strength  at  short  periods  of  time ;  for  concrete  building 
construction ;  for  work  laid  under  water  or  with  which  water  will 
come  in  contact  immediately  after  placing;  for  thin  walls  subjected 
to  water  pressure ;  for  masonry  exposed  to  wear  or  to  the  elements ; 
and  for  all  other  purposes  where  its  cost  will  be  less  lhan  that  of 
natural  cement  concrete,  or  mortar  of  similar  quality." 

Mr.  Homer  A.  Reid,  in  discussing^  the  properties  of  cement  and 
methods  of  testing,  states  that  ''Portland  cement  is  used  for  rein- 
forced concrete  construction  almost  to  the  exclusion  of  other  cements. 
Its  great  strength,  uniform  composition  and  the  regularity  of  its 
properties  eminently  fit  it  for  this  class  of  work." 


*  Addison  H.  Clark,  in  "Architects'  Handbook  of  Cements." 
t  "Concrete,  Plain  and  Reinforced."  Taylor  and  Thompson. 
^"Concrete,  and  Reinforced  Concrete  Construction."    Homer  A.  Reid. 


PORTLAND  CEMENTS. 


171 


Professor  C.  J.  Fiebeger  in  writing  of  limes  and  cement  mortars* 
says,  with  reference  to  engineering  works  in  particular,  ''Portland 
cement  mortar  is  employed  in  structures  in  which  great  strength 
is  required,  as  in  masonry  dams  and  masonry  arched  bridges ;  where 
the  surface  is  exposed  to  mechanical  wear,  attrition,  or  blows,  as  in 
sidewalks  and  fortifications ;  and  takes  the  place  of  natural  cement 
whenever  the  cost  of  the  work  is  not  thereby  increased." 

''The  cement  should  be  suited  to  the  work  in  which  it  is  to  be 
used.  This  will  decide  whether  natural,  hydraulic,  puzzolan  or  Port- 
land cement  shall  be  used,  and  the  grade  of  the  latter.  Economy 
should  be  one  of  the  elements  considered  and  may  turn  the  decision 
to  a  natural  cement  in  one  locality,  while  some  grade  of  Portland 
cement  would  be  used  in  another.  For  external  work  the  conditions 
of  variation  in  temperature,  drainage,  possibility  of  shocks,  blows 
and  abrasions,  and  appearance  determine  the  grade  of  Portland 
cement  to  be  used."t 

178.  CHARACTERISTIC  PROPERTIES  AND  REQUIRE- 
MENTS OF  PORTLAND  CEMENT.— 

Packages,  Field  Inspection  and  Sampling. — The  statement  made 
in  regard  to  these  particulars  under  natural  cement  in  Article  165 
apply  also  to  Portland  cement. 

Color. — As  was  said  under  this  subdivision  for  natural  cement, 
the  color  of  a  cement  is  no  criterion  of  its  quality.  It 'may  show, 
however,  too  large  an  amount  of  some  ingredient,  and  for  some 
particular  brand,  differences  in  shade  may  be  an  index  of  variations 
in  the  composition  of  the  rock  from  which  the  cement  was  made, 
or  of  the  degree  of  burning.  "Portland  cement  should  be  a  dull 
gray.  Bluish-gray  probably  indicates  an  excess  of  lime ;  dark  green, 
a  high  percentage  of  iron ;  brown,  an  excess  of  clay ;  and  a  yellowish, 
shade  indicates  overburning.":|: 

"The  chemical  composition  of  Portland  cement  made  by  different 
processes  is  so  uniform  that  the  color  of  different  brands  varies  less 
than  that  of  natural  cements. 

"The  color  of  Portland  cement  is  described  as  cold  blue  gray. 
The  dark  color  of  the  coarser  particles  of  a  Portland  cement  left  as 
residue  on  a  screen  is  due  simply  to  the  fact  that  cement  clinker  is 

*  "Civil  Engineering."    C.  J.  Fiebeger. 

t  "Handbook  for  Cement  Users."  Charles  C.  Brown.  Published  by  Municipal  Engi- 
neering Company,   Indianapolis  and  New  York. 

$  "Concrete,  and  Reinforced  Concrete  Construction."    Homer  A.  Reid. 


172 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


black,  and  pieces  which  are  not  finely  ground  retain  the  color  of 
the  clinker."'^ 

Mr.  David  B.  Butler  saysf  that  a  brownish  color  denotes  insuffi-  ■ 
cient  calcination  or  the  use  of  unsuitable  clay  or  possibly  excess 
of  clay. 

The  origin  of  the  name  "Portland  Cement,"  from  a  fancied 
resemblance  in  its  color  to  the  English  Portland  stone,  has  already 
been  referred  to. 

Mr.  Austin  T.  Byrne  saysj  that  the  color  of  Portland  cement 
should  be  a  dull  bluish  or  greenish  gray,  caused  by  the  dark  ferru- 
ginous lime  and  the  intensely  green  manganese  salts ;  that  any 
variation  from  its  color  indicates  the  presence  of  some  impurity; 
and  that  blue  indicates  an  excess  of  lime,  dark  green  a  large  per- 
centage of  iron,  brown  an  excess  of  clay  and  a  yellowish  shade  an 
underburned  material. 

Weight. — The  quality  of  a  cement  is  not  indicated  by  the  weight 
alone.  If  weight  is  considered  it  must  be  taken  in  conjunction  with 
fineness.  Either  a  fine  grinding  or  an  underburning  may  cause 
a  light  weight.  Until  recently  specifications  required  a  standard 
weight  per  struck  bushel  or  per  cubic  foot,  the  idea  being  that,  other 
conditions  being  equal,  a  cement  thoroughly  burned  is  heavier  than 
one  underburned.  But  when  it  was  discovered  that  the  degree  of 
fineness,  much  more  than  any  difiference  in  calcination,  affects  the 
weight,  the  weight  requirements  were  omitted,  and  tests  for  specific 
gravity  substituted. 

Experiments  have  shown  that  the  weight  of  a  cement  decreases 
with  age. 

According  to  the  specifications  of  the  American  Society  for  Test- 
ing Materials,  Portland  cement  should  be  packed  in  bags  of  94 
pounds  net  weight,  four  of  which  make  a  barrel  of  376  pounds  net. 
Some  other  specifications  require  a  barrel  of  375  pounds  net.  For 
convenience  in  ordinary  calculations  it  is  often  assumed  that  a  barrel 
of  Portland  cement  weighs  400  pounds  gross  or  380  pounds  net. 

In  standard  proportioning  it  is  assumed  to  weigh  100  pounds  per 
cubic  foot. 

Packed  in  barrels  it  averages  115  pounds  per  cubic  foot. 
Packed  Portland  cement  based  on  3.5  cubic  feet  barrel  contents 
weighs  1085^  pounds  per  cubic  foot. 

*  "Concrete,  Plain  and  Reinforced."    Taylor  and  Thompson. 

t  "Portland  Cement."    David  B.  Bvtler. 

t  "Inspector's  Pocket  Book."    Austin  T.  Byrne. 


PORTLAND  CEMENTS, 


1/3 


Loose  Portland  cement  averages  about  92  pounds  per  cubic  foot. 

Specific  Gravity. — Under  this  heading,  in  discussing  the  properties 
of  natural  cements,  the  significance  in  general  of  the  specific  gravity 
tests  for  cement  was  explained. 

With  Portland  cements  the  specific  gravity  is  of  little  importance 
in  itself,  although  it  will  serve  to  detect  underburned  or  adulterated 
cement.  A  well-dried  sample  of  Portland  cement  will  have  a  specific 
gravity  which  is  seldom  lower  than  3.10,  while  a  natural  cement, 
or  a  slag  cement,  or  a  Portland  cement  adulterated  with  slag  will 
have  a  specific  gravity  which  is  rarely  higher  than  3.00.  It  must  be 
admitted,  however,  that  there  are  a  few  American  natural  cements 
showing  a  specific  gravity  of  3.00,  and  reaching  as  high  as  3.2. 

The  standard  specifications  of  the  American  Society  for  Testing 
Materials  require  that  the  specific  gravity  of  Portland  cement,  thor- 
oughly dried  at  100°  Cent.  (212°  Fahr.),  shall  be  not  less  than  3.10. 

Mr.  Homer  A.  Reid  says*  ''the  specific  gravity  of  Portland  cement 
varies  from  3.00  to  3.25,  but  for  the  higher  grades  of  American 
cements  it  is  usually  found  to  be  between  3.10  and  3.25." 

Activity,  or  Time  of  Setting. — A  brief  general  description  of  the 
use  and  significance  of  the  tests  for  this  property  has  already  been 
given  under  natural  cements. 

The  specifications  of  the  American  Society  for  Testing  Materials 
require  that  Portland  cement  shall  develop  "initial  set"  in  not  less 
than  thirty  minutes,  but  must  develop  "hard  set"  in  not  less  than 
one  hour  nor  in  not  more  than  ten  hours. 

Portland  cements  are  generally  much  slower  in  setting  than 
natural  cements.  There  are,  however,  as  was  mentioned  under 
natural  cements,  a  few  of  the  latter  which  are  slow-setting. 

Soundness,  or  Constancy  of  Volume. — The  purpose  and  general 
description  of  the  test  was  described  under  natural  cements,  and 
those  phenomena  common  to  both  natural  and  Portland  cements 
were  mentioned. 

The  soundness  tests  are  of  greater  importance  than  any  other, 
and  are  often  the  only  ones  necessary.  An  unsound  cement  is  likely 
to  go  to  pieces  on  the  work. 

The  following  are  the  requirements  in  the  specifications  of  the 
American  Society  for  Testing  Materials  for  Soundness  or  Constancy 
of  Volume  of  Portland  Cement : 

Pats  of  neat  cement  about  three  inches  in  diameter,  one-half  inch 


*  "Concrete  and  Reinforced  Concrete  Construction."    Homer  A.  Reid. 


174  BUILDING  CONSTRUCTION.  (Ch.  IV) 


thick  at  the  center,  and  tapering  to  a  thin  edge,  shall  be  kept  in  moist 
air  for  a  period  of  twenty-four  hours. 

(a)  A  pat  is  then  kept  in  air  at  normal  temperature,  and  observed 
at  intervals  for  at  least  28  days. 

(b)  Another  pat  is  kept  in  water  maintained  as  near  70°  Fahr.  as 
practicable,  and  observed  at  intervals  for  at  least  28  days. 

(c)  A  third  pat  is  exposed  in  any  convenient  way  in  an  atmos- 
phere of  steam,  above  boiling  water,  in  a  loosely  closed  vessel  for 
five  hours. 

These  pats  to  satisfactorily  pass  the  requirements  shall  remain 
firm  and  hard  and  show  no  signs  of  distortion,  checking,  cracking  or 
disintegration. 

Engineers  are  pretty  well  agreed  that  it  is  safe  to  adopt  the  fol- 
lowing conclusion:  ''If  a  Portland  cement  passes  the  hot  test  it 
may  be  used  immediately  with  reasonable  certainty  of  its  ultimate 
soundness.  If  it  fails  to  pass,  it  should  be  regarded  with  sus- 
picion and  thoroughly  tested." 

The  following  are  useful  and  simple  directions  for  soundness  test- 
ing for  small  purchasers  of  Portland  cement :  "Take  about  ^  pound, 
or  one  cupful,  of  Portland  cement  and  mix  by  kneading  minutes 
with  sufficient  water  to  form  a  paste  of  a  consistency  like  putty. 
Press  portions  of  the  paste  onto  3  pieces  of  window  glass  4  inches 
square,  so  as  to  make  3  pats  each  about  3  inches  in  diameter  and 
3^  an  inch  thick  at  center,  tapering  to  a  thin  edge,  and  place  in  moist 
air  for  24  hours.  Then  keep  one  pat  in  air  at  moderate  temperature 
(about  60°  or  70°  Fahr.)  for  28  days,  keep  second  pat  in  water  for 
28  days,  and  place  third  pat  in  loosely  closed  vessel  over  boiling 
water  and  keep  there  for  five  hours.  Reject  cement  if  any  pats  show 
radial  cracks  or  curl  or  crumble.  The  air  pat  should  not  change 
color.  Portland  cement  may  be  accepted  on  the  steam  test  alone  if 
time  is  limited.  Natural  cements  should  be  subjected  to  water  and 
air  but  not  to  steam."* 

Fineness. — The  general  significance  of  the  fineness  tests  for  all 
cements  was  explained  under  this  subdivision  in  treating  of  natural 
cements. 

The  following  are  the  requirements  for  the  fineness  of  a  Portland 
cement,  taken  from  the  standard  specifications  of  the  American 
Society  for  Testing  Materials   "It  shall  have  by  weight  a  residue  of 

*  "Concrete,  Plain  and  Reinforced.".   Taylor  and  Thompson, 


PORTLAND  CEMENTS. 


not  more  than  8  per  cent  on  the  No.  loo,  and  not  more  than  25  per 
cent  on  the  No.  200  sieve." 

The  fineness  requirements  of  some  other  specifications  for  Port- 
land cement  used  in  important  works  are  as  follows : 

(1)  Rapid  Transit  Subway,  New  York  City,  1900-1901 : 

''Ninety-eight  per  cent  shall  pass  a  No.  50  sieve  and  90 
per  cent  a  No.  100  sieve." 

(2)  New  York  State  Canals,  1896: 

"Portland  cement  must  be  of  such  fineness  that  95  per  cent 
of  the  cement  will  pass  through  a  sieve  of  2,500  meshes 
to  the  square  inch,  and  90  per  cent  through  a  sieve  of 
10,000  meshes  per  square  inch." 

(3)  Department  of  Bridges,  New  York  City,  1901 : 

"Cement  must  be  ground  so  fine  that  90  per  cent  of  it  will 
pass  through  a  sieve  of  10,000  meshes  per  square  inch." 

(4)  Engineer  Corps,  U.  S.  Army,  1902: 

"Ninety-two  per  cent  of  the  cement  must  pass  through  a 
sieve  made  of  No.  40  wire,  Stubbs'  gauge,  having  10,000 
openings  per  square  inch." 

(5)  U.  S.  Reclamation  Service,  1904: 

"Ninety-five  per  cent  by  weight  must  pass  through  a  No. 
100  sieve  having  10,000  meshes  per  square  inch,  the  wire 
to  be  No.  40  Stubbs'  wire  gauge ;  and  75  per  cent  by 
weight  must  pass  through  a  No.  200  sieve  having  40,000 
meshes  per  square  inch,  the  wire  to  be  No.  48  Stubbs'  wire 
gauge." 

(6)  Canadian  Society  of  Civil  Engineers,  1903 : 

"The  cement  shall  be  ground  so  fine  that  the  residue  on  a 
sieve  of  10,000  meshes  to  the  square  inch  shall  not  exceed 
10  per  cent  of  the  whole  by  weight,  and  the  whole  of  the 
cement  shall  pass  a  sieve  of  2,500  meshes  to  the  square 
inch." 

The  following  is  a  simple  test  for  the  fineness  of  a  cement :  "Sift 

5  ounces  of  dry  cement  containing  no  lumps  through  a  sieve  about 

6  to  8  inches  diameter  with  100  meshes  per  linear  inch.  Not  more 
than  y2  ounce  of  either  Portland  or  natural  cement  should  remain  on 
sieve.  To  compare  quality  of  two  brands  otherwise  similar,  sift 
through  a  200-mesh  sieve  and  choose  the  finer  cement."* 

179.    STRENGTH  TESTS  FOR  PORTLAND  CEMENTS.— 

*  "Concrete,  Plain  and  Reinforced."    Taylor  and  Thompson. 


176 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


As  was  stated  under  this  subdivision  of  natural  cements,  a  brief 
description  of  the  manner  of  applying  strength  tests  to  cement  is  - 
given  in  division  6,  of  this  chapter,  entitled  ''Strength  Tests  for 
Cements."    A  standard  requirement,  however,  will  be  given  here. 

The  requirements  for  tensile  strength  of  Portland  cement,  as 
given  in  the  specifications  of  the  American  Society  for  Testing  Ma- 
terials, 1904,  are  as  follows : 

"The  minimum  requirements  for  tensile  strength  for  briquettes 
one  inch  square  in  section  shall  be  w^ithin  the  following  limits,  and 


shall  show  no  retrogression  in  strength  within  the  periods  specified: 

Age.  NEAT  CEMENT.  Strength. 

24  hours  in  moist  air  150-200  pounds. 

7  days  (i  day  in  air,  6  days  in  water)  450-550  pounds. 

28  days  (i  day  in  air,  27  days  in  water)  550-650  pounds. 

ONE  PART  CEMENT,  THREE  PARTS  SAND. 

7  days  (i  day  in  air,  6  days  in  water)  150-200  pounds. 

28  days  (i  day  in  air,  27  days  in  water)  200-400  pounds." 


The  tensile  test  is  the  one  most  commonly  applied  strength  test, 
because  it  is  difficult  to  make  an  accurate  compressive  test.  The 
ratio  between  compressive  and  tensile  strength  is  quite  uniform,  and 
is  aboiit  10. 

For  a  list  of  other  "Strength  Tests  of  Cements  and  Cement 
Mortars,"  and  a  list  of  the  "Special  Tests  of  Cements  and  Mortars" 
see  Articles  166  and  167  under  the  subject  "Natural  Cements." 

180.  SPECIFICATIONS  FOR  PORTLAND  CEMENTS.— 
As  was  stated  under  this  heading  for  natural  cements,  the  specifica- 
tions for  the  cement  for  any  operation  are' based  upon  the  result  of 
tests,  upon  experience  and  practice,  and  upon  the  study  of  model 
requirements  for  the  most  recent  and  approved  modern  works. 

The  set  of  specifications  given  under  natural  cements  and  the  fol- 
lowing set  here  are  sufficient  to  indicate  the  general  form,  the  details 
of  the  requirements,  of  course,  differing  for  Portland  cement.  It 
is  not  possible  here  to  give  the  dififerent  specifications  for  the  latter, 
and  the  reader  is  referred  to  various  treatises  on  cements,  and  to 
the  bibliographies  of  cement  specifications  published  here  and  else- 
where. 

One  most  excellent  set  is  given,  however,  the  specifications  for 
Portland  cement,  based  upon  the  practice  of  Engineers  F.  W.  Taylor 
and  S.  E.  Thompson,  supplemented  by  a  careful  study  of  the 
specifications  of  the  following:  American  Society  for  Testing  Ma- 


PORTLAND  CEMENTS. 


^77 


terials,  American  Railway  Engineering  and  Maintenance-of-Way 
Association,  City  of  Philadelphia,  United  States  Army,  United  States 
Navy,  Massachusetts  Metropolitan  Commissions,  New  York  Rapid 
Transit  Commission,  and  others. 

1.  Packages. — Cement  shall  be  packed  in  strong  cloth  or  canvas 
sacks. t  Each  package  shall  have  printed  upon  it  the  brand  and  name 
of  the  manufacturer.  Packages  received  in  broken  or  damaged  con- 
dition may  be  rejected  or  accepted  as  fractional  packages. 

2.  Weight. — Four  bags  shall  constitute  a  barrel,  and  the  average 
net  weight  of  the  cement  contained  in  one  bag  shall  be  not  less  than 
94  pounds  or  376  pounds  net  per  barrel.  A  cement  bag  may  be 
assumed  to  weigh  one  pound.  The  weights  of  the  separate  packages 
shall  be  uniform. 

3.  Requirements.^ — Cement  failing  to  meet  the  seven-day  re- 
quirements may  be  held  awaiting  the  results  of  the  twenty-eight-day 
tests  before  rejection. 

4.  Tests."^ — All  tests  shall  be  made  in  accordance  with  the  meth- 
ods proposed  by  the  Committee  on  Uniform  Tests  of  Cement  of  the 
American  Society  of  Civil  Engineers,  presented  to  the  society  Jan- 
uary 21,  1903,  and  amended  January  20,  1904,  with  all  subsequent 
amendments  thereto. 

5.  Sampling. — Samples  shall  be -taken  at  random  from  sound 
packages,  and  the  cement  from  each  package  shall  be  tested  sep- 
arately. 

6.  *  The  acceptance  or  rejection  shall  be  based  on  the  following 
requirements : 

7.  Definition  of  Portland  Cement.^ — This  term  is  applied  to  the 
finely  pulverized  product  resulting  from  the  calcination  to  incipient 
fusion  of  an  intimate  mixture  of  properly  proportioned  argillaceous^ 
and  calcareous§  materials,  and  to  which  no  addition  greater  than 
3  per  cent  has  been  made  subsequent  to  calcination. 

8.  Specific  Gravity."^ — The  specific  gravity  of  the  cement,  thor- 
oughly dried  at  100°  Cent.  (212°  Fahr.),  shall  be  not  less  than  3.10. 

9.  Fineness."^ — It  shall    leave  by  weight  a  residue  of  not  more 

*Paragraphs  designated  by  an  asterisk  are  quoted  from  the  Standard  Specifications 
of  the  American  Society  for  Testing  Materials. 

+If  the  cement  is  to  be  stored  in  a  damp  place  or  near  the  sea,  it  must  be  packed 
in  well-made  wooden  barrels  lined  with  paper. 

If  stored  in  a  dry  place  to  be  used  immediately,  it  may  be  packed  in  stout  cloth 
or  canvas  bags  which  are  of  course  cheaper  than  barrels. 

%  Clayey. 

§  Consisting  chiefly  of  lime  or  calcium. 


178  BUILDING  CONSTRUCTION.  (Ch.  IV) 

than  8  per  cent  on  the  No.  loo,  and  not  more  than  25  per  cent  on  the 
No.  200  sieve. 

10.  Time  of  Setting."^ — It  shall  develop  initial  set  in  not  less  than 
thirty  minutes,  but  must  develop  hard  set  in  not  less  than  one  hour 
nor  more  than  ten  hours. 

11.  Tensile  Strength.^ — Briquettes  one  inch  square  in  section 
shall  attain  at  least  the  following  tensile  strengths  and  shall  show  no 
retrogression  within  the  periods  specified: 

Age.  NEAT  CEMENT.  Strength.f 

24  hours  in  moist  air   175  lbs. 

7  days  (i  day  in  air,  6  days  in  water)   500  lbs. 

28  days  (i  day  in  air,  27  days  in  water)   600  lbs. 

ONE  PART  CEMENT,  THREE  PARTS  STANDARD  SAND. 
Age.  Strength.f 

7  days  (i  day  in  moist  air,  6  days  in  water)   150  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   200  lbs. 

12.  Soundness  or  Constancy  of  Volume. — Pats  of  neat  cement 
about  three  inches  in  diameter,  one-half  inch  thick  at  the  center,  and 
tapering  to  a  thin  edge,  shall  be  kept  in  moist  air  for  a  period  of 
twenty-four  hours. 

{a)  A  pat  is  then  kept  in  air  at  normal  temperature,  and  observed 
at  intervals  for  at  least  28  days. 

(b)  Another  pat  is  kept  in  water  maintained  as  near  70  de- 
grees Fahr.  as  practicable,  and  observed  at  intervals  for  at  least 
28  days. 

(c)  A  third  pat  is  exposed  in  any  convenient  way  in  an  atmos- 
phere of  steam,  above  boiling  water,  in  a  loosely  closed  vessel  for 
five  hours. 

These  pats  to  satisfactorily  pass  the  requirements  shall  remain 
firm  and  hard  and  show  no  signs  of  distortion,  checking,  cracking 
or  disintegration. 

13.  Sulphuric  Acid  and  Magnesia. — The  cement  shall  not  con- 
tain more  than  1.75  per  cent  of  anhydrous  sulphuric  acid  (SO3), 
nor  more  than  4  per  cent  of  Magnesia  (MgO). 

In  writing  on  "Specifications  for  Portland  Cement,"  Mr.  Edwin 

*Paragraplis  designated  by  an  asterisk  are  quoted  from  the  Standard  Specifications  of 
the  American  Society  for  Testing  Materials. 

tThe  American  Society  for  Testing  Materials  gives  minimum  requirements  as  fellows- 
Neat  Cement — 24  hours,  150-200  lb.;  7  days,  450-550  lb.;  28  days,  550-650  lb.  1:3  mortar— 
7  days,  150-200  lb.;  28  days,  200-300  lb.;  the  exact  values  to  be  fixed  in  each  case  by 
the  consumer. 


PUZZOLAN  CEMENTS. 


1/9 


C.  Eckel"^  has  collected  and  published  various  specifications,  and 
states  that  they  are  of  interest  partly  for  comparison  and  partly  to 
show  the  growth  of  intelligent  treatment  of  the  subject.  He  also 
states  that  the  specifications  of  the  American  Society  for  Testing 
Materials  will  probably  become  the  standard  in  this  country. 

181.  MISCELLANEOUS  DATA  AND  AIEMORANDA  ON 
PORTLAND  CEMENTS.— Reference  should  here  be  made  to  the 
corresponding  Article,  169,  under  Natural  Cements,  as  occasional 
data  these  are  for  Portland  Cements, 

The  following  are  some  useful  notes  compiledt  to  show  the 
weights  and  measurements  of  contents  of  a  barrel  of  Portland 
cement.    (See  also  Article  178.) 

A  barrel  of  Portland  cement  weighs  about  380  pounds  net. 

A  barrel  of  Portland  cement  weighs  about  400  pounds  gross. 

A  barrel  of  Portland  cement  contains  about  3.40  cubic  feet 
packed. 

A  barrel  of  Portland  cement  contains  about. 4. 25  cubic  feet  loose. 
A  barrel  of  Portland  cement  contains  about  2.73  bushels  packed. 
A  barrel  of  Portland  cement  contains  about  3.61  bushels  loose. 

182.  THE  CHOICE  OF  PORTLAND  CEMENTS,  AND 
THE  SELECTION  OF  BRANDS.— The  reader  is  here  referred 
to  Article  170,  under  Natural  Cements,  wuich  considered  the  ques- 
tion of  deciding  between  the  two  classes  of  cements  in  any  case, 
and  also  the  question  of  the  selection  of  some  particular  brand  of 
either. 

5.    PUZZOLAN  CEMENTS. 

183.  CLASSIFICATION. — The  puzzolan  cements  belong  to 
the  silicate  division  of  the  complex  cementing  materials.  They 
differ  from  the  other  three  classes  of  the  silicate  cements,  the 
hydraulic  limes',  natural  cements  and  Portland  cements,  as  their  raw 
materials  are  not  calcined  after  mixture. 

184.  DEFINITION  OF  PUZZOLAN  CEMENT.— Puzzolan 
cement  is  a  mechanical  mixture  of  certain  natural  or  artificial 

*  "Cements,  Limes  and  Plasters."    Edwin  C.  Eckel. 
The  following  is  the  list  of  these  specifications: 

1.  New  York  State  Canals.  1896. 

2.  Rapid  Transit  Subway,  New  York  City.  1900-1901. 

3.  Department  of  Bridges,  New  York  City.  1901. 

4.  Engineer  Corps.    U.  S.  Army.  1902. 

5.  U.  S.  Reclamation  Service.  1904. 

6.  Canadian  Society  of  Civil  Engineers.  1503. 

i  7.  Cohcrete-Steel  Engineering  Company.  1903. 

.8.  British  Standard  Specifications.  1905. 
,  9.  American  Society  for  Testing  Materials.  '  1904. 

t  "Handbook  for  Superintendents  of  Construction."    H.  G.  Richey. 


i8o  BUILDING  CONSTRUCTION.  (Ch.  IV) 


products,  such  as  volcanic  ash  or  blast-furnace  slag,  with  powdered 
slaked  lime.  The  term  piiz::olan  has  been  adopted  by  many  authori- 
ties and  is  now  in  general  use.  The  material  was  first  obtained  near 
the  town  of  Pozzuoli,  a  few  miles  west  of  Naples,  from  which  place 
the  Italian  poz:::iiolana  takes  its  name. 

185.  THE  CHEMICAL  ANALYSIS  OF  PUZZOLAN 
CEMENTS. — In  Article  157  on  the  "Classification  of  Cementing 
Materials,"  in  Table  IX,  "Typical  Analyses  of  Cements,"  the  average 
chemical  analysis  is  given.  The  puzzolanic  materials  in  composi- 
tion are  made  up  largely  of  silica  and  alumina,  and  usually  with 
more  or  less  iron  oxide ;  and  some  of  these  materials,  such  as  the 
slags  used  in  cement-manufacture,  contain  in  addition  notable  per- 
centages of  lime. 

186.  THE  MANUFACTURE  OF  PUZZOLAN  CEMENTS.— 
Puzzolanic  materials  include  the  (i)  natural  and  (2)  the  artificial 
materials.  To  the  first  class  belong  the  direct  products  of  volcanic 
action,  and  to  the  second  class  the  blast-furnace  slag  and  some  other 
artificial  materials,  such  as  burnt  clay. 

In  using  the  natural  materials,  they  are  dug  out  from  the  deposits, 
screened  and  ground  and  occasionally  slightly  roasted  to  increase 
their  hydraulic  properties. 

In  using  the  artificial  materials,  as  blast-furnace  slag,  no  kilns 
are  used,  and  the  molten  slag  coming  from  the  furnace  is  chilled 
and  granulated  by  a  stream  of  cold  water,  and  separated  from  most 
of  its  sulphur.  It  is  then  dried  and  may  or  may  not  have  a  pre- 
liminary grinding  before  the  addition  of  the  slaked  lime. 

The  production  of  puzzolan  cement  in  the  United  States  in  1906 
was  481,224  barrels,  valued  at  $412,921. 

An  advantage  of  this  industry  lies  in  the  fact  that  it  utilizes  and 
consumes  a  product  of  steel  and  iron  foundries  which  has  for  years 
been  troublesome  to  dispose  of  and  regarded  as  a  waste  product. 

187.  THE  USES  OF  PUZZOLAN  CEMENTS.— The  follow- 
ing are  the  generally  accepted  conclusions  regarding  the  proper  uses 
of  puzzolan  cement : 

( 1 )  It  never  becomes  extremely  hard,  like  Portland  cement. 

(2)  Puzzolan  mortars  are  tougher  or  less  brittle  than  Portland 
cements. 

(3)  It  is  well  adapted  for  use  in  sea-water. 

(4)  It  is  well  adapted  for  use  in  all  positions  constantly  exposed 
to  moisture. 


PUZZOLAN  CEMEXTS. 


i8i 


(5)  It  is  suitable  for  use  in  foundations  of  buildings  in  damp 
places. 

(6)  It  may  be  used  in  sewers,  drains  and  in  underground  works 
generally. 

(7)  It  may  be  used  in  the  interior  of  heavy  masses  of  masonry 
or  concrete. 

(8)  It  is  not  suitable  for  use  in  any  positions  subjected  to 
mechanical  wear,  attrition  or  blows,  and  it  should  not  be  employed 
in  places  where  it  is  liable  to  be  exposed  for  long  periods  to  dry 
air,  even  after  it  has  reached  its  hardest  set. 

(9)  It  has  a  tendency  to  change  to  a  whitish  color  and  to  dis- 
integrate, on  account  of  the  oxidation  of  its  sulphides  at  and  near 
the  surface,  when  exposed  to  dry  air  as  mentioned  in  (8). 

188.  CHARACTERISTICS  AND  PROPERTIES  OF  PUZ- 
ZOLAN CEMENTS. — Color. — Puzzolan  cement  made  from  slag 
can  usually  be  distinguished  from  Portland  cement  bv  its  decidedly 
lighter  color  and  slightly  different  tint,  and  from  natural  cements 
by  a  marked  difference  in  tint.  The  color  varies  from  bluish-white 
to  lilac.  This  cement  is  also  characterized  by  the  intense  bluish- 
green  color  in  the  fresh  fracture  after  long  submersion  in  water, 
diie  to  the  presence  of  sulphides,  which  color  fades  after  exposure 
to  dry  air.    Slag  cements  do  not  stain  masonry. 

Weight. — Slag  cement  weighs  about  350  pounds  gross,  or  330 
pounds  net,  per  barrel. 

Specific  Gravity. — The  slag  cements  are  lighter  than  the  Portland 
cements,  and  for  the  same  weight  more  bulk  is  obtained.  The  usual 
range  of  variation  in  the  specific  gravity  of  the  slag  cements  is  from 
2.7  to  2.9,  as  compared  with  the  fair  average  3.15  for  good  Portland 
cement. 

Activity  or  Time  of  Setting. — Slag  cements  are  generally  slower 
setting  than  Portland  cements.  The  use  to  which  the  cement  is  put 
determines  whether  or  not  slow  set  is  desirable.  Rapidity  of  set 
varies  decidedly  with  the  amount  of  alumina  in  the  slag.  Burned 
clay,  active  forms  of  silica,  slags  high  in  alumina,  etc.,  when  added 
hasten  the  set.    Alkalies  a||felerate  the  set. 

Soundness  or  Constancy  of  Volume. — To  test  the  soundness,  pats 
of*  neat  cement  mixed  for  five  minutes  with  18  per  cent  of  water  by 
weight  are  made  on  glass,  each  pat  about  3  inches  in  diameter  and 
an  inch  thick  at  the  center,  tapering  thence  to  a  thin  edge.  They 
are  kept  under  wet  cloths  until  finally  set,  when  they  are  placed  in 


l82 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


fresh  water.  They  should  not  show  distortion  or  cracks  at  the  end 
of  twenty-eight  days. 

Fineness. — Ninety-seven  per  cent  of  the  puzzolan  or  slag  cement 
should  pass  through  a  sieve  made  of  No.  40  wire,  Stubbs'  gauge^ 
having  10,000  openings  per  square  inch. 

189.  STRENGTH  OF  PUZZOLAN  OR  SLAG  CEMENTS.— 
Slag  cements  approximate  in  tensile  strength  similar  mixture  of 
Portland  cements.  In  compressive  strength,  however,  their  resist- 
ance is  less,  the'  ratio  of  compressive  to  tensile  strength  being  about 
from  5  to  7  to  I  for  slag  cements,  and  from  9  to  11  to  i  for  Portland 
cements.  Slag  cements  also  often  give  nearly  as  great  tensile 
strength  in  3  to  i  mixtures  as  in  neat  briquettes,  this  being  due 
to  the  fact  that  they  are  ground  very  fine. 

190.  SPECIFICATIONS  FOR  PUZZOLAN  CEMENTS.— 
Detailed  specifications  for  puzzolan  cements  have  been  prepared 
and  published  by  the  Engineer  Corps,  U.  S.  Army,  and  are  to 
be  found  in  most  of  the  treatises  on  limes,  cements,  mortars  and 
concretes.* 

6.    STRENGTH  TESTS  FOR  CEMENTS. 

191.  STRENGTH  TESTS  IN  GENERAL.— The  object  of 
strength  tests  for  cement  mortars  is  to  determine  their  strength  in 
actual  work.  As  it  is  easier  to  make  the  test  for  tension  than  for 
compression,  shear,  flexure,  adhesion,  etc.,  and  as  the  tensile 
strength  bears  a  generally  constant  relation  to  these  other  stresses, 
it  is  the  tension  test  that  is  usually  made.  The  tests  are  made  on 
neat  cement  and  on  cement  mixed  with  varying  proportions  of 
sand.  The  former  indicate  the  character  and  quality  of  the  material, 
the  latter  the  strength  under  actual  conditions.  (See  also  Articles 
166  and  208.) 

For  Portland  cement,  sand  mixture  tests,  i  part  by  weight  of 
cement  to  3  parts  of  sand  are  used ;  and  for  natural  and  slag 
cements,  i  to  i  and  i  to  2.  The  briquettes  are  broken  at  periods 
of  24  hours,  7  days,  and  28  days  for  neat  tests,  longer  periods  being 
necessary  for  special  experimental  purposes. 

192.  NORMAL  CONSISTENCY^.  OF  MORTAR.— This 
means  the  use  of  a  proper  percentage  of  water  in  making  the  pastes 
for  the  pats,  briquettes,  etc.  Various  methods  are  followed  for 
making  this  determination.    A  simple  method  is  to  mix  the  cement 


*  Among  other  books  in  which  these  specifications  are  published  is  "Cements,  Limes 
and  Plasters,"  by  Edwin  C.  Eckel. 


STRENGTH  TESTS  FOR  CEMENTS.  183 


 1 — 

i 

i 
1 

1 
1 

1 
1 

♦ 

• 
1 

Fig.  89.    Standard  American  Form  of  Cement  Briquette. 


paste  to  such  a  degree  of  plasticity  that  when  a  ball  of  the  paste  2 
inches  in  diameter  is  dropped  upon  a  hard  surface  from  a  height  of 
2  feet  it  will  not  crack  or  flatten  more  than  half  its  original  thick- 
ness. 

193.  FORM  OF  BRIQUETTE.— The  standard  American  form 
of  briquettes,  with  which  the  tensional  tests  are  usually  made,  is 
shown  in  Fig.  89.  This  is  the  form  adopted  by  the  Special  Com- 
mittee on  Uniform  Tests  of  Cement  of  the  American  Society  of 
Civil  Engineers.  The  minimum  cross-sectional  area  is  one  square 
inch.  The  molds  are  made  of  brass,  and  are  either  single  or  in 
gangs  of  three  or  four,  as  shown  in  Fig.  90.  In  making  the  tests 
a  solid  metal  clip  of  the  form  shown  in  Fig.  91  is  used  without 
-cushioning  at  the  points  of  contact.    The  bearing  is  %  of  an  inch 


i84  BUILDING  CONSTRUCTION.  (Ch.  IV) 


wide,  and  the  distance  between  centers  of  contact  on  same  clip  should 
he  i}i  inches. 

194.  METHOD  OF  MIXING.— A  careful  determination  by 
weight  of  the  proportions  of  cement,  sand  and  water  is  made,  the 
sand  and  cement  mixed  dry,  and  the  water  added  all  at  once.  A 
rapid  and  thorough  mixing  of  the  mortar  then  follows,  and  when 
it  is  stiff  and  plastic  it  is  pressed  firmly  into  the  molds  with  a 
trowel,  without  ramming,  and  struck  off  level.    The  mixing  is  done 


Fig.  90.    Gang-Mold  for  Cement  Briquettes. 


FORM  OF  CLIP. 

Fig.  91.    Standard  Metal  Clip  for  Testing 
Cement  Briquettes. 


Upon  a  glass  or  slate  slab,  the 
hands  being  protected  by  rubber 
gloves. 

195.  STORING  THE  BRI- 
QUETTES OR  TEST  PIECES. 
During  the  first  24  hours  after 
molding,  the  test  pieces  are  stored 
in  a  damp  atmosphere  to  prevent 
them  from  drying  out.  They  are 
then  immersed  in  water  until 
tested. 

196.  TESTING  MACHINES. 
— There  are  many  testing  ma- 
chines in  use,  all  of  them  rather 
expensive.  When  properly  used, 
any  one  of  them  will  give  satis- 
factory results.  These  machines 
and  their  detailed  operation  are 
discussed  and  illustrated  in  the 
treatises  on  these  subjects. 

A  home-made  testing  machine 
of  low  cost  is  shown  in  Fig.  92. 

It  can  be  made  by  an  ordinary 
mechanic  at  small  expense.  It  is 
not  as  convenient  nor  quite  as 


STRENGTH  TESTS  FOR  CEMENTS. 


185 


accurate  as  the  more  elaborate  machines,  but  it  is  sufficiently  accurate 
for  all  practical  purposes.  "The  machine  consists  essentially  of  a 
counterpoised  wooden  lever,  10  feet  long,  working  on  a  horizontal 
pin,  between  two  broad  uprights,  20  inches  from  one  end.  Along 
the  top  of  the  long  arm  runs  a  grooved  wheel  carrying  a.  weight, 
W.  The  distances  from  the  fulcrum  in  feet  and  inches  are  marked 
on  the  surface  of  the  lever,  and  also  the  corresponding  effect  of  the 
weight  at  each  point.  The  clamp  for  holding  the  briquette  is  sus- 
pended from  the  short  arm,  18  inches  from  the  fulcrum.  The 
clamps  are  of  wood  and  are  fastened  by  clevis  points  to  the  lever* 
^  arm  and  bed-plate  respectively.  The  pin  is  iron  and  the  pin  holes 
are  reinforced  by  iron  washers.  When  great  stresses  are  required 
extra  weights  are  hung  on  the  end  of  the  long  arm.  Pressures  of 
3,000  pounds  have  been  developed  with  this  machine." 


Fig.   92.    Simple  Machine  for  Approximate  Cement  Tests. 

In  applying  the  load  on  the  briquette  it  is  recommended  that  it 
start  at  o  and  be  increased  regularly  at  the  rate  of  400  pounds  per 
minute  for  neat  Portland  cements,  and  200  pounds  per  minute  for 
natural  cements  and  mortar. 

A  rough  test  may  be  made  by  suspending  the  clamps  from  a  beam 
or  trestle  and  hanging  a  bucket  or  box  from  the  lower  clamp,  into 
which  sand  is  run  until  the  briquette  breaks,  when  the  sand  is 
weighed. 

197.  TENSILE  STRENGTH  OF  CEMENT  MORTARS.— 
Tests  of  tensile  strength  are  made  to  determine  the  strength  which 
w'lW  develop  in  a  certain  time,  and  the  ultimate  strength.  A  cement 
should  never  decrease  in  strength.  The  usual  stipulations  are  that 
the  materials  must  pass  a  minimum  strength  acquirement  at  7  and 
28  days. 

The  sand  test  is  the  true  criterion  of  strength,  and  there  should 
be  no  acceptance  of  any  cement  failing  to  satisfactorily  pass  it,  even 
though  the  neat  tests  have  not  failed. 

Cement  and  cement  mixtures  attain  a  strength  not  differing 
greatly  from  the  ultimate  strength  within  a  period  of  three  months 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


from  the  time  of  setting,  and  practically  within  a  month  or  so 
after  this  period  no  appreciable  change  of  strength  takes  place.* 

The  following  tablet  gives  the  approximate  values  for  the  tensile 
strength  of  first-class  Portland,  natural  and  slag  cements  in  neat 
and  sand  tests : 

TABLE  XIV. 

Tensile  Strengths  of  Portland,  Natural  and  Slag  Cements. 


PORTLAND  CEMENT. 
Age.  Neat.  Strength. 

24  hours  (in  moist  air)  •   175  lbs. 

7  days  (i  day  in  moist  air,  6  days  in  water)   500  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   600  lbs. 

Age.  One  Part  Cement,  Three  Parts  Sand.  Strength. 

7  days  (i  day  in  moist  air,  6  days  in  water)   170  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   240  lbs. 

NATURAL  CEMENT. 
Age  Neat.  Strength. 

24  hours  (in  moist  air)   40  lbs. 

7  days  (i  day  jn  moist  air,  6  days  in  water)   125  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   225  lbs. 

Age  One  Part  Cement,  Two  Parts  Sand.  Strength. 

7  days  (i  day  in  moist  air,  6  days  in  water)   75  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   140  lbs. 

SLAG  CEMENT. 

Age  Neat.  Strength. 

7  days  (i  day  in  moist  air,  6  days  in  water)   350  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   500  lbs. 

Age.  One  Part  Cement,  Three  Parts  Sand.  Strength. 

7  days  (i  day  in  moist  air,  6  days  in  water)   140  lbs. 

28  days  (i  day  in  moist  air,  27  days  in  water)   220  lbs. 


198.  COMPRESSIVE  STRENGTH-  OF  CEMENT  MOR- 
TARS.— Compression  tests  of  cement  are  not  generally  made  in 
the  United  States,  although  they  are  made  in  Europe.  When  they 
are  made  the  ends  of  the  specimens  broken  in  tension  are  often 
used  in  making  the  test.  The  ratio  of  the  compressive  to  the  tensile 
strength,  in  natural  cements  and  slag  cemicnts,  seems  to  be  lower 
than  in  Portland  cements,  in  which  latter  it  may  be  taken  as  10. 
For  natural  cem.ent  the  average  ratio  is  4.9,  and  for  slag  cements 
5.3,  as  determined  by  a  series  of  tests.     See  also  Article  208, 

*  See  "Cements.  Mortars'  and  Concrete."    Myron  S.  Falk. 

+  "Concrete  and  Reinforced  Concrete  Construction."    Homer  A.  Reid. 


STRENGTH  TESTS  TOR  CEMENTS. 


187 


"Strength  of  Mortar,"  and  Article  189,  ''Strength  of  Puzzolan  or 
Slag  Cements." 

199.  OTHER  STRENGTH  PROPERTIES.— rra;zj^'rr^^  or 
Flexure  Tests  have  been  made  on  beams  and  prisms  of  cement  mor- 
tars, but  are  now  seldom  used.  Their  principal  value  is  in  compar- 
ing the  direct  tensional  stress  with  the  tensile  fiber  stress  due  to 
flexure. 

A  relation  has  been  determined  between  the  ultimate  tensile  and 
Hexiiral  fiber  stresses  of  cement  mortar  briquettes,  and  the  tensile 
flexural  fiber  stress  has  been  found  from  several  series  of  careful 
experim.ents  to  be  1.9  times  the  simple  direct  tensile  stress  of  the 
same  material.* 

Tests  have  been  made  to  determine  the  adhesive  strength  of 
cement  m.ortars.  There  is  a  great  variation  in  the  adhesive  strength 
of  mortars  made  from  dififerent  cements. 

The  adhesion  of  mortar  to  a  stone  or  brick  surface  depends  upon 
the  state  of  the  surface  and  the  nature  of  the  cement  used.  It  is 
less  than  the  tensile  strength  of  the  mortar. f  The  adhesion  increases 
as  the  surface  receiving  the  mortar  becomes  more  porous.  Irregu- 
larities of  the  surface  of  stone  do  not  seem  to  afifect  the  adhesive 
strength,  but  with  iron,  roughening  the  surface  increases  the 
adhesion  of  the  mortar.  A  dirty  surface  or  insufiicient  moistening 
of  the  surface  lowers  the  adhesion.  The  average  ultimate  adhesive 
strength  of  cement  mortar  to  brick  surfaces  may  be  taken  at  from 
25  to  85  pounds  per  square  inch. 

In  the  use  of  iron  or  steel  for  reinforcement,  and  the  setting  of 
bolts  in  mortar  and  concrete,  the  whole  question  of  the  adhesion 
of  mortar  to  iron  or  steel  is  one  of  great  importance,  but  belongs  to 
discussions  in  connection  with  reinforced  concrete.  From  200  to 
500  pounds  per  square  inch  may  be  taken  as  average  figures  for  the 
ultimate  adhesive  strength  of  cement  mortar  to  iron  rods  or  bolts 
imbedded  in  it. 

See  also  in  Article  209,  'The  Adhesion  of  Mortars." 

Shearing  tests  have  been  made  upon  dififerent  mortars,  and  the 
shearing  resistances  for  Portland  cement  mortars  found  to  be  very 
much  less  than  the  compressive  resistance. 4: 

*  M.  Durand-Claye  in  "Commission  des  Methodes  d'Essai  des  Materiaux  de  Construc- 
tion," 1895,  Vol.  IV,  p.  211. 

+  "A'lechanics  of  Materials."    Mansfield  Merriman. 

%  For  a  comparison  of  Flexural,  Tensional,  Compressive  and  Shearing  Strength  of 
Portland  Cement  Mortars,  see  very  comprehensive  tables  in  Chapter  IX  of  "Concrete, 
Plain  and  Reinforced,"  by  Taylor  and  Thompson. 


188 


BUILDING  CONSTRUCTION. 


(Cii.  IV) 


.  The  coefficient  of  elasticity  of  American  natural  cements  has  been 
found  to  vary  from  500,000  to  1,800,000  pounds  per  square  inch, 
and  of  American  Portland  cements  from  2,300,000  to  4,500,00a 
pounds  per  square  inch. 

7.    CEMENT  MORTARS. 

200.  USE. — Cement  mortar  should  be  used  for  all  mason  work 
which  is  below  grade,  or  situated  in  damp  places,  and  also  for 
heavily  loaded  piers  and  arches  of  large  span.  It  should  be  used 
for  setting  coping  stones,  and  wherever  the  mason  work  is  especially 
exposed  to  the  weather. 

For  construction  under  water,  and  in  heavy  stone  piers  or  arches, 
and  for  concrete,  Portland  cement  should  be  used ;  elsewhere  natural 
cement  mortar  will  answer. 

See  also  the  articles  relating  to  the  *'Uses"  of  the  various  cements. 

201.  MIXING  THE  MORTAR.— The  following  are  directions 
for  hand  mixing  cement  mortar  for  ordinary  masonry :  Spread 
about  half  the  sand  required  for  mixing  evenly  over  the  bed  of  the 
mortar  box  (which  should  be  water-tight),  and  then  spread  the  dry 
cement  evenly  over  the  sand  and  spread  the  remaining  sand  on  top. 
Thoroughly  mix  the  dry  sand  and  cement  with  a  hoe  or  shovel,  as 
this  is  a  very  essential  part  of  the  process.  Shovel  the  dry  mixture 
to  one  end  of  the  box  and  pour  water  into  the  other  end.  ("Cements 
vary  greatly  in  their  capacity  for  water,  freshly-ground  cements  re- 
quiring more  than  those  that  have  become  stale.  An  excess  of  water 
is,  however,  better  than  a  deficiency,  particularly  when  a  very  ener- 
getic cement  is  used,  as  the  capacity  of  this  substance  for  absorbing 
water  is  great.")  Draw  down  with  a  hoe  the  sand  and  cement  in 
small  quantities  and  mix  with  the  water  until  enough  has  been  added 
to  make  a  good  stiff  mortar,  taking  care  not  to  get  it  too  thin.  Work 
the  mortar  vigorously  with  a  hoe  for  five  minutes  to  get  a  thorough 
mixture. 

The  mortar  should  leave  the  hoe  clean  when  drawn  out  of  it, 
very  little  sticking  to  the  steel.  But  a  very  small  quantity  of  cement 
mortar  should  be  mixed  at  a  time,  particularly  that  made  of  nat- 
ural cements,  as  mortars  made  from  these  cements  soon  commence 
to  set,  after  which  they  should  not  be  used.  As  a  rule  natural 
cement  mortars  should,  not  be  used  after  they  have  been  mixed  two 
hours,  and  Portland  cement  mortars  after  four  hours  (for  best 
work  not  over  one  hour). 


CEMENT  MORTARS.  189 

t  The  sand  and  cement  should  not  be  mixed  so  as  to  stand  over 
night,  as  the  moisture  in  the  sand  will  destroy  the  setting  qualities 
of  the  cement. 

Mechanical  mixtures  are  frequently  used  in  large  operations,  with 
a  lessening  of  the  labor  of  manipulating  the  materials,  and,  when 
employed  with  great  care,  with  a  uniformity  of  good  work.  The 
principal  objection  to  these  mixer^  is  the  failure  to  thoroughly  inter- 
mix the  dry  cement  and  sand,  and  the  temptation  to  lighten  the  labor 
of  the  wet  mixing  by  giving  an  overdose  of  water. 

202.  KEEPING  CEMENT  MORTARS  MOIST.— ''Hydraulic 
cements  set  better  and  attain  a  greater  strength  under  water  than  in 
the  open  air ;  in  the  latter,  owing  to  the  evaporation  of  the  water, 
the  mortar  has  a  tendency  to  dry  rather  than  to  set.  This  difference  is 
very  marked  in  hot,  dry  weather.  If  cement  mortar  is  to  be  ex- 
posed to  the  air  it  should  be  shielded  from  the  direct  rays  of  the 
sun  and  kept  moist." 

203.  PROPORTION  OF  SAND.— "A  paste  of  good  hydraulic 
cement  hardens  simultaneously  and  uniformly  throughout  the  mass, 
and  its  strength  is  impaired  by  any  addition  of  sand."  As  mortar 
is  never  used  by  itself,  however,  but  as  a  binding  material  for  brick 
and  stone,  and  there  can  obviously  be  no  advantage  in  making  the 
strength  of  the  mortar  joints  greater  than  that  of  the  bricks  or 
stones  they  unite,  sand  is  always  added  to  the  cement  in  making 
mortar.  Sand  also  generally  reduces  the  tendencies  to  shrink  and 
crack,  especially  in  lime  mortar.  As  cement  is  much  more  expensive 
than  sand,  the  larger  the  proportion  of  sand  in  the  mortar  the  less 
will  be  its  cost.  The  proportion  of  sand  should  vary  according  to 
the  kindfDf  cement  and  the  kind  of  work  for  which  the  mortar  is  to 
be  used.  For  natural  cements  the  proportion  of  sand  to  cement  by 
measurement  should  not  exceed  3  to  i,  and  for  piers  and  first- 
class  work  2  to  I  should  be  used.  Portland  cement  mortar  may- 
contain  4  parts  of.  sand  to  i  of  cement  for  ordinary  mortar,  and  3 
to  I  for  first-class  mortar.  For  work  under  water  not  more  than 
2  parts  of  sand  'to  i  of  cement  should  be  used.  When  cheaper 
mortars  than  these  are  desired  it  will  be  better  to  add  lime  to  the 
mortar  instead  of  more  sand. 

The  following  are  the  proportions  of  cement  and  sand  generally 
used  for  some  specific  purposes: 

,  For  masonry  and  brickwork,  i  part  cement  to  2,  3,  or  4  parts  of 
sand,  according  to  strength  required  and  purposes  for  which  the 


igo 


BUILDING  CONSTRUCTION. 


(Ch.  IV)  . 


mortar  is  to  be  used.  For  some  special  purposes  5,  or  even  6, 
parts  of  sand  have  been  used. 

For  face  brickwork,  i  part  cement  to  2  parts  of  sand. 

For  backing  and  in  ordinary  masonry  foundations,  i  part  cement 
to  3  parts  of  sand. 

For  brick  piers  and  first-class  brickwork,  not  more  than  2  parts 
of  sand  to  i  of  natural  cement  should  be  used,  and  i  or  1^2  parts 
of  sand  will  make  a  still  stronger  mortar. 

For  cement  plastering,  equal  parts  of  natural  cement  and  sand. 

For  rubble  stonework  under  ordinary  conditions,  i  part  Portland 
cement  to  4  parts  of  sand  are  frequently  used  and  found  to  satisfy 
every  condition. 

For  top  surfaces  of  floors  and  walks,  i  part  Portland  cement  to 
from  I  to        parts  of  sand. 

The  superintendent  should  see  that  the  cement  and  sand  for  each 
batch  of  mortar  are  carefully  measured  to  get  the  right  proportions. 

To  mortars  composed  of  the  same  cement  with  different  propor- 
tions and  sizes  of  sand  two  fundamental  laws*  of  strength  may  be 
applied. 

The  first  law  is  that  with  the  same  aggregate — that  is,  the  inert 
material,  such  as  sand,  broken  stone,  etc.,  with  which  the  cement  or 
other  adhesive  material  is  mixed  to  form  mortar  or  concrete — the 
strongest  and  most  impermeable  mortar  is  that  containing  the 
largest  percentage  of  cement  in  a  given  volume  of  the  mortar. 

The  second  law  is  that  with  the  same  percentage  of  cement  in 
a  given  volume  of  mortar,  the  strongest,  and  usually  the  most 
impermeable,  mortar  is  that  which  has  the  greatest  density ;  that  is, 
the  mortar  which  in  a  unit  volume  has  the  largest  percentage  of  solid 
materials. 

Plastering  mortar,  for  stucco  work  or  waterproofing,  should  be 
made  of  i  part  cement  and  i  part  sand.  For  lining  cisterns  2  parts 
of  natural  cement  or  i  of  Portland  cement  should  be  used. 

The  following  tablef  shows  the  comparative  strength  of  English 
Portland  cement  mortar,  with  different  proportions  of  sand  and  at 
different  ages: 

•  "Concrete,  Plain  and  Reinforced."    Chapter  IX.    Taylor  and  Thomp?on.  _ 
t  This  table  shows  the  comparative  ultimate  tensile  strengths  of  some  English  neat 
cements  and  sand  mixtures.    The  reader  is  referred  to  the  numerous  and  detailed  reports  of 
recent  tests  made  on  American  cement  mortars  of  all  kinds,  and  printed  in  various  bulle- 
tins and  treatises  on  these  subjects. 


« 


CEMENT  MORTARS, 
TABLE  XV. 

Strength  of  English  Portland  Cement  Mixtures, 


AGE  AND  TIME 
IMMERSED. 

PROPORTION  OF  CLEAN  PIT  SAND  TO  I  CEMENT. 

Neat 
cement. 

I  to  I. 

2  to  I. 

3  to  I. 

4  to  I. 

5  to  I. 

445  o 
679-9 
877-9 
978.7 
995-9 
1,075-7 

152.0 
326.5 
549-6 
639.2 
718.7 
795-9 

64-5 
166.5 

451-9 
497-9 
594-4 
607.5 

44-5 
91.5 

305-3 
304-0 
383.6 
424-4 

22.0 
71.5 
153-0 
275-6 

49.0 
123.5 
218.8 

215.6 

Twelve  months  

317.6 

P.  177,  "  Notes  on  Building  Construction,"  Part  III. 


The  values  in  the  table  represent  the  breaking  strength  in  pounds 
on  a  sectional  area  of  2^4  square  inches. 

See  also  the  various  tables  and  specifications  given  in  other 
articles  of  this  chapter,  showing  the  decrease  in  strength  due  to 
larger  proportions  of  sand. 

204.  PORTLAND  AND  ROSENDALE  CEMENT,  MIXED, 
— "Mixtures  of  Portland  and  natural  cements,  unless  mixed  at  the 
factory  and  sold  as  Improved  Natural  Hydraulic  Cements,  are  not 
advised  under  any  conditions."* 

205.  CEMENT-LIME  MORTARS.— Some  constructions  re- 
quire quick-setting  mortars,  but  do  not  need  the  strength  nor  war- 
rant the  expense  of  a  i  to  2,  3  or  4  mixture  of  cement  and  sand. 
A  I  to  5  or  more  mixture  would  give  ample  strength,  but  would 
work  "short"  ;  that  is,  it  would  not  work  easily,  rapidly  and  smoothly 
on  the  trowel.  It  would  not  adhere  perfectly  to  the  stone  or  brick, 
and  could  not  be  safely  used.  The  addition  of  a  limited  quantity  of 
slaked  or  hydraulic  lime  corrects  these  faults,  results  in  a  cheaper 
mortar,  and  gives  a  mixture  suited  to  a  great  variety  of  uses.  It 
permits  the  use  of  Portland  cement  mortar  for  very  many  purposes. 

The  following  are  the  principal  advantages  of  Portland  cement- 
lime  mortar: 

■  (i)  Cheapness  in  comparison  with  other  hydraulic  materials. 

(2)  Rapidity  of  setting  and  hardening. 

(3)  Marked  hydraulic  properties. 


*See  Taylor  and  Thompson  in  "Concrete,  Plain  and  Reinforced,"  in  the  discussions 
on  "The  Choice  of  Cement"  and  "The  Class  of  Cement." 


T92  BUILDING  CONSTRUCTION.  (Cii.  IV) 

n 

{4)  Great  strength  on  exposure  to  air. 
(5)  Remarkable  resistance  to  the  weather. 

In  making  cement-lime  mortar  the  sand  and  cement  arc 
thoroughly  mixed  dry,  the  lime  putty  is  mixed  with  water  and 
screened  into  a  mortar  box,  and  the  whole  is  then  thoroughly  mixed 
and  worked  together  until  a  proper  consistency  is  obtained. 

The  following  are  mixtures  by  measure  that  have  been  used  with 
excellent  results : 

Cement  i  part,  sand  5  parts,  lime  paste  part. 
Cement  i  part,  sand  6  to  7  parts,  lime  paste,  i  part. 
Cement  i  part,  sand  8  parts,  lime  paste  13^  parts. 
Cement  i  part,  sand  10  parts,  lime  paste  2  parts. 

In  regard  to  the  strength,  a  mixture  of  Portland  cement  i,  lime 
paste  I,  sand  6,  is  as  good  as  a  mixture  of  Portland  cement  i,  sand 
3,  in  this  case  one-half  the  cement  being  replaced  without  loss  of 
strength. 

Portland  cement-lime  mortar  is  very  much  stronger,  and  little  or 
no  more  expensive  than  natural  cement-lime  mortar. 

206.  GROUT. — This  is  a  very  thin  liquid  mortar  sometimes 
poured  over  courses  of  masonry  or  brickwork  in  order  that  it  may 
penetrate  into  empty  joints  left  in  consequence  of  bad  workman- 
ship. It  is  also  sometimes  necessary  to  use  it  in  deep  and  narrow 
joints  between  large  stones.  The  mortar  may  be  neat  or  have  vari- 
ous proportions  of  sand  added,  say  from  ^  to  2  parts  to  one  part 
of  cement.  Its  use  is  not  generally  recommended  by  writers  on 
mortars,  and  the  author  believes  that  it  should  not  be  used  in  stone- 
work where  it  can  be  avoided.  For  brickwork,  however,  the  author 
feels  convinced  that  walls  grouted  with  a  moderately  thin  mortar 
every  course  makes  a  solid  job.  If  the  bricks  are  well  wet  before 
laying,  and  every  joint  slushed  full  of  stiff  mortar,  it  is  impossible 
to  get  anything  stronger;  but  in  most  localities  it  is  difficult  to  get 
such  work  without  keeping  an  inspector  constantly  on  the  ground, 
and  when  the  walls  are  grouted  the  joints  are  sure  to  be  filled.  In 
his  own  practice  the  author  always  specifies  grouting  for  all  brick 
footings  and  foundation  walls.  Many  of  the  largest  buildings  in 
New  York  City  have  grouted  walls. 

''Grouting  is  not  now  considered  a  first-class  method  of  con- 
struction. It  has,  however,  been  used  successfully  in  many  cases, 
and  will  at  times  prove  useful  when,  on  account  of  local  conditions, 


* 


CEMENT  MORTARS.  193 

other  methods  cannot  be  used.  It  has  been  successfully  used  for 
subaqueous  foundation  work  by  English  engineers,  both  in  India 
and  Europe."'^  ^ 

The  usual  method  of  mixing  is  as  follows :  The  cement  is  mixed, 
on  a  flat  platform  or  ordinary  mixing  board,  to  the  consistency  of 
stiff  paste,  and  then  placed  in  a  tub  and  slightly  thinned  down  by 
the  addition  of  water  in  small  quantities.  It  is  then  stirred  until 
the  paste  is  reduced  to  a  thick  grout,  just  soft  enough  to  leave  the 
bucket.  It  is  poured  rapidly  ;  the  faster  the  pouring  and  the  more 
continuous  the  flow  the  better  the  results  obtained.  (See  Chapter 
VII,  Article  342,  ''Grouting  Brick  Walls.") 

207.  DATA  FOR  ESTIMATES.— The  following  memoranda, 
made  up  from  data  given  by  Prof.  Ira  O.  Baker,  will  be  found  useful 
in  estimating  the  amounts  of  materials  required  in  making  any  given 
quantity  of  mortar: 

Lime  Mortar. — The  weight  of  a  barrel  of  lime  is  often  taken  at 
about  230  pounds  net ;  a  bushel  .of  lime  at  75  pounds.  At  these 
weights  one  barrel  (or  three  bushels)  of  lime  and  i  yard  of  sand 
will  make  i  yard  of  i  to  3  lime  mortar,  and  will  lay  about  80  cubic 
feet  of  rough  brickwork  or  common  rubble. 

The  following  data  are  given  by  Mr.  H.  G.  Richey : 

"i  barrel  of  lime  will  make  2^  barrels  of  paste. 
I  barrel  of  lime  will  lay  3  perches  of  stone  rubble. 
I  barrel  of  lime  will  lay  1,000  to  1,200  bricks. 
I  barrel  of  lime  will  plaster  28  yards  of  3-coat  work. 
I  barrel  of  lime  will  plaster  40  yards  of  2-coat  work. 
I  barrel  of  lime  equals  3  bushels  of  80  pounds  each."t 

Cement  Mortar. — 1.8  barrels,  or  540  pounds,  of  natural  cement 
and  .94  cubic  yard  of  sand  will  make  i  cubic  yard  of  i  to  3  mortar ; 
two  barrels,  or  675  pounds,  of  Portland  cement  and  .94  cubic  yard 
of  sand  will  also  make  i  cubic  yard  of  i  to  3  mortar;  1.7  barrels,  or 
525  pounds,  of  Portland  cement  and  .98  cubic  yard  of  sand  will  make 
I  cubic  yard  of  i  to  4  mortar ;  i  cubic  yard  of  mortar  will  lay  from 
67  to  80  cubic  feet  of  rough  rubble  or  brickwork,  from  90  to  108 
cubic  feet  of  brickwork  with  ^  to  ^-inch  joints,  and  from  324  to 
378  cubic  feet  of  stone  ashlar. 

A  cubic  foot  of  common  brickwork  contains  about  eighteen  bricks. 

See  also  Articles  169  and  181. 


*  "Concrete,  and  Reinforced  Concrete  Construction."  Homer  A.  Reid. 
+  "Handbook  for  Superintendents  of  Construction."    H.  G.  Richcy.' 


194 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


The  following  are  useful  data  which  have  been  compiled  by  Mr. 
H.  G.  Richey  to  show  "What  a  Barrel  of  Portland  Cement  Will 
Do." 

A  barrel  of  Portland  cement  will  make  about  3.15  cu.  ft.  of  neat  mortar. 
A  barrel  of  Portland  cement  will  make  about  5.4  cu.  ft.  of  mortar  mixed 
I  to  I. 

A  barrel  of  Portland  cement  will  make  about  8.5  cu.  ft.  of  mortar  mixed 
I  to  2. 


A 

barrel 

of 

Portland 

cement 

will 

make 

about 

10.7  cu.  ft.  of  mortar 

mixed  i  to  3. 

A 

barrel 

of 

Portland 

cement 

will 

make 

about 

13.5  cu.  ft.  of  mortar 

mixed 

I  to  4. 

A 

barrel 

of 

Portland 

cement 

will 

make 

about 

23  cu.  ft.  of  concrete 

mixed 

I,  3,  5- 

A 

barrel 

of 

Portland 

cement 

will 

make 

about 

26  cu.  ft.  of  concrete 

mixed 

I,  3,  6. 

A 

barrel 

of 

Portland 

cement 

will 

make 

about 

29  cu.  ft.  of  concrete 

mixed 

I,  3,  7. 

A 

barrel 

of 

Portland 

cement 

will 

make 

about 

30  cu.  ft.  of  concrete 

mixed  i,  3,  8. 

A  barrel  of  Portland  cement  (neat)  will  cover  about  40  sq.  ft.  i  in.  thick. 
A  barrel  of  Portland  cement  to  i  of  sand  will  cover  about  65  sq.  ft. 
I  in.  thick. 

A  barrel  of  Portland  cement  to  2  of  sand  will  cover  about  92  sq.  ft. 
I  in.  thick.  . 

A  barrel  of  Portland  cement  to  3  of  sand  will  cover  about  128  sq.  ft. 
I  in.  thick. 

A  barrel  of  Portland  cement  to  2  of  sand  will  lay  about  750  bricks  with 
^-inch  joints. 

A  barrel  of  Portland  cement  to  2  of  sand  will  lay  about  1,050  bricks  with 
54-inch  joints. 

A  barrel  of  Portland  cement  to  3  of  sand  will  lay  about  900  bricks  with 
^-inch  joints. 

A  barrel  of  Portland  cement  to  3  of  sand  will  lay  about  1,350  bricks  with 
J4-inch  joints. 

A  barrel  of  Portland  cement  to  3  of  sand  will  lay  about  2  perches  of 
rubble  stonework. 

208.  STRENGTH  OF  MORTAR.— This  subject  has  been 
treated  also  in  the  articles  relating  to  the  strength  of  the  different 
kinds  of  cement.  The  exact  strength  of  mortar  to  resist  compres- 
sion is  not  of  very  great  importance,  as  it  seldom,  if  ever,  fails  in 
this  way.  The  tensile  and  adhesive  strength  of  mortar  is  more 
important,  particularly  the  latter,  as  whenever  a  building  has  fallen 
from  using  poor  mortar  it  has  generally  been  on  account  of  the 
failure  of  the  mortar  to  adhere  to  the  bricks  or  stones.  Whatever 


CEMENT  MORTARS. 


195 


kind  of  mortar  is  used,  it  should  be  made  rich  and  well  worked,  as 
the  saving  by  using  more  sand  is  but  a  small  percentage  at  most, 
and  it  is  never  safe  for  an  architect  to  allow  poor  mortar  to  be 
used  in  his  buildings. 

The  safe  crushing  strength  of  Portland  cement,  natural  cement 
and  lime  mortar  used  in  ^-inch  joints  should  equal  the  following 
values  in  tons  per  square  foot : 

Portland  cement  mortar,  i  to  3,  3  months,  40  tons;  i  year,  65  tons. 
Natural        "  i  to  3,  3  months,  13  tons;  i  year,  26  tons. 

Lime  mortar  i  to  3,  3  months,  8.6  tons ;  i  year,  15  tons. 

From  these  values  we  see  that  for  granite  piers,  heavily  loaded, 
only  Portland  cement  mortar  should  be  used.  For  all  piers  loaded 
with  over  10  tons  per  square  foot,  and  not  exceeding  20  tons, 
natural  cement  mortar  may  be  used.  (See  also  Article  198,  "The 
Compressive  Strength  of  Cement  Mortars.") 

Lime  mortar  alone  should  never  be  used  where  any  but  moderate 
loads  are  to  bear  upon  the  work ;  nor  where  the  full  loading  is  to 
be  applied  before  the  mortar  has  had  time  to  harden. 

209.  THE  ADHESION  OF  MORTAR.— "The  adhesion  of 
mortars  to  brick  or  stone  varies  greatly  with  the  different  varieties 
of  these  materials,  and  particularly  with  their  porosity.  The 
adhesion  varies  also  with  the  quality  of  the  cement,  the  character, 
grain  and  quantity  of  the  sand,  the  amount  of  water  used  in  tem- 
pering, the  amount  of  moisture  in  the  stone  or  brick,  and  the  age 
of  the  mortar." 

Mortar  adheres  to  both  stone  and  brick  better  when  they  are  wet 
(unless  the  temperature  is  below  the  freezing  point),  and  the  archi- 
tect should  always  insist  on  having  the  bricks  well  wet  down  with 
a  hose  before  laying.  Dry  bricks  absorb  the  moisture  from  mortar 
so  that  it  cannot  harden  properly,  and  also  destroy  its  adhesive  prop- 
erties. The  wetting  of  the  bricks  is  fully  of  as  much  importance  as 
the  quality  of  the  mortar  in  the  brickwork.  The  adhesive  strengths 
of  cement  mortars  and  lime  mortars  are  as  a  rule  proportional  to  their 
tensile  strengths.  Therefore  where  great  adhesive  strength  is  required 
to  prevent  sliding,  as  in  arches,  etc.,  either  Portland  or  natural 
cement  should  be  used,  according  to  the  importance  of  the  work 
and  stress  to  be  resisted.  Some  years  ago  the  walls  of  a  brick 
building  in  New  York  City  were  pushed  outward  by  barrels  of 
flour  piled  against  them,  so  that  they  suddenly  fell  into  the  street. 
[An  examination  of  the  mortar  showed  that  it  was  of  poor  quality, 


196  BUILDING  CONSTRUCTION.  (Ch.  IV) 


with  little  adhesion  to  the  bricks.  If  good  mortar  had  been  used,  and 
if  the  bricks  had  been  well  wet,  the  failure  (it  should  not  be  called  an 
accident)  would  not  have  occurred.  The  adhesive  and  tensile 
strength  of  mortar  is  of  great  importance  also  in  resisting  wind 
pressure  and  vibration. 

210.  MORTAR  IMPERVIOUS  TO  WATER.— The  follow- 
ing proportions  may  be  used  for  making  a  water-tight  mortar,  pro- 
vided the  water  is  not  moving,  not  too  cold  and  not  impregnated 
with  acids : 

Cement.  Lime  Putty.  Sand. 

I  part.  part.  i  part. 

I  part.  I     part.  3  parts. 

I  part.  1V2  parts.  5  parts. 

I  part.  2     parts.  6  parts. 

A  frequent  cause  of  the  failure  of  masonry  is  the  disintegration  of 
the  mortar  in  the  outside  of  the  joints,  although  this  does  not  take 
place  to  such  an  extent  in  buildings  as  in  engineering  works.  "Or- 
dinary mortar,  either  lime  or  cement,  absorbs  water  freely,  com- 
mon lime  mortar  absorbing  from  50  to  60  per  cent  of  its  own 
weight,  and  the  best  Portland  cement  mortar  from  10  to  20  per 
cent,  and  consequently  they  disintegrate  under  the  action  of  the 
frost.  Mortar  may  be  made  practically  non-absorbent  by  the  addi- 
tion of  alum  and  potash  soap.  One  per  cent,  by  weight,  of  pow- 
dered alum  is  added  to  the  dry  cement  and  sand  and  thoroughly 
mixed,  and  about  i  per  cent  of  any  potash  soap  (ordinary  soft  soap 
made  from  wood  ashes  is  very  good)  is  dissolved  in  the  water  used 
in  making  the  mortar.  The  alum  and  soap  combine  and  form  com- 
pounds which  are  insoluble  in  water.  These  compounds  are  not 
acted  upon  by  the  carbonic  acid  of  the  air,  and  add  considerable  to 
the  early  strength  of  the  mortar  and  somewhat  to  its  ultimate 
strength."'''  The  alum  and  soap  are  comparatively  cheap  and  can 
be  easily  used.f 

The  mixture  could  be  advantageously  used  in  plastering  base- 
ment walls  and  on  the  outside  of  buildings,  and  would  add  greatly 
to  the  durability  of  mortar  used  for  pointing. 

211.  PLASTER  OF  PARIS  IN  MORTAR.— The  imperme- 
ability of  Portland  cement  mortar  is  increased  by  the  addition  of 
puzzolan  cement.    Plaster  of  Paris,  which  is  sulphate  of  lime,  when 


*  "Treatise  on  Masonry  Construction."    Ira  O.  Baker. 

t  For  the  effect  of  alum  and  soap  in  diminishing  the  permeability  of  mortars,  see  also 
results  of  experiments  by  Mr.  Edward  Cunningham,  and  Prof.  W.  K.  Hatt  in  Trans. 
Am.  Soc.  of  Civil  Engineers,  Vol.  LI,  pp.  127  and  128. 


CEMEXT  MORTARS.  197 

added  to  either  lime  or  cement  mortar  in  quantities  not  exceeding  5 
per  cent,  accelerates  the  setting  and  also  increases  the  early  and  the 
ultimate  strength  of  mortar.  Lime  mortar  to  which  plaster  of 
Paris  had  been  added  is  called  "gauged"  mortar.  Selenetic  lime, 
known  as  "Scott's  cement"  or  "Selenetic  cement,"  much  used  in 
England,  is  made  by  combining  plaster  of  Paris  and  hydraulic  lime, 
in  the  proportion  of  three  pints  of  the  plaster  to  a  bushel  of  un- 
slaked lime.  The  addition  of  the  plaster  of  Paris  to  lime  appears 
to  increase  the  strength  of  the  mortar  from  two  to  three  times. 

212.  SUGAR  IN  MORTAR.— Sugar  has  been  employed  for 
centuries  in  India  as  an  ingredient  of  common  lime  mortar,  and 
adds  greatly  to  the  strength  of  the  mortar. 

An  addition  of  sugar  or  syrup  equal  to  one-tenth  of  the  weight 
of  the  unslaked  lime,  to  lime  mortar,  adds  50  per  cent  to  the 
strength  of  the  mortar  and  will  cause  the  mortar  to  set  more  quickly. 
The  addition  of  sugar  to  lime  mortar  is  especially  beneficial  when 
used  in  very  thick  walls,  as  the  lime  mortar  thus  placed  is  never 
fully  acted  upon  by  the  carbonic  acid  of  the  atmosphere. 

Sugar  added  to  natural  and  Portland  cement  mortars  in  the 
proportion  of  3^  to  ^  per  cent  in  weight  of  the  cement  increases 
the  strength  of  the  mortars  about  25  per  cent. 

Experiments  made  to  determine  the  effect  of  sugar  upon  Port- 
land cement  showed  that  an  addition  of  from  j/g  to  2  per  cent  of 
sugar  added  to  Dyckerhoff's  German  Portland  cement  increased 
considerably  its  strength  after  three  months.  While  the  sugar 
retarded  the  setting,  and  favorably  assisted  the  perfecting  of  the 
chemical  changes,  more  than  2  per  cent  of  it  rendered  the  cement 
useless. 

As  the  combination  of  sugar  and  lime  is  soluble  in  water,  sugar 
should  not  be  added  to  mortar  that  is  to  be  used  under  water. 

Experiments  have  been  made  also  to  show  the  effect  on  the 
strength  and  other  properties  of  mortars  of  various  other  admix- 
tures, such  as  alcohol,  clay  and  loam,  glycerine,  lime,  peat,  plaster, 
salt,  sawdust,  soda,  tallow,  etc.* 

213.  EFFECT  OF  TEMPERATURE  ON  MORTARS.— 
Very  hot  weather  is  apt  to  injure  mortar  by  causing  its  water  to 
evaporate  too  rapidly,  and  thus  interfere  with  the  normal  setting 
or  hardening.    Stones  and  bricks  should  be  well  moistened  in  such 


*  For  a  short  bibliography  of  papers  relatiriP'  to  these  tests  see  "Concrete,  Plain  and 
Reinforced,"  Taylor  and  Thompson.    Chap.  XXIX,  "References  to  Concrete  Literature." 


198 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


weather  before  bedding  them  so  that  the  mortar  may  not  dry  out 
too  fast  and  be  reduced  to  a  powder  by  the  materials  absorbing  its 
moisture.  Freezing  does  not  appear  to  injure  Hme  mortar  if  the 
mortar  remains  frozen  until  it  has  fully  set.  Ahernate  freezing 
and  thawing  materially  damages  the  strength  and  adhesion  of  lime 
mortar,  and  as  this  is  generally  what  happens  when  mortar  is  laid 
in  freezing  weather,  it  is  much  the  safer  rule  for  the  architect  to 
specify  and  see  that  no  masonry  shall  be  laid  with  lime  mortar  at 
such  times. 

Very  cold  weather  retards  the  setting  or  hardening  of  cement 
mortar,  and  the  freezing  and  expansion  of  its  water  tend  to  disin- 
tegrate it.  If  the  temperature  of  mortar  can  be  kept  above  the 
freezing  point  long  enough  to  allow  it  to  set  with  sufficient  strength 
to  resist  the  disruptive  effect  of  frost,  it  may  be  used  in  freezing 
weather.  Quick-setting  Portlands  are  used,  or  hot  water,  or  salt 
put  in  the  water  used  in  making  the  mortar,  or  the  stones  or  bricks 
or  sand  additions  are  heated,  or  the  masonry  is  carefully  covered 
immediately  after  laying  with  straw  or  canvas  or  manure,  etc. 

Most  natural  cement  mortars  are  ruined  by  freezing.  They  ex- 
pand by  the  frost,  and  a  settlement  results  with  the  thawing. 

Portland  cement  mortars  have  their  setting  retarded,  and  their 
strength  at  short  periods  lowered,  by  freezing,  but  have  their  ulti- 
mate strength  but  slightly,  if  at  all,  affected. 

The  setting  of  cement  mortars  is  hastened,  and  the  action  of 
frost  retarded,  by  heating  the  materials. 

Salt  lowers  the  freezing  point  of  mortar,  and  does  not  seem  to 
affect  the  ultimate  strength  of  cement  mortar,  where  used  in  quan- 
tities up  to  10  per  cent  of  the  weight  of  the  water. 

"Mortar  composed  of  i  part  Portland  cement  and  3  parts  of  sand 
is  entirely  uninjured  by  freezing  and  thawing,  and  mortar  made  of 
.  natural  cement,  in  any  proportion,  is  entirely  ruined  by  freezing  and 
thawing."* 

214.  SALT  IN  MORTAR.— When  it  is  desfred  to  use  natural 
cement  mortar  in  freezing  weather  the  mortar  should  be  mixed 
with  water  to  which  salt  has  been  added  in  the  proportion  of  one 
pound  of  salt  to  eighteen  gallons  of  water,  when  the  temperature 
is  at  32  degrees  Fahr.,  and  for  each  degree  of  temperature  below 
32  degrees  add  three  additional  ounces  of  salt.    Mortar  mixed  with 


*  Trans.  Am.  Soc.  of  C.  E.,  Vol.  XVI.,  pp.  79-84. 


MORTAR  COLORS  AND  STAINS.  199 

such  a  solution  does  not  freeze  in  ordinary  winter  weather,  and 
hence  is  not  injured  by  frost. 

Builders  sometimes  advocate  the  addition  of  hme  to  natural 
cement  mortars  in  cold  weather  to  ^ivarm  them.  There  would  be  no 
heating  effect  of  the  lime,  however,  as  heat  is  generated  in  lime  only 
when  it  slakes.  If  natural  cement  mortars  must  be  used  in  freezing 
weather,  the  only  safe  way  of  using  them  is  by  the  addition  of  salt, 
as  described  on  opposite  page,  otherwise  the  mortars  will  be  com- 
pletely ruined  by  freezing. 

215.  CHANGE  OF  VOLUME  IN  SETTING.— Cement  mor- 
tars diminish  slightly  in  volume  during  the  early  periods  of  setting 
in  air,  and  expand  in  like  manner  but  in  a  less  degree  when  under 
water,  but  the  expansion  and  contraction  are  not  sufficient  to  injuri- 
ously affect  building  construction.  The  contractions  and  expan- 
sions are  greatest  in  neat  cement  mortars. 

8.    MORTAR  COLORS  AND  STAINS. 

216.  THE  USE  OF  MORTAR  COLORS.— The  natural  color 
of  the  cement,  sand  and  stone  or  gravel  used  affects  the  color  of  a 
mortar  or  concrete,  and  these  separate  ingredients  of  the  complex 
mixture  also  modify  the  final  shades  even  after  the  addition  of 
coloring  matters. 

Mortars  and  concretes  of  different  shades  can  be  made  by  vary- 
ing the  amount  of  water  used. 

Sands  of  different  colors  give  different  final  colors  to  mortars 
and  concretes,  the  color  of  the  other  ingredients  remaining  the 
same ;  and  the  results  obtained  in  this  manner  are  usually  far  more 
permanent  and  satisfactory  than  those  obtained  from  the  use  of 
artificial  coloring  matters. 

The  use  of  artificial  coloring  in  mortars,  however,  has  been  in 
vogue,  more  or  less,  for  two  thousand  years,  but  the  general  use 
of  colored  mortars  dates  from  a  comparatively  recent  period. 

The  object  aimed  at  in  using  colored  mortars  in  brickwork  or 
stonework  is  either  to  get  the  effect  of  a  mass  of  color,  by  conceal- 
ing the  joints,  or  else,  by  using  a  contrasting  color,  to  emphasize 
the  joints.  Rougher  bricks  may  also  be  used  with  nearly  as  good 
effect  by  using  a  mortar  of  the  same  color  as  the  bricks.  Chipped 
or  uneven  edges  -do  not  show  as  plainly  with  mortar  of  the  same 
color  as  the  bricks  as  they  do  when  laid  with  white  mortar. 

Coloring  matter  is  added  also  to  cement  and  concrete  surfaces  of 


200  BUILDIXG  COXSTRUCTION.  (Ch.  IV) 


all  kinds,  either  to  obtain  a  color  effect  in  the  cement  in  concrete  itself, 
or  to  imitate  stone  of  various  kinds. 
I       217.    OBJECTIONS  TO  MORTAR  COLORS.— The  objec- 
tion is  sometimes  made  to  the  use  of  colored  mortars  that  they  are 
not  as  strong  as  white  mortars  and  that  the  color  always  fades. 

These  objections  undoubtedly  have  much  truth  in  them  when 
cheap  colors  are  used  and  the  mortar  is  not  properly  mixed,  but 
there  are  better  grades  of  mortar  colors  now  on  the  market  which 
affect  the  strength  of  the  mortar  to  a  very  slight  extent,  and  some 
of  them,  when  properly  mixed,  hold  their  color  fairly  well. 

218.  KINDS  OF  COLORS.— Most,  if  not  all,  of  the  coloring 
materials  sold  under  the  name  of  ''mortar  colors,"  or  stains,  consist 
of  mineral  pigments  put  up  either  in  the  form  of  a  dry  powder  or 
in  the  form  of  a  pulp  or  paste. 

Pulp  colors  are  thought  by  some  to  lend  themselves  more  readily 
than  the  dry  colors  to  a  uniform  mixing  with  the  mortar,  and  they 
are  sometimes  preferred  for  the  better  grades  of  work. 

Paste  or  pulp  stains  should  not  be  allowed  to  freeze,  and  should 
be  kept  moist  by  covering  with  water. 

A  great  deal  of  colored  mortar  is  made  by  using  common  lamp- 
black and  Venetian  red,  or  the  cheap  grades  of  mineral  paints  for 
the  coloring  matter.  These  are  very  apt  to  fade  and  run  and  also 
tend  to  weaken  the  mortar,  and  the  cheaper  grades  of  mineral  colors 
are  not  much  better.  Red  lead,  for  example,  is  said  to  be  injurious, 
even  in  very  small  quantities.  The  cost  of  the  coloring  matter  is  so 
small  an  item  that  only  the  very  best  grades  should  be  used. 

The  principal  colors  used  are  red,  brown,  buff  and  black,  although 
green,  purple,  gray,  drab  and  other  mortar  colors  are  made. 

For  different  grades  of  gray  the  proper  kind  of  lampblack  is  used 
in  varying  proportions. 

The  proportions  used  for  the  dry  mineral  colors  vary  from  2  to 
10  per  cent  of  the  amount  of  cement,  according  to  the  shade  desired. 

No  injurious  effects  appear  to  result  from  the  use  of  Prussian 
blue,  ultramarine  blue  (in  small  quantities),  burnt  umber,  red  iron 
ore,  yellow  ochre  and  boneblack  lampblack. 

Among  the  lampblacks  the  ''Germantown  lampblack"  is  consid- 
ered a  desirable  coloring-  material,  on  account  of  the  small  quan- 
tities necessary  to  obtain  a  good  color.    It  is  stated  that  even  as 
,  small  an  amount  as  i  per  cent  of  red  lead  works  more  or  less  injury 


MORTAR  COLORS  AND  STAINS. 


20 1 


to  cement  mortar  and  concrete,  and  that  it  is  not  advisable  to  use 
it  in  larger  amounts. 

Only  moderate  quantities  of  colors  other  than  those  mentioned 
should  be  used. 

Red  oxide  of  iron,  if  it  contains  sulphuric  acid,  may  cause  swell- 
ing. Peroxide  of  manganese  is  sometimes  used  to  produce  shades 
of  black  and  bluish  gray ;  the  best  raw  iron  oxide  to  produce  red ; 
caput  mortuum  (expensive)  to  produce  bright  red;  Venetian  red 
Xo  produce  a  cheaper  red ;  the  best  roasted  iron  oxide  to  produce 
brown ;  and  ochre  to  produce  buff. 

The  following  are  useful  data'''  compiled  by  Mr.  Charles  Carroll 
Brown,  and  bearing  upon  this  subject: 

"Cement  manufacturers  recommend  the  following  quantities  per 
100  pounds  of  cement : 

Black,  2  pounds  excelsior  carbon  black. 

Blue,  5  to  6  pounds  ultramarine. 

Brown,  6  pounds  roasted  iron  oxide. 

Gray,  ^  pound  lampblack. 

Green,  6  pounds  ultramarine. 

Red,  6  to  10  pounds  raw  iron  oxide. 

Bright  red,  6  pounds  Pompeiian  red. 

Yellow  or  bu0,  6  to  10  pounds  yellow  ochre. 

"It  is  said  that  unfading  colored  cement  can  be  made  by  mixing 
with  the  raw  materials  before  burning  chromic  oxide  for  green, 
oxide  of  copper  for  a  blue-green,  and  equal  parts  of  oxides  of  iron, 
manganese  and  cobalt  for  a  black  color.  Such  cements  are  not  on 
the  general  market,  however.  Finely  ground  oxide  of  manganese 
added  to  the  mortar  will  give  a  black  color  and  not  weaken  the 
concrete.    Venetian  red  and  lampblack  will  fade. 

"White  cements  are  often  asked  for.  There  is  some  difference  in 
shade  of  Portland  cements  and  puzzolan  cements  are  usually  the 
lightest.  They  are  not  satisfactory  for  greatly  exposed  work..  An 
English  patent  makes  a  white  cement  by  mixing  one  part  of  kaolin, 
a  clay  without  iron,  three  to  five  parts  of  white  chalk,  and  two  to 
five  per  cent  of  gypsum,  or  three  to  five  per  cent  of  magnesium 
chloride.  The  mixture  is  burned  as  any  other  cement  is  burned. 
The  resulting  cement  would  probably  not  stand  severe  exposure  to 
the  weather.    Lafarge,  a  French  "grappier"  cement,  is  very  light 


*  "Handbook  for  Cement  Users."  Edited  by  Charles  Carroll  Bro\^m.  Published  by 
Municipal  Engineering  Company,  Indianapolis  and  New  York. 


202 


BUILDING  CONSTRUCTION. 


(Ch.  IV) 


colored.  The  use  of  a  white  marble  dust  in  place  of  sand  and  puz- 
zolan  or  lighter  cements  produces  the  best  results  yet  obtained.  Sul- 
phate of  barium,  oxide  of  zinc  and  sulphate  of  lead  produce  a 
grayish  white  color,  but  their  permanence  is  not  guaranteed." 

The  following  table*  is  given  by  Mr.  Lewis  Carlton  Sabin,  and 
shows  the  colors  given  to  Portland  cement  mortar  containing  two 
parts  yellow  river  sand  to  one  part  cement. 


TABLE  XVL 
Colors  for  Portland  Cement  Mortars. 


Cost  of 
Coloring  Matter 
per  lb.  ct. 

Dry 
material 
used 

Weight  of  Dry  Coloriijg  Matter  to  100  Pounds  of  Cement 

^  pound 

I  pound 

2  pounds 

4  pounds 

15 

Lamp 

Light 

Light 

Blue 

Dark  Blue 

Black 

Slate 

Gray 

Gray 

Slate 

50 

Prussian 

Light  Green 

Light  Blue 

Blue 

Bright  Blue 

Blue 

Slate 

Slate 

Slate 

Slate 

20 

Ultramarine 

Light  Blue 

Blue 

Bright  Blue 

Blue 

Slate 

Slate 

Slate 

3 

Yellow 

Light 

Light 

Ochre 

Green 

•  Buff 

10 

Burnt 

Light  Pinkish 

Pinkish 

Dull  Laven- 

Chocolate 

Umber 

Slate 

Slate 

der  Pink 

Venetian 

Slate, 

Bright 

•  Light 

Dull 

Red 

Pink  Tinge 

Pinkish  Slate 

Dull  Pink 

Pink 

2 

Chattanooga 

Light  Pinkish 

Dull 

Light 

Light 

Iron  Ore 

Slate 

Pink 

Terra-Cotta 

Brick  Red 

Red  Iron 

Pinkish 

Dull 

Terra- 

Light 

Ore 

Slate 

Pink 

cotta 

Brick  Red 

Mr.  Homer  A.  Reid  has  compiled  a  listf  of  the  usual  proportions 
by  weight  of  different  coloring  matters  to  be  added  to  i  sack  of 
cement  and  2  cubic  feet  of  sand  (a  i  to  2  mixture)  to  secure  dif- 
ferent colored  mortars. 

The  list  gives  the  weight  of  coloring  matter  to  i  sack  of  cement 
for  a  I  to  2  mixture,  and  is  as  follows : 

FOR  WHITE  STONE: 

White  Portland  cement,  i  part; 
Pulverized  lime,  54  part;  # 
Pulverized  marble,  part; 
Light-colored  sand,  i  part. 

On  account  of  the  inferiority  of  white  Portland  cement,  the  above  is 
seldom  used. 

*  "Cement  and  Concrete."     Lewis  Carlton  Sabin. 

+  "Concrete,  and  Reinforced  Concrete  Construction."    Homer  A.  Reid. 


MORTAR  COLORS  AND  STAINS. 


FOR  BLACK  STONE: 

3  lbs.  Excelsior  carbon  black,  or 

II  lbs.  manganese  dioxide. 
GRAY  STONE: 

I  lb.  Excelsior  carbon  black,  or 

^  lb.  Germantown  lampblack  (boneblack). 
BROWN  STONE: 

4  to  5  lbs.  brown  ochre,  or 

6  lbs.  roasted  iron  oxide,  best  quality. 
BUFF  STONE: 

4  lbs.  yellow  ochre. 
RED  STONE: 

5  lbs.  violet  iron  oxide  (raw). 
BRIGHT  RED  STONE: 

From  5^  to  7  lbs.  English  or  Pompeiian  red. 
YELLOW  STONE: 

5>4  lbs.  ochre. 
GREEN  STONE: 

6  lbs.  of  greenish  blue  ultramarine  blue. 
BLUE  STONE: 

2  lbs.  ultramarine  blue. 
DARK  BLUE  STONE: 

4  lbs.  ultramarine  blue. 
PURPLE  STONE: 

5  lbs.  Prince's  metallic. 
VIOLET  STONE: 

5^  lbs.  violet  oxide  of  iron. 
In  the  construction  of  six  emplacements  at  Fort  Wadsworth, 
New  York,  the  exterior  surface  was  coated  with  colored  mortar 
mixed  according  to  the  following  formulas: 
FOR  GREEN  COLOR: 

Cement,  i  bbl. ; 

Sand,  2  bbls. ; 

Ultramarine  blue,  50  lbs.; 

Yellow  ochre,  73  lbs. ; 

Soft  soap,  7  lbs. ; 

Alum,  7  lbs. 
FOR  SLATE  COLOR: 

Cement,  i  bbl.; 

Sand,  2  bbls. ; 

Lampblack,  50  lbs. ; 

Ultramarine  blue,  35  lbs.; 

Soft  soap,  7  lbs. ; 

Alum,  7  lbs. 

After  completion  of  the  batteries,  the  color  became  much  lighter 
with  age.  It  was  found  that  spraying  with  linseed  oil  very  materi- 
ally deepened  its  shade. 


204 


BUILDING  CONSTRUCTION.  (Ch.  IV) 


219.  MIXING. — Mortar  colors,  whether  in  dry  or  paste  form, 
should  not  be  mixed  with  lime  until  the  latter  has  been  slaked  at 
least  forty-eight  hours,  and  the  best  way  is  to  keep  a  lot  of  lime 
putty  on  hand  and  mix  the  color  with  it  as  needed.  Mortar  colors 
should  never  be  mixed  with  hot  lime. 

For  coloring  lime  mortar  the  colors  should  first  be  mixed  with 
dry  sand,  then  the  cold  slaked  lime  added  and  again  mixed  thor- 
oughly.   It  is  very  important  that  the  colors  be  uniformly  mixed. 

For  cement  and  concrete  work  the  stain  should  be  thoroughly 
mixed  with  the  cement,  the  sand  then  added,  and  the  whole  thor- 
oughly mixed  dry.  When  gravel  or  stone  is  used  it  should  be  mixed 
dry  with  the  sand  and  coloring  matter,  and  then  the  whole  should 
be  thoroughly  mixed  until  the  color  of  the  mass  is  uniform.  After 
this  the  water  should  be  gradually  added  as  needed,  and  the  mixing 
continued  until  the  requisite  consistency  is  obtained. 

The  color  of  the  mortar  looks  different  in  the  bed  than  when  dry. 
To  get  the  final  color  of  the  mortar  a  little  should  be  taken  from 
the  bed  and  permitted  to  dry  thoroughly,  when  the  permanent  color 
may  be  seen.   The  gloss  of  the  water  makes  the  mortar  look  darker. 

The  amount  of  coloring  matter  required  to  stain  a  given  quantity 
of  mortar  varies  with  the  different  colors  and  brands.  The  follow- 
ing quantities  may  be  taken  as  the  average  amounts  required  in 
laying  one  thousand  bricks  with  spread  joints: 

Red,  buff  or  brown,  50  pounds. 

Black,  from  40  to  45  pounds. 

When  buttered  joints  are  used: 

Red,  buff  or  brown,  40  pounds. 

Black,  from  25  to  35  pounds. 

The  following  additional  data*  give  the  weight  of  coloring  matter 
to  I  barrel  of  cement,  advised  by  good  authorities : 

GRAY,  use  2  pounds  of  Germantown  lampblack  to  a  barrel  of  cement. 
BLACK,  use  45  pounds  of  manganese  dioxide  to  a  barrel  of  cement, 
BLUE,  use  19  pounds  of  ultramarine  to  a  barrel  of  cement. 
GREEN,  use  23  pounds  of  ultramarine  to  a  barrel  of  cement. 
RED,  use  22  pounds  of  iron  oxide  to  a  barrel  of  cement. 
BRIGHT  RED,  use  22  pounds  of  Pompeiian  or  English  red  to  a  barrel 
of  cement. 

VIOLET,  use  violet  oxide  of  iron  22  pounds  to  a  barrel  of  cement. 
YELLOW  and  BROWN,  use  22  pounds  of  ochre  to  a  barrel  of  cement. 


*  "Handbook  for   Superintendents   of   Construction."    H.    G.  Richey. 


Chapter  V. 


Building-  Stones. 


I.  INTRODUCTORY. 

220.  THE  SUBJECT  IN  GENERAL.— It  is  important  that  an 
architect  should  have  some  knowledge  of  the  nature  of  the  different 
kinds  of  stone  in  order  that  he  may  know  what  kind  it  is  best  to 
use  or  not  to  use  under  any  given  circumstances.  While  he  is  not 
expected  to  possess  the  special  knowledge  of  a  geologist,  a  mineral- 
ogist or  a  chemist,  nor  to  determine  the  exact  composition  of  a 
stone,  he  is  supposed  to  know  enough  of  the  subject  to  specify 
stones  which  jiave  sufficient  strength  and  durability,  and  which  will 
not  become  discolored  by  chemical  changes  in  their  constituents. 

This  general  knowledge  of  building  stones  requires  not  only  a 
study  of  their  mineral  constituents  and  of  their  structure,  but  alsa 
much  accurate  observation  and  experience. 

221.  PRODUCTION  AND  VALUE  OF  DIFFERENT 
KINDS  OF  STONE.— The  following  table*  shows  the  value  of 
the  different  kinds  of  stone  produced  in  the  United  States  from 
1896  to  1906,  inclusive : 

TABLE  XVII. 

Value  of  the  Different  Kinds  of  Stone  Produced  in  the 
United  States,  1896- 1906. 


Year 


1900. 

1903. 
1904. 
1905. 

1906. 


Granite  Trap  rock  Sandstone  Bluestone    Marble   Limestone  Total 


$7,944,994 
8,905,075 
9,324,406 
10,343,298 
10.969,417 

14,266,104 
16,083.475 
15,703,793 
17,191,479 
17,563,139 

18,569,705 


$1,275,041 
1,706,200 

1,710,857 
2,181,157 
2,732,294 
2,823,546 
3,074,554 

3,736,571 


$4,023,199 
4,065,445 
4,724,412 
^4,910,111 
45,272,865 

46,974,199 
49,430.958 
49,482,802 
48,482,162 
48,075,149 

47,147,439 


^$750,000 
<a900,000 
^1,000,000 
815,284 
1,198,519 

1,164,481 
1,163,525 
1,779,457 
1,791,729 
1,931,625 

2,021,898 


$2,859,136 
3,870,584 
3,629,940 
4,011,681 
4,267,253 

4,965,699 
5,044,182 
5,362,686 
6,297,835 
7,129,071 

7,583,938 


$8,387,900 
9,135,567 
9,956,417 
13,889,302 
13,556,523 

18,202,843 
20,895,385 
23,372,109 
22,178,964 
26,025,210 

27,320,243 


$23,965,229 
26,876,671 
28,635,175 
35,244.717 
30,970,777 

47,284,183 
54,798,68^ 
57,433,141 
58,765,715 
63,798,748 

66,378,794 


a  Estimated 


4  Does  not  include  the  value  of  grindstones  and  whetstones. 


*  Mineral  Resources  of  the  United  States  for  1906.  Article  on  "Stone,"  by  A.  T. 
Coons. 


205 


-206 


BUILDING  CONSTRUCTION. 


(Ch.V) 


The  table  shows  that  the  total  reported  value  of  stone  quarried  in 
the  United  States  in  1906,  exclusive  of  products  mentioned  on  pre- 
ceding page,  was  $66,378,794.  The  corresponding  value  for  1905 
was  $63,798,748,  an  increase  for  1906  of  $2,580,046.  In  1905  the 
gain  was  $5,033,033;  in  1904  it  was  only  $1,332,574;  in  1903  it  was 
$2,634,459,  and  in  1902  it  was  $7,514,499.  The  increase  for  1906 
over  1896  is  $42,413,565.  The  production  of  1902,  1903,  1904  and 
1905  was  affected  by  strikes  in  the  building  trades,  but  continued 
increase  in  the  production  of  crushed  stone  and,  in  1905,  of  stone 
for  furnace  flux  caused  increased  values  in  the  totals.  In  1906 
almost  all  the  producers,  and  especially  the  small  quarrymen,  stated 
that  the  cost  of  production  had  increased  on  account  of  increased 
cost  of  supplies,  high  wages  and  lack  of  common  labor ;  and  that 
less  stone  was  produced  on  account  of  the  cheaper  production  and 
increased  use  of  concrete,  cement  and  concrete  blocks. 

Granite,  trap  rock,  marble,  bluestone  and  limestone  increased  in 
value,  while  the  value  of  sandstone  decreased. 

Granite,  trap  rock,  etc.,  represented  33.60  per  cent  of  the  total 
output  in  1906,  and  increased  in  value  from  $20,637,693  in  1905  to 
$22,306,276  in  1906,  a  gain  of  $1,668,583.  Trap  rock  increased  in 
value  from  $3,074,554  in  1905  to  $3,736,571  in  1906,  or  $662,017. 
Granite  increased  from  $17,563,139  in  1905  to  $18,569,705  in  1906, 
a  gain  of  $1,006,566. 

Sandstone  and  bluestone  represented  13.80  per  cent  of  the  total 
stone  output  in  1906.  Their  value  in  1906  was  $9,169,337,  which, 
compared  with  a  value  of  $10,006,774  in  1905,  shows  a  decrease  of 
$837,437.  Bluestone  increased  in  value  from  $1,931,625  in  1905 
to  $2,021,898  in  1906,  a  gain  of  $90,273.  Sandstone  decreased  in 
value  from  $8,075,149  in  1905  to  $7,147,439  in  1906,  a  loss  of 
$927,710. 

Marble  represented  11.42  per  cent  of  the  total  stone  output  in 
1906,  the  total  value  being  $7,582,938;  in  1905  the  value  was 
$7,129,071,  a  gain  for  1906  of  $453,867.  ^ 

Limestone  represented  41.16  per  cent  of  the  total  stone  output  of 
the  United  States  in  1906,  and  was  valued  at  $27,320,243 ;  in  1905 
the  value  was  $26,025,210,  a  gain  for  1906  of  $1,295,033. 

222.  GOVERNMENT  CLASSIFICATION  IN  STONE  PRO- 
DUCTION.— For  simplicity  of  treatment  the  kinds  of  stone  covered 
by  the  figures  given  are  classified  as  granite,  trap  rock,  sandstone, 
bluestone,  limestone  and  marble. 


BUILDING  STONES— INTRODUCTORY. 


207 


Granite  includes  true  granites  and  other  igneous  rocks,  as  gneiss, 
mica  schist,  andesite,  syenite,  trachyte,  quartz  porphyry,  lava,  tufa, 
diabase,  trap  rock,  basalt,  diorite,  gabbro,  and  a  small  quantity  of 
serpentine.  Rocks  of  these  kinds  are  as  a  rule  quarried  commer- 
cially in  quantities  too  small  to  permit  their  being  tabulated  sepa- 
rately, but  the  trap  rock  output  of  California,  Connecticut,  Massa- 
chusetts, New  York,  New  Jersey  and  Pennsylvania  represents  an 
important  industry,  and  it  is  therefore  considered  advisable  to  show 
the  value  of  this  stone  separately.  The  trap  rock  from  California 
includes  a  considerable  quantity  of  basalt. 

Sandstone  includes  the  quartzites  of  South  Dakota  and  Minnesota, 
but  the  fine-grained  sandstones  of  New  York  and  Pennsylvania, 
known  to  the  trade  as  bluestone,  are  the  product  of  a  separate  indus- 
try, and  their  production  is  shown  apart  from  that  of  the  other 
sandstone.  This  bluestone  is  also  quarried  in  New  Jersey  and  West 
Virginia.  In  Kentucky  most  of  the  sandstone  quarried  and  sold  is 
known  locally  as  freestone.  The  figures  given  for  sandstone  do  not 
include  the  value  of  the  grindstones,  whetstones  and  pulpstones, 
made  from  sandstone  quarried  in  Michigan,  Ohio  and  West  Vir- 
ginia. Neither  does  the  total  sandstone  value  include  sandstone 
crushed  into  sand  and  used  in  the  manufacture  of  glass  and  as  mold- 
ing sand. 

Limestone  does  not  include  limestone  burned  into  lime,  bituminous 
limestone,  nor  limestone  entering  into  the  manufacture  of  Portland 
cement.  It  includes,  however,  a  small  quantity  of  stone  sold  locally 
as  marble. 

Marble  includes  a  small  quantity  of  serpentine  quarried  and  sold 
as  marble  in  Georgia,  Washington  and  Pennsylvania. 

The  values  given  represent  the  net  value  of  the  stone  to  the  quarry- 
men,  that  is,  the  selling  value  exclusive  of  any  freight  charges. 
When  the  stone  is  cut  or  dressed  by  the  quarrymen  and  sold  in  this 
manner,  the  value  of  the  dressed  stone  is  given.  This  applies  espe- 
cially to  the  stone  quarried  for  use  as  building  and  monumental 
stone.  The  value  of  crushed  stone  is  the  net  value  crushed  at  the 
point  of  shipment. 

223.  RANK  OF  STATES  AND  TERRITORIES  IN 
VALUE  OF  STONE  PRODUCTION.— In  the  Appendix  are 
given  tables  showing  the  value  of  the  various  kinds  of  stone  pro- 
duced in  1905  and  1906,  by  States  and  territories,  and  a  table 
showing  the  rank  of  the   States   and   territories   in   these  years. 


2o8 


BUILDIXG  COXSTRUCTION. 


(Ch.V) 


according  to  value  of  production,  and  the  percentage  of  the  total 
produced  by  each  State  or  territory. 

From  this  latter  table  it  is  seen  that  Pennsylvania,  producing 
chiefly  limestone  and  .  sandstone  but  also  granite  and  marble, 
reported  the  greatest  value  of  stone  output  for  the  entire  United 
States,  which  was  13.27  per  cent  of  the  total  ;  Vermont,  producing 
granite,  marble  and  a  small  quantity  of  limestone,  was  second,  with 
11.34  per  cent  of  the  total;  New  York,  producing  sandstone,  lime- 
stone, granite  and  marble,  ranked  third ;  Ohio,  producing  lime- 
stone and  sandstone,  was  fourth ;  Massachusetts,  producing  granite, 
marble,  sandstone  and  limestone,  was  fifth ;  Indiana  was  sixth, 
followed  by  Illinois,  Maine,  California  and  Missouri,  each  pro- 
ducing stone  valr-^d  at  over  $2,000,000. 

224.  TOTAL  VALUE  OF  STONE  USED  FOR  VARIOUS 
PURPOSES. — The  following  table  is  given  to  show  the  total 
values  of  the  stone  used  for  various  purposes  in  'I905  and  1906; 
only  those  values  are  given  which  are  for  uses  common  to  two  or 
more  varieties  of  stone ; 

TABLE  XVIIL 

Value  of  Granite,  Sandstone,  Limestone;  and  Marble  Used 
FOR  Various  Purposes  in  1905  and  1906. 


Kind 


Granite . . . 
Sandstone 
Limestone 
Marble ... . 

Total. 


Building 
(rough  and 
dressed) 

Monumental 
(rough  and 
dressed) 

Flagstone 

Curbstone 

Paving 
stone 

Crushed 
stone 

$7,298,797 
4,702,189 
5.312,183 
2,927,640 

$3,842,368 
2,270,217 

$38,838 
1,221,348 
127,801 

$2,133,873 
716,682 
231,785 

$4,923,706 
1,008,2:0 
10,487,638 

120,240,809 

$6,112,585 

$1,387,987 

$2,090,839 

$3,082,340 

$16,419,614 

$8,536,420 
4,275,669 
5,092.916 
2,782,620 

$4,116,075 
2,657,813 

$20,687,625 

$6,773,888 

Granite . . . 
Sandstone 
Limestone 
Marble . . . . 

Total. 


$50,609 
[,097,438 
109,632 


$1,257,679 


$787,237 
1,074,369 
289,615 


$2,151,221 


$1,652,927 
694,995 
531,275 


$2,879,197 


From  this  table  it  appears  that  the  total  value  of  building  stone 
increased  from  $20,240,809  in  1905  to  $20,687,625  in  1906,  a  gain 
of  $446,816.    Granite  represented  in  1906  41.26  per  cent  of  this 


BUILDIXG  STOXES—IXTRODUCTORY. 


building  stone ;  limestone,  24.62  per  cent ;  sandstone,  20,67  P^^  cent  ; 
and  marble,  1345  per  cent. 

Monumental  stone  increased  in  value  from  $6,112,585  in  1905  to 
$6,773,888  in  1906,  a  gain  of  $661,303.  Of  the  monumental  stone 
60.76  per  cent  was  granite  in  1906  and  39.24  per  cent  marble. 

Flagstone  in  1906  decreased  in  value  $130,308,  or  from  $1,387,987 
in  1905  to  $1,257,679  in  1906.  Sandstone  represented  87.26  per 
cent  of  the  flagstone  output  in  1906,  The  proportion  of  granite  and 
limestone  was  small. 

Curbstone  increased  in  value  from  $2,090,839  in  1905  to 
$2,151,221  in  1906,  or  $60,382.  Sandstone  represented  49.94  per 
cent  of  this  output  in  1906 ;  granite,  36.60  per  cent ;  and  limestone, 
13.46  per  cent. 

Paving  stone  decreased  in  value  from  $3,082,340  in  1905  to 
$2,879,197  in  1906,  a  loss  of  $203,143.  Granite  was  57.40  per  cent 
of  the  total  paving  material;  sandstone,  24.14  per  cent;  and  lime- 
stone, 18.46  per  cent. 

225.  DISTRIBUTION  OF  BUILDING  STONES  IN  THE 
UNITED  STATES. — A  general  consideration  of  the  geographi- 
cal distribution  of  stones  of  various  kinds  throughout  the  United 
States  is  of  interest  and  importance  in  the  study  of  building  stones. 

The  following  table*  illustrates  this  distribution  and  the  conse- 
quent resources  of  the  various  States,  and  mentions  only  those 
stones  ''which  it  seemed  safe  to  assume  occur  in  such  quantities  or 
under  such  conditions  as  to  render  them  of  present  or  prospective 
value  for  the  purposes  under  discussion.  For  the  purpose  of  easy 
reference,  the  States  are*  arranged  alphabetically.  A  name  in 
italics  indicates  that  the  stone  is,  or  has  been,  actively  quarried 
within  a  comparatively  recent  period." 

TABLE  XIX. 

Distribution  of  Building  Stones  in  the  United  States. 

State  or  Territory.  Present  and  Prospective  Resources. 

Alabama   Marble,  limestone,  granite,  sandstone. 

Arizona  Onyx  marble,  limestone,  granite,  trappean  and  vol- 
canic rocks,  and  sandstones. 
Arkansas   Marble,  limestone,  syenite. 

California   Serpentine  (verdantique  marble),  onyx  marble,  mar- 
ble, limestone,  granite,  volcanic  rocks  and  tuffs, 
sandstone,  slate. 

*  "Stones  for  Building  and  Decoration,"  by  George  P.  Merrill.  John  Wiley  Sons, 
New  York,  1903. 


2IO 


9 

BUILDING  CONSTRUCTION. 


(Ch.  V) 


TABLE  XIX  (Continued). 


Colorado   Marble,   limestone,  granite,  trappean  and  volcanic 

rocks,  sandstone,  quartsite,  rhyolite  tiiif. 

Connecticut   Soapstone,  serpentine  (verdantique  marble),  marble, 

granite  and  gneiss,  diabase,  sandstone. 

Delaware   Marble,  gneiss. 

Florida  Shell  and  oolitic  limestone. 

Georgia  . .  Marble,  granite,  gneiss,  sandstone,  slate. 

Idaho   Limestone,  marble,  granite,  trappean  and  volcanic 

»  rocks,  sandstone. 

Illinois   Limestone  and  dolomite,  sandstone. 

Indiana  Limestone,  dolomite,  sandstone. 

Indian  Territory  Limestone,  dolomite,  sandstone. 

Iowa   Gypsum,  limestone,  dolomite,  sandstone. 

Kansas   Limestone,  dolomite,  sandstone. 

Kentucky   Limestone,  dolomite,  sandstone. 

Louisiana   Limestone,  sandstone. 

Maine   Soapstone,  serpentine  (verdantique  marble),  lime- 
stone, granite,  gneiss,  diabase,  norite,  gabbro, 
quartz,  porphyry,  sandstone,  slate. 

Maryland   Soapstone,  serpentine  {verdantique  marble),  marble, 

granite,  sandstone,  slate. 

Massachusetts   Soapstone,  serpentine  {verdantique  marble),  marble, 

granite,  gneiss,  quartz  porphyry. 

Michigan   Limestone,  dolomite,  granite,  gneiss,  sandstone,  slate. 

Minnesota   Limestone,  dolomite,  granite,  gneiss,  sandstone,  slate. 

Mississippi   Limestone,  sandstone. 

Missouri   Limestone,  dolomite,  granite,  diabase,  quartz  por- 
phyry, sandstone. 

Montana   Limestone,  dolomite,  granite,  gneiss,  trappean  and 

volcanic  rocks,  sandstone. 
Nebraska   Limestone,  dolomite,  sandstone. 

Nevada   Limestone,  dolomite,  granite,  trappean  and  volcanic 

rocks,  sandstone. 

New  Hampshire  Soapstone,  limestone,  granite,  slate. 

New  Jersey  Serpentine,    limestone,    dolomite,    marble,  granite, 

gneiss,  diabase,  sandstone,  slate. 

New  Mexico  Serpentine    {riccolite) ,  limestone,   marble,  trappean 

and  volcanic  rocks,  sandstone,  granite. 

New  York  Soapstone,  serpentine  {verdantique  marble),  lime- 
stone, dolomite,  marble,  granite,  gneiss,  norite, 
sandstone,  slate. 

■* 

North  Carolina  Soapstone,  serpentine,  limestone,  dolomite,  marble, 

granite,  gneiss,  diabase,  norite,  sandstone. 

North  Dakota  Limestone,  dolomite,  sandstone. 

Ohio   Limestone,  dolomite,  sandstone. 

Oklahoma   Limestone,  dolomite,  sandstone. 


BUILDING  STOXES— INTRODUCTORY. 


211 


TABLE  XIX  (Coiitiniicd). 


Oregon   Limestone,  dolomite,  granite,  trappcan  and  volcanic 

rocks,  sandstone. 

Pennsylvania   Soapstone,  serpentine,  limestone,  dolomite,  marble, 

granite,  gneiss,  diabase,  quartz  porphyry,  sand- 
stone,  conglomerate,  slate. 

Rhode  Island  Limestone,  dolomite,  granite,  gneiss. 

South  Carolina  Limestone,  granite,  gneiss. 

South  Dakota  Limestone,  sandstone,  quartzite. 

Tennessee   Limestone,  marble,  granite,  diorite,  sandstone. 

Texas   Limestone,  marble,  grani-tc,  trappean  and  volcanic 

rocks,  sandstone. 

Utah   Limestone,  marble,  granite,  trappean  and  volcanic 

rocks,  sandstone. 

Vermont   Soapstone,  serpentine  (verdantique  marble),  marble, 

gneiss,  slate. 

Virginia   Soapstone,  limestone,  marble,  granite,  gneiss,  diabase, 

granite,  gneiss,  slate. 

Washington   Limestone,  marble,  granite,  trappean  and  volcanic 

rocks,  sandstone. 
West  Virginia   Limestone,  sandstone. 

Wisconsin   Dolomite,  granite,  gneiss,  quartz  porphyry,  sandstone. 

Wyoming  Limestone,   granite,   trappean   and   volcanic  rocks, 

sandstone. 


226.  THE  MINERALS  OF  BUILDING  STONES.— One 
should  be  generally  familiar  with  the  more  common  mineral  sub- 
stances which  compose  the  more  important  kinds  of  work,  in  order 
to  understand  the  relative  value  of  different  stones  for  building, 
monumental  or  other  purposes. 

Any  rock  is  composed,  as  a  rule,  of  several  different  minerals  in 
a  state  of  aggregation,  and  these  minerals  are  in  turn  made  up  of 
two  or  more  substances  known  as  elements.  There  are  seventy- 
four  known  elements  which  combine  to  form  all  known  matter. 
The  eight  most  important,  in  order  of  abundance,  are  the  follow- 
ing: oxygen,  47.13  per  cent;  silicon,  27.89  per  cent;  aluminum, 
8.13  per  cent;  iron,  4.71  per  cent;  calcium,  3.53  per  cent;  sodium, 
2.68  per  cent ;  magnesium,  2.64  per  cent ;  potassium,  2.35  per  cent. 

The  elements  generally  exist  in  combination  with  one  another,  ♦ 
forming  mineral  substances.  There  are  known,  described  and 
named  about  two  thousand  different  combinations,  but  more  than 
95  per  cent  of  all  the  rocks  generally  considered  in  reports  and 
treatises  on  building  stones  are  composed  of  various  combinations 
of  fourteen  minerals. 


212 


BUILDING  CONSTRUCTION. 


(Ch.V) 


Minerals  are  distinguished  from  one  another  by  (i)  their  chem- 
ical composition,  (2)  their  crystallization  and  (3)  their  physical 
properties. 

The  chemical  composition  is  obtained  by  a  chemical  analysis. 

All  minerals,  which  occur  in  crystals,  crystallize  under  one  of  six 
well-defined  systems. 

The  most  important  physical  properties  are  color,  luster,  cleavage, 
streak  and  hardness. 

Minerals  are  re*ferred  to  a  "scale  of  hardness"  of  ten  units,  com- 
posed of  common  or  well-known  minerals,  as  follows:     (i)  tale, 

(2)  gypsum,  (3)  calcite,  (4)  fluorite,  (5)  apatite,  (6)  orthoclase, 

(7)  quartz,  (8)  topaz,  (9)  sapphire  and  (10)  diamond.  The  hard- 
ness of  any  mineral  is  determined  by  its  ability  to  scratch  the  mem- 
bers of  this  scale,  and  the  degree  of  hardness  is  expressed  by  the 
number  of  the  mineral  in  the  scale,  minerals  of  intermediate  hard- 
ness being  expressed  by  fractions. 

The  important  minerals  and  groups  of  minerals  generally  con- 
sidered in  reference  to  building  stone  are  (i)  quartz,  (2)  feldspar, 

(3)  mica,  (4)  amphibole,  (5)  pyroxene,  (6)  chlorite,  (7)  olivine, 

(8)  talc,  (9)  calcite,  (10)  dolomite,  (11)  magnetite,  (12)  hema- 
tite, (13)  limonite  and  (14)  pyrite. 

These  are  fully  described  in  the  numerous  works  on  mineralogy 
and  it  is  not  possible  or  desirable,  in  the  limits  of  one  chapter  on 
building  stones,  to  enter  into  any  discussion  of  their  properties. 

227.  ROCK  CLASSIFICATION.— All  the  rocks  now  used 
for  constructive  purposes  may  be  classified  under  the  following 
heads  -."^ 

TABLE  XX. 

Classifications  of  Rocks  Used  for  Constructive  Purposes. 
A.    IGNEOUS  ROCKS;  ERUPTIVE. 

(1)  Massive  with  Quartz  and  Orthoclase: 

(a)  Granite  and  Granite  Porphyries. 
{h)  Quartz  Porphyries, 
(c)  Liparites. 

(2)  Massive  without  Quartz: 
ft  (a)  Syenite. 

{b)  Quartz-free  Porphyries, 
(c)  Trachytes  and  Phonolites. 

(3)  Plagioclase  Rocks: 

{a)  Diorites  and  Diorite  Porphyries. 

{b)  Diabases,  Gabbros,  Melaphyrs  and  Basalts. 

*  "Stone  for  Building  and  Decoration."    George  P.  Merrill. 


BUILDING  STONES— GRANITE. 


213 


TABLE  XX  {Continued). 

(4)  Rocks  without  Feldspars : 

{a)  The  Peridotites  (Serpentine  in  part). 
{b)  The  Pyroxenites  (Soapstone  in  part). 

B.  AQUEOUS  ROCKS. 

(1)  Sedimentary: 

(a)  Siliceous:    Sandstones,  Conglomerates,  Breccias,  Clay-slates  and 
Volcanic  Tuffs. 

{b)  Calcareous:  Limestones  and  Dolomites  (including  the  Marbles). 

(2)  Chemical  precipitates :    Onyx  Marbles  and  Travertines ;  Gypsum  and 

Alabaster. 

C.  iEOLIAN  ROCKS. 

^olian  Limestones  (included  under  {b)  above). 

D.    METAMORPHIC  ROCKS. 

(o)  The  Gneisses  and  crystalline  Schists  (included  with  Granite). 
{b)  The  Marbles  (included  here  with  the  Limestones), 
(c)  The  Serpentines  (Verdantique  Marbles  in  part). 

228.  GEOLOGICAL  RECORD. — In  considering  various  build- 
ing stones,  they  are  frequeptly  referred  to  the  various  rock  forma- 
tions in  the  earth's  crust  in  which  they  occur,  and  for  the  con- 
venience of  those  who  are  not  familiar  with  the  order  of  succession 
of  these  formations,  Table  XXI  is  given  on  following  page. 

2.  GRANITE. 

229.  GRANITE. — General  Description. — The  short  descrip- 
tions'^ in  the  following  articles  of  the  principal  building  stones  of 
this  country,  with  the  localities  in  which  they  are  quarried,  will 
enable  the  young  architect  to  get  some  idea  of  their  composition  and 
characteristics  and,  it  is  hoped,  assist  him  in  making  a  judicious 
selection  of  stones  for  special  cases.  The  stones  are  classed  accord- 
ing to  their  structure  and  composition.  The  granites  are  massive 
rocks  occurring  most  frequently  as  the  central  portions  of  mountain 
chains.  They  are  hard,  granular  stones,  composed  principally  of 
quartz,  feldspar  and  mica,  in  varying  proportions.    When  the  stone 

*  For  a  complete  work  on  the  subject  the  reader  is  referred  to  "Stones  for  Building 
and  Decoration,"  by  George  P.  Merrill,  Ph.]).;  John  Wiley  (In;  Sons,  ]nil)lishers.  Aiuch 
valuable  information  relating  to  building  stones  may  also  be  found  in  the  various 
numbers  of  the  monthly  periodical,  Stone. 

The  following  recent  publications  on  building  stones  will  also  be  found  of  great 
interest  and  value: 

"Building  and  Ornamental  Stones  of  Wisconsin,"  by  E.  R.  Buckley,  Bulletin  No.  4 
of  the  Wisconsin  Geological  and  Natural  History  Survey,  1898. 

"The  Quarrying  Industry  of  Missouri,"  by  E.  R.  Buckley  and  H.  A.  Buehler, 
Vol.  II,  2d  Series  of  the  Missouri  Bureau  of  Geology  and  Mines,  1904. 

"The  Granites  and  Gneisses  of  Georgia,"  by  Thomas  L.  W^atson,  Bulletin  No.  9-A, 
of  the  Geological   Survey  of  Georgia,  1902. 

"The  Building  and  Ornamental  Stones  of  North  Carolina,"  by  Thomas  L.  Watson 


214 


BUILDING  CONSTRUCTION. 


(Ch.V) 


TABLE  XXL 

Geological  Record,  or  Order  of  Succession  of  the  Rocks 
Composing  the  Earth's  Surface. 


Quarternary,  or  Post- 
tertiary 

Tertiary,  or  Cenozoic 


Secondary,  or  Meso- 
zoic 


)  )  Recent,  or  Terrace 

\  The  Age  of  Man  >■  Chaniplain 

'  )  Glacial,  or  Drift 

i  Age  of  Mammals  |-  Tertiary  


Cretaceous. 


Age  of  Reptiles    \  Jurassic  


Triassic, 


Carboniferous 
Age 


Devonian,  or  Age 
of  Fishes 


Silurian,  Age  of 
Invertebrates 


Cambrian,  or 
Primordial 


Upper  Silurian 


Lower  Silurian 


J  Upper  ) 
\  Middle  V, 
)  Lower  ) 


Permian 

Carboniferous  

Subcarbonif  erous . 
Catskill 

Chemung  

Hamilton  


Corniferous 

Oriskany 

Lower  Helderberg 

Salina 


Niagara. 


Trenton . . 
Canadian. 


Archae.m,  Pr  -  -am- 
brian 


Pliocene 

Miocene 

Eocene 

Laramie 

Upper 

Middle 

Lower 

Wealden 

Upper  oolite 

Middle  oolite 

Lower  oolite 

LTpper  Lias 

Marlstone 

Lower  Lias 

Keuper 

Muschelkalk 

Bunter  Sandstone 

Permian 

Upper  Coal-measures 

Lower  Coal-measures 

Millstone  Grit 

Upper 

Lower 

Catskill 

Chemung 

Portage 

Genesee 

Hamilton 

Marcellus 

Corniferous 

Schoharie 

Cauda-galli 

Oriskany 

Lower  Helderberg 

Salina 

Niagara 

Clinton 

Medina 

Cincinnati 

Utica 

Trenton 

Chazy 

Quebec 

Calcif  erous 

Potsdam 

Georgian 

St.  John's 

Huronian 

Laurentian 


contains  a  large  proportion  of  quartz  it  is  very  hard  and  difficult  to 
work,  but  when  there  is  a  considerable  proportion  of  feldspar  it 
works  more  easily. 


and  Francis  B.  Lans^y  with  the  collaboration  of  George  P.  Merrill,  Ikilletin  No.  2,  North 
Carolina  Geological  Survey,  1906. 

"The  Fire-Resisting  Qualities  of  Some  New  Jersey  Building  Stones,"  by  W.  E.  Mc- 
Court,  in  Annual  Report  of  the  State  Geologist,  1907. 

"The  Granites  of  Maine,"  by  T.  Nelson  Dale,  with  an  introduction  by  Geo.  O.  Smith, 
Bulletin  No.  313,  United  States  Geological  Survey,  1907. 

"The  Building  and  Decorative  Stones  of  Maryland,"  by  E.  B.  Mathews  and  Geo. 
P.  Merrill.    Vol.  II,  Special  Publications,  Geological  Survey  of  Maryland,  1898. 

"The  Chief  Commercial  Granites  of  Massachusetts,  New  Hampshire  and  Rhode 
Island,"  by  T.  Nelson  Dale,  Bulletin  of  the  United  States  Geological  Survey,  1908. 

"The  Granites  of  Vermont,"  by  T.  Nelson  Dale,  Bulletin  of  the  United  States 
Geological  Survey,  1908. 

"The  Granites  of  Connecticut,"  by  T.  Nelson  Dale.    To  be  published  in  1909. 


BUILDING  STOXES—GRAKITE.  215 

The  color  of  a  granite  is  determined  principally  by  the  color  of 
the  feldspar,  but  the  stone  may  also  be  light  or  dark,  from  the 
light  or  dark  mica  in  it.  The  usual  color  of  granite  is  either 
light  or  dark  gray,  although  all  shades  from  light  pink  to  red  are 
found  in  different  localities. 

The  light  fine-grained  stones  are  the  strongest  and  most  durable, 
although  almost  every  granite  has  sufficient  strength  for  ordinary 
building  construction.  It  generally  breaks  with  regularity  and  may 
be  readily  quarried,  but  it  is  extremely  hard  and  tough  and  works 
with  great  difficulty,  so  that  it  is  a  very  expensive  kind  of  stone  to 
use  for  cut  work.  It  is  impossible  to  do  fine  carving  on  most  of  the 
granites.  They  rank  among  the  best  stones  for  foundations,  base- 
courses,  water-tables,  etc. ;  for  columns  and  all  places  where  great 
strength  is  required ;  and  for  steps,  thresholds  and  flagging,  for 
which  last-mentioned  purpose  they  can  often  be  split. 

Excellent  varieties  of  granite  may  be  obtained  from  any  of  the 
New  England  States,  from  most  of  the  Southern  States,  from  the 
Rocky  Mountain  region,  and  from  California  and  Minnesota. 

As  a  rule  granite  can  be  quarried  in  any  size  required.  Stones 
from  new  quarries  should  be  analyzed  to  see  if  they  contain  iron,  in 
which  case  it  is  dangerous  to  use  them  for  ornamental  pur- 
poses until  their  weathering  qualities  have  been  thoroughly  tested 
by  exposing  them  for  a  long  time  to  the  weather.  If  the  iron  is  a 
sulphurate  it  is  quite  sure  to  stain  them. 

Gneiss  (pronounced  like  ''nice")  has  the  same  composition  as 
granite,  but  the  ingredients  are  arranged  in  layers  which  are  approx- 
imately parallel.  For  this  reason  the  rocks  split  so  as  to  give  parallel 
flat  surfaces,  making  the  stones  valuable  for  foundation  walls,  street 
paving  and  flagging.  Gneiss  is  often  mistaken  for  granite,  and  is 
frequently  called  by  quarrymen  stratified  or  bastard  granite. 

Syenite  also  is  a  rock  resembling  granite,  but  containing  no  quartz. 
It  is  a  hard,  durable  stone,  generally  of  fine  grain  and  light  gray 
color.  The  principal  syenite  quarries  in  this  country  are  near  Little 
Rock  and  Magnet  Cone,  Arkansas.* 

*  In  many  books  and  papers  treating  on  granite,  syenite  is  described  as  a  rock  con- 
sisting of  quartz,  feldspar  and  hornblende,  the  latter  taking  the  place  of  the  mica  in  the 
true  granites.  According  to  the  modern  methods  of  classification  such  rocks  are  called 
"hornblende  granite." 

"The  name  'syenite'  takes  its  origin  from  Syene,  Egypt,  but  the  stone  from  which  it 
was  named  has  been  found  to  contain  more  mica  than  hornblende.  According  to  recent 
lithologists  the  Syene  rock  is  a  hornblende-mica  granite,  while  true  syenite,  as  above 
stated,  is  a  quartzless  rock." — Merrill. 


2l6 


BUILDING  CONSTRUCTION.  (Ch.  V) 


All  three  of  the  above-mentioned  kinds  of  stone  are  badly  affected 
by  fire,  large  pieces  breaking  off  and  the  stone  cracking  badly. 

Fox  Island,  Me.,  Groton,  Conn.,  Woodstock,  Md.,  St.  Cloud,  Minn.,  and 
Nova  Scotia  granites  are  spoiled  at  900°  Fahr.  Hallowell,  Me.,  Red  Beach, 
Me.,  Oak  Hill,  Me.,  and  Quincy,  Mass.,  granites  are  spoiled  at  1,000°  Fahr. 
The  granites  standing  the  highest  fire  tests  are  those  from  Barre,  Vt., 
Concord,  N.  H.,  Ryegate,  Vt.,  Mt.  Desert,  Me. 

230.  DESCRIPTION  OF  SOME  IMPORTANT  GRAN- 
ITES.— 

Maine. 

The  quarries  of  Vinalhaven  and  Hurricane  Islands.  Knox  Co.,  Maine. — 
These  and  the  adjacent  islands  have  been  knov^n  collectively  as  the  Fox 
Islands  and  their  granite  as  Fox  Island  granite. 

These  quarries  are  the  most  extensive  in  the  country;  texture  of  stone 
rather  coarse ;  color,  gray ;  stone  contains  a  small  amount  of  hornblende.  It 
takes  a  good  and  lasting  polish,  and  is  well  adapted  to  all  kinds  of  ornamental 
work  and  to  general  building  purposes.  It  has  been  used  extensively  all  over 
the  country  for  building  and  monumental  purposes. 

The  product  is  used  for  docks,  bridges,  piers,  buildings  and  monuments. 
The  thin  sheets  and  much  of  the  waste  are  made  into  paving  blocks  12  by 
4  by  7  to  8  inches.  The  principal  markets  are  New  York,  Philadelphia  and 
Washington.  Specimen  structures  in  which  Vinalhaven  granite  was  used  are: 
The  new  post-office  building,  Washington,  D.  C. ;  Masonic  Temple,  Philadel- 
phia ;  savings-bank  building,  Wilmington,  Del. ;  new  Board  of  Trade  building, 
Chicago;  new  post-office  and  custom-house,  Brooklyn,  N.  Y. ;  Manhattan 
Bank  building.  New  York.  These  quarries  furnished  also  the  stone  for  the 
new  custom-house  in  New  York,  for  the  Altman  building.  Thirty-fourth 
street  and  Fifth  avenue,  and  for  the  West  street  office-building.  West,  Cedar, 
and  Albany  streets,  New  York,  and  for  some  docks  in  the  same  city. 

These  quarries  supplied  also  8  columns,  51^  to  54  feet  long  by  6  feet 
in  diameter,  for  the  Cathedral  of  St.  John  the  Divine  in  New  York.  It  was 
intended  that  they  should  each  be  of  one  piece,  but  as  both  the  direction  of  the 
rift  at  the  quarry  and  architectural  principles  required  that  they  be  cut  with 
their  long  axes  at  right  angles  to  the  rift,  the  stress  in  the  great  lathe  came 
upon  the  weakest  part  of  the  stone.  However,  as  the  first  stone  put  into  the 
lathe  broke  with  a  long  diagonal  fracture,  it  became  evident  that  the  chief 
difficulty  was  that  the  stone  had  been  subjected  to  too  great  a  torsional  stress 
by  the  application  of  rotary  power  from  one  end  only.  It  therefore  became 
jiecessary  to  make  each  column  in  two  sections,  each  about  26  feet  long. 

Specimen  buildings  in  which  granite  from  the  Hurricane  Islands  quarries 
was  used  are :  The  Suffolk  County  court-house  in  Boston ;  the  St.  Louis 
post-office  and  custom-house ;  two  buildings  for  the  Naval  Academy  at  Annap- 
olis, Md. ;  the  United  States  custom-house.  New  York ;  Pennsylvania  Rail- 
road station  and  base  course  of  Bulletin  building,  Philadelphia. 

Other  Knox  Co.  quarries  are  as  follows:    The  High  Isle  quarry;  granite 


BUILDING  STO.XES— GRANITE. 


slightly  pinkish,  medium  gray,  and  of  medium  to  coarse,  even-grained  texture ; 
used  in  new  Wanamaker  stores,  Philadelphia. 

The  Dix  Island  quarries ;  granite  somewhat  dark  gray  shade,  and  of 
medium  to  coarse,  even-grained  texture;  used  in  United  States  Treasury  De- 
partment extension  at  Washington,  basement  of  Charleston,  S.  C,  custom- 
house, the  New  York  and  Philadelphia  custom-houses. 

The  Sprucehead  quarry;  granite  with  conspicuous  black  and  white  par- 
ticles, and  of  medium  to  coarse  even-grained  texture;  used  in  Carnegie 
Library  building,  Allegheny,  Pa.,  new  post-office  and  custom-house  at  Atlanta, 
Ga.,  the  Mutual  Life  Insurance  Company's  building.  New  York. 

The  Clark  Island  quarry;  granite  bluish  gray,  fine  to  medium  texture; 
used  in  Hartford,  Conn.,  and  Buffalo,  N.  Y.,  post-offices,  and  Standard  Oil 
Company's  building,  New  York. 

The  Long  Cove  quarry;  granite  bluish  gray;  used  in  Albany,  N.  Y.,  post- 
office,  and  Bates  building,  Philadelphia. 

Hallozvell,  Kennebec  Co.,  Maine. — This  stone  is  celebrated  for  its  beauty 
and  fine  working  qualities,  and  is  in  great  demand  for  monuments  and 
statuary.  It  is  a  fine  light  gray  rock,  comparatively  pure,  the  principal  con- 
stituents being  quartz,  feldspar  and  mica.  Has  been  used  extensively  all  over 
the  country. 

About  seven-eighths  of  the  product  go  into  building  and  one-eighth  goes 
into  carved  work.  The  principal  markets  are  Chicago  and  New  York.  Speci- 
men buildings:  Albany,  N.  Y.,  Capitol;  Hall  of  Records  (including  its 
statuary).  New  York;  Brooklyn  Savings  Bank  building.  New  York;  Masonic 
Temple,  Boston  ;  academic  and  library  buildings  at  tfflited  States  Naval  Acad- 
emy, Annapolis,  Md. ;  Illinois  Trust  Company's  building,  Chicago;  North- 
western Insurance  Company's  building,  Milwaukee;  post-office  at  Allegheny, 
Pa.;  American  Surety  Company's  building.  New  York;  Shawmut  Bank  build- 
ing, Boston;  Marshall  Field  building,  Chicago. 

Hallowell  granite  is  of  fine  texture,  and  especially  suited  to  building  work, 
lending  itself  remarkably  well  to  statuary  and  delicate  ornamental  carving. 

The  quarry  consists  of  three  principal  openings,  the  largest  being  800  feet 
long,  400  feet  wide  and  60  feet  deep,  and  is  an  excellent  example  of  the 
gradual  increase  in  thickness  of  sheets  of  granite,  as  they  vary  from  6  inches 
at  the  top  to  14  feet  at  the  bottom,  permitting  the  quarrying  of  stones  of  all 
shapes  and  sizes. 

Among  the  largest  stones  quarried  have  been  the  following: 
I  piece     /3f%  by    4>2    by  50      feet  long,  weighing  100  tons  in  the  rough, 
8  pieces   4>^   "     4K      "  36        "      "  72  " 

16      "       aVz  "     3-S      "  36        "      "  "  60  " 

1  piece  18      "   18        "     2,0     "      "  "  64    "  " 

2  pieces   8      "   18.6      "     3.10   "      "  "  55  " 

1  piece     8,9    "     6.6      "     5,8     "      "  "  34  " 

2  pieces  32.7    "     7.3      "     14     "      "  "  3^ 
I  piece   13.5  "   10. II    "     2.1     "      "          "  30  " 

The  crushing  strength  of  this  granite  is  about  I7*,500  pounds  per  square 
inch. 


2l8 


BUILDING   CONSTRUCTION.  (Ch.V) 


Cumberland  Coiiniy.  Maine,  Quarries. — Brunswick;  medium  gray;  fine, 
even-grained;  used  in  chapel  of  Bowdoin  College,  Brunswick,  Me.,  and  First 
Parish  Church,  Portland,  Me. 

Freeport ;  medium  gray,  slight  bluish  tinge,  fine  even  grain ;  monumental 
work. 

Pownal ;  light  gray,  fine  even  grain,  used  in  chapel  at  corner  of  Seventieth 
street  and  Central  Park,  New  York;  Van  Norden  Trust  Co.'s  building.  Six- 
tieth street  and  Fifth  avenue,  New  York,  and  building  corner  Eighty- first 
street  and  Ninth  avenue.  New  York. 

Franklin  County,  Maine,  Quarries. — The  Maine  and  New  Hampshire 
Granite  Corporation  quarries  are  at  North  Jay.  The  granite  is  of  very  light 
gray  shade,  "white  granite,"  and  of  fine,  even-grained  texture.  Specimen 
structures:  General  Grant's  tomb.  New  York;  Richard  Smith  Soldiers'  and 
Sailors'  Memorial  gateway,  Fairmount  Park,  Philadelphia;  Chicago  and 
Northwestern  Railway  building,  Chicago ;  Western  German  Bank,  Cincinnati ; 
Union  County  Court  House,  Elizabeth,  N.  J. ;  Bowling  Green  building.  New 
York;  etc. 

The  American  Stone  Company's  quarry  also  is  at  North  Jay.  The 
granite  is  identical  with  that  of  the  preceding,  and  was  used  in  all  but  the 
basement  of  Senator  W.  A.  Clark's  residence  on  Seventy-seventh  street  and 
Fifth  avenue.  New  York. 

Hancock  County,  Maine,  Quarries. — Bluehill.  Medium  gray,  coarse,  even- 
grained;  specimen  buildings:  Woman's  Hospital,  New  York;  Mercantile 
Trust  Company's  and  C^edonia  Insurance  Company's  buildings,  St.  Louis; 
part  of  extension  to  House  of  Representatives;  part  of  District  of  Columbia 
n.unicipal  building;  First  Day  and  Night  Bank,  New  York;  Delamar  and 
Brokaw  residences.  New  York;  chemical  laboratory  of  Pratt  Institute,  Brook- 
Ivn,  N.  Y. ;  chemical  laboratory  of  Stevens  Institute  of  Technology,  Hoboken, 
N.J. 

Mount  Desert.  Light  grayish  buff,  coarse  even-grained;  specimen  build- 
ings :  United  States  Mint,  Philadelphia ;  basement  of  the  custom-house,  New 
York ;  new  bridge  over  the  Potomac  River,  Washington.  Light  grayish  pink ; 
the  Crocker  residence.  Darlington,  N.  J. ;  Danforth  Library,  Paterson,  N.  J. ; 
First  National  Bank  building,  Baltimore,  Md.,  Phoenix  National  Bank,  Hart- 
ford, Conn. 

Crotch  Island.  Lavender  medium  gray,  coarse  even-grained;  specimen 
buildings :  Post-office,  Lowell,  Mass. ;  court-house,  Delham,  Mass. ;  cadet 
armory,  Boston,  Mass. ;  Public  Library,  Laconia,  N.  H. ;  Ninth  Regiment 
armory.  New  York;  approaches  to  East  River  bridge.  No.  3,  New  York; 
trimmings  for  University  Heights  bridge,  New  York. 

Moose  Island.  Lavender  medium  gray,  coarse,  even-grained ;  specimen 
buildings :  Gate-house  at  Central  Park,  and  steps  of  Columbia  University, 
New  York;  trimmings  of  Hampton  Dormitory,  Cambridge,  Mass. 

There  are  other  quarries  in  Hancock  County,  in  the  towns  of  Bluehill, 
Brooksville,  Delham,  Franklin,  Long  Island,  Mount  Desert,  Sedgwick,  Ston- 
ington,  Sullivan,  Swans  Island  and  Tremont,  which  have  supplied  granite 
for  important  structures. 


BUILDING  STONES— GRANITE. 


219 


Lincoln  County,  Maine,  Qiiarries.-trThtso.  quarries  are  in  the  towns  of 
Bristol,  Waldoboro  and  Whitefield. 

The  granite  from  the  Waldoboro  quarry  is  of  a  medium  gray  color,  and 
of  fine,  even-grained  texture.  Specimen  buildings :  Buffalo,  N.  Y.,  Savings 
Bank;  armory,  boat-house  and  cadets'  quarters.  United  States  Naval  Acad- 
emy, Annapolis,  Md. ;  Chemical  National  Bank,  New  York. 

Oxford  County,  Maine,  Quarries. — These  quarries  are  in  the  towns  of 
Fryeburg,  Oxford  and  Woodstock.  The  color  of  the  granite  is  medium 
gray  and  medium  cream  gray,  and  specimens  of  the  material  may  be  seen  in 
the  public  library  at  Conway,  N.  H. ;  the  Roman  Catholic  Church,  Berlin, 
Me.;  the  McGillicuddy  block,  Lewiston,  Me.;  all  bridges  and  stations  of  the 
Grand  Trunk  Railway. 

Penobscot  County,  Maine,  Quarries. — These  quarries  are  in  the  town  of 
Hermon,  and  produce  a  black  granite,  described  as  "an  altered  diabase  por- 
phyry of  dark  green  color  and  fine  texture,  with  porphyritic  crystals  of  black 
hornblende  up  to  three-fourths  inch  in  diameter." 

Piscataquis  County  has  a  quarry  in  the  town  of  Guilford,  producing  a 
light  gray  granite. 

Somerset  County  has  quarries  in  the  towns  of  Hartland  and  Norridge- 
wock  producing  granite  of  medium  and  light  gray  color. 

Waldo  County,  Maine,  Quarries. — These  quarries  are  in  the  town  of 
Frankfort,  Lincoln  and  Swanville.  The  color  of  these  granites  is  medium 
and  light  gray,  and  also  black  and  dark  gray,  that  from  Swanville  being  the 
darkest  of  the  fine-textured  granites  of  the  State.  The  grays  have  been  used 
in  the  post-office  at  Lynn,  Mass.,  post-office,  Chicago,  111. ;  post-office,  Mil- 
waukee, Wis. ;  post-office,  Indianapolis,  Ind. ;  United  States  Mint,  Philadel- 
phia, Pa. 

Washington  County,  Maine,  Quarries. — These  quarries  are  located  in  the 
towns  of  Addison,  Baileyville,  Calais,  Jonesboro,  Jonesport,  Marshfield  and 
Millbridge. 

Addison  and  Baileyville  quarries  produce  dark  gray  and  black  shades. 

Calais  quarries  produce  dark  grays,  blacks,  dark  reddish-greenish  grays, 
dark  reddish  shades,  bright  pinkish  shades,  red  shades  and  pink  shades.  The 
Maine  Red  Granite  Company's  granite  works  are  in  Calais,  and  include  the 
most  extensive  plant  for  polishing  granite  in  the  State.  Specimens  of 
polished  work  are  seen  in  the  four  fluted  columns,  22  by  3  feet,  of  Shattuck 
Mountain  red  granite  for  the  court-house  at  Marquette,  Mich.,  and  balusters 
of  gray  granite  for  the  court-house  at  Kansas  City,  Mo.  The  Redbeach 
Granite  Company's  quarry,  in  the  town  of  Calais,  furnished  the  granite,  of  a 
bright  pinkish  color,  for  the  two  corner  wings  of  the  American  Museum  of 
Natural  History,  in  New  York. 

The  Bodwell-Jonesboro  quarries  furnished  a  grayish  pink  colored  granite 
for  the  "Bourse,  Philadelphia;  for  the  West  End  Trust  Co.'s  building,  New 
York;  for  the  custom-house  and  post-office  at  Buffalo,  N.  Y. ;  for  the  Metho- 
dist Book  Concern  building,  and  for  the  Havemeyer  residence.  New  York; 
for  the  custom-house  and  post-office  at  Fall  River,  Mass. ;  for  the  town 


220 


BUILDING  CONSTRUCTION. 


(Ch.Y) 


buildings  at  Peabody,  Mass.,  and  for  the  Western  Savings  Bank  building, 
Philadelphia. 

The  Jonesport  quarries  furnished  a  dark  reddish  gray  granite  for  the 
Colorado  building,  Fourteenth  and  G  streets,  Washington,  D.  C. ;  State 
armory,  Providence,  R.  I. ;  pov^er-house  of  the  Metropolitan  Street  Railway, 
Interurban,  Ninety-fifth  to  Ninety-sixth  streets  and  First  avenue  to  East 
River,  New  York.  These  quarries  also  furnished  the  dark  reddish  gray  gran- 
ite, known  commercially  as  "Moose-a-bec  red,"  for  the  wainscoting  and 
stairway  in  main  entrance  to  Suffolk  County  court-house,  Boston,  Mass. ; 
for  the  American  Baptist  Publication  Society  building,  in' Philadelphia,  Pa., 
and  25  columns  in  the  Roman  Catholic  Cathedral  in  Newark,  N.  J. 

York  Comity,  Maine,  Quarries. — These  quarries  are  in  the  towns  of 
Alfred,  Berwick,  Biddeford,  Hollis,  Kennebunkport  and  Wells,  and  pro- 
duce granites  of  greenish  dark  gray,  very  dark  olive  brownish,  light  gray, 
medium  gray  pinkish  buff,  and  light  gray  shades. 

VERMONT. 

Barre,  Vt. — These  granites  are  light  and  dark  gray,  clean,  fine-grained 
stones,  and  may  be  had  in  almost  any  practicable  size,  free  from  all  blemishes 
and  defects. 

Among  other  granites  of  importance  may  be  mentioned  those  found  in 
Brunswick,  Essex  County ;  Morgan,  Orleans  County ;  Rycgate  and  St.  Johns- 
bury,  Caledonia  County;  Bethel,  Windsor  County,  and  Woodbury,  Washing- 
ton county;  and  those  at  Windsor  and  West  Dummerston. 

Woodbury,  Vt. — The  granite  from  these  quarries  is  a  light  gray,  fine- 
grained stone,  suitable  for  all  kinds  of  buildings  and  constructive  work.  It 
was  used  in  the  following  recently  constructed  buildings : 

Public  buildings :  Pennsylvania  State  Capitol,  Harrisburg,  Pa. ;  Cook 
County  court-house,  Chicago,  111. ;  Kentucky  State  Capitol,  base-course  and 
interior  polished  columns,  Frankfort,  Ky. ;  Iowa  State  Capitol,  steps  and 
platforms,  Allentown  Hospital,  Allentown,  Pa. ;  Syracuse,  N.  Y.,  University 
library;  Syracuse,  N.  Y.,  University  gymnasium;  post-office,  Providence, 
R.  I.;  post-office,  Hamilton,  Ohio;  post-office,  Des  Moines,  Iowa.  Bank  and 
office-buildings :  Commonwealth  Trust  Co.,  Pittsburg,  Pa. ;  Machesney 
building,  Pittsburg,  Pa. ;  Bank  of  Ohio  Valley,  Wheeling,  W.  Va. ;  Schmul- 
bach  building.  Wheeling,  W.  Va. ;  Peoples'  Savings  Bank,  Toledo,  Ohio. 
Hotels :  Hotel  Knickerbocker,  New  York  City ;  National  Hotel,  Rochester, 
N.  Y. ;  Hotel  Pontchartrain,  Detroit,  Mich.  Monumental  work :  Archway 
at  Port  Huron,  Mich. ;  Soldiers'  and  Sailors'  monument,  Scranton,  Pa. ;  Con- 
federate monument.  Springfield,  Mo.  Miscellaneous :  Northern  avenue 
bridge,  Boston,  Mass. ;  Mortuary  Chapel,  Schenectady,  N.  Y. ;  crematory, 
Linden,  N.  J. 

Bethel,  Vt. — The  granite  from  these  quarries  is  a  very  choice  and  beau- 
tiful stone,  ranking  among  the  very  whitest,  and  showing  a  very  fiigh  com- 
pressive strength,  running  up  to  33,150  pounds  per  square  inch.  It  has  been 
used  in  the  following  buildings  : 

Wisconsin  State  Capitol,  Madison,  Wis. ;  Title  Guarantee  and  Trust  Com- 


BUILDING 


STOXES—^ 


GRANITE. 


22L 


pany  building,  176  Broadway,  New  York  City;  Importers'  and  Traders* 
National  Bank,  247  Broadway,  New  York  City;  Essex  County  court-house, 
base  and  approaches,  Newark,  N.  J. ;  American  Bank  Note  Company  build- 
ing, Broad  and  Beaver  streets,  New  York  City ;  Harry  Payne  Whitney  resi- 
dence, Seventy-ninth  street  and  Fifth  avenue,  New  York  City;  Union  Station, 
in  part,  Washington,  D.  C. 

Windsor,  Vt. — At  Windsor  are  operated  quarries  on  Mount  Ascutney, 
from  which  is  produced  a  dark  bronze  green  granite,  used  for  polished 
columns  and  other  work  of  similar  character.  This  granite  was  used  for  the 
sixteen  polished  column  shafts  in  the  interior  of  the  library  building  of  Co- 
lumbia University,  New  York.  They  are  24  feet  inches  long  and  .'!  feet 
and  7  inches  in  diameter.  It  was  used  also  for  thirty-erght  large  columns  for 
the  office  of  the  Bank  of  Montreal,  Montreal,  Canada. 

West  Dummcrston,  Vt. — The  granite  from  these  quarries  come  in  shades^ 
of  white  and  blue.  It  has  been  used  in  the  Royal  Baking  Company's 
office-building,  New  York ;  for  the  interior  columns  in  Cathedral,  Newark,, 
N.  J.;  in  the  Kellogg-Hubbard  Library,  Montpelier,  Vt. ;  the  Patten  resi- 
dence, Evanston,  111. ;  Thames  Loan  and  Trust  Company's  building,  Norwich, 
Conn.;  First  National  Bank  building,  Spring  Grove,  Pa. 

MASSACHUSETTS. 

Quincy,  Mass. — The  Quincy  granite  quarries  are  among  the  oldest  in  the 
country.  The  product  is,  as  a  rule,  dark,  blue-gray  in  color,  coarse-grained 
and  hard.    Composition  :  quartz,  hornblende  and  feldspar. 

It  has  been  used  in  many  buildings,  among  which  may  be  mentioned : 
JThe  United  States  custom-houses  at  Boston,  Providence,  Mobile,  Savannah, 
New  Orleans  and  San  Francisco ;  Masonic  Temple  and  Ridgeway  Library 
buildings,  and  polished  stairways  and  pilasters  of  the  city-hall,  Philadelphia. 

Gloucester,  Cape  Ann;  and  Rockport,  Peahody,  Wyoma,  Lynn  and  Lynn- 
Held,  Mass. — These  quarries  produce  hornblende  granites,  of  a  gray  or  green- 
ish color.  The  material  was  used  in  the  post-office  and  in  several  churches 
and  private  buildings  in  Boston,  Mass.,  and  in  the  Butler  house  on  Capital 
Hill  at  Washington,  D.  C. ;  in  the  towers  and  superstructure  work  for  the 
new  Cambridge  Bridge  between  Boston  and  Cambridge,  Mass. ;  in  Blackwell's 
Island  Bridge,  New  York,  Manhattan  and  Queens  approaches,  and  in  the 
Registry  of  Deeds  and  Probate  court-house  at  Salem,  Mass. 

Mil  ford,  Brockton,  North  Easton,  Mass. — These  quarries  produce  granites 
of  mellow  tints  of  light  creamy  pink,  with  lively  black  spots.  Among  speci- 
men buildings  in  which  they  were  used,  may  be  mentioned  the  following : 
Allegheny  County  court-house  and  jail,  Allegheny,  Pa.;  Chamber  of  Com- 
merce buildings  in  Boston,  Mass.,  and  Cincinnati,  Ohio :  the  polished  columns 
of  the  Madison  Square  Garden  and  of  the  New  York  Herald  building  in 
New  York;  city-hall,  Worcester,  Mass.;  University  Club,  New  York;  Union 
Railroad  station,  Albany,  N.  Y. ;  Pennsylvania  Railroad  terminal  station. 
New  York ;  Public  Library  building,  Boston,  Alass. ;  John  Hancock  Mutual 
Life  Insurance  Co.'s  building,  Boston,  Mass.;  Pennsylvania  building,  Phila- 


222 


BUILDING  CONSTRUCTION. 


(Ch.  V) 


delphia,  Pa. ;  Hanover  National  Bank  building,  New  York ;  Columbia 
University  Library  building,  New  York ;  New  York  Insurance  Company's 
building,  New  York,  and  Continental  National  Bank  building,  Chicago,  111. 
A  polished  sphere,  five  feet  in  diameter,  of  this  granite  surmounts  the  column 
of  Stony  Creek,  Conn.,  reddish  granite,  in  the  battle  monument  at  West 
Point,  N.  Y. 

Framingliam,  Leominster,  Fitehburg,  Clinton,  Fall  River  and  Freetown, 
Mass. — These  quarries  produce  coarse  gray,  strong  and  durable  granites. 

Dedhani,  Mass. — Fine-grained,  light  pink  granites  from  these  quarries 
were  used  in  Trinity  Church  building,  Boston,  Mass. 

Westford,  West  Andover,  Lawrence,  Lozvell,  Ayer,  Becket,  N orthiield, 
Monson  and  towns  in  Worcester  County,  Mass. — These  quarries  produce 
fine-grained  very  light  gray,  sometimes  pinkish  gneiss  of  good  quality. 
Among  specimen  buildings  in  which  the  material  from  the  Monson  quarries 
was  used  may  be  mentioned  the  following:  Hall  of  Records,  Springfield, 
Mass. ;  St.  Francis  Xavicr's  Church,  New  York ;  St.  Leonard's  Church,  Brook- 
lyn, N.  Y.,  and  monastery  at  Hunt's  Point,  N.  Y. 

CONNECTICUT. 

Roxhury  and  Thomaston,  Litchfield  County;  on  Long  Island  Sound, 
Fairfield  County;  Ansonia,  Bradford,  Leetes  Island,  and  Stony  Creek,  New 
Haven  County;  Haddam,  Middlesex  County,  and  Lyme,  Niantic,  Groton  and 
Mason's  Island,  New  London  County,  Conn. — At  all  of  these  places  there 
are  located  extensive  quarries  of  granite  and  gneiss,  which  are  generally  fine- 
grained in  texture  and  light  gray  in  color. 

Stony  Creek,  Conn. — These  granites  are  known  also  as  ''Branford  Gran- 
ites," the  quarries  being  located  in  Stony  Creek,  in  the  township  of  Branford, 
Conn.  These  were. opened  and  developed  by  Norcross  Brothers  in  1887,  and 
contain  practically  inexhaustible  deposits  of  reddish  colored  stone,  well 
adapted  for  constructive,  decorative  or  ornamental  work.  Some  of  the  more 
important  work  in  which  this  granite  has  been  used  is  as  follows :  South 
Terminal  station,  Boston,  Mass. ;  Exchange  building,  Boston,  Mass. ;  in  several 
buildings  at  Columbia  University,  New  York;  Connecticut  River  Bridge, 
Hartford,  Conn. ;  St.  Gaudens'  equestrian  statue  of  General  Sherman  at  en- 
trance to  Central  Park,  New  York ;  the  polished  column  for  the  battle  monu- 
ment at  West  Point,  N.  Y.,  a  monolithic  shaft,  41 feet  long  by  6  feet  in 
diameter;  the  monument  commemorating  the  fiftieth  anniversary  of  the 
opening  of  the  canal  at  Sault  Ste.  Marie,  Mich.,  a  shaft  4  feet  5  inches  square 
at  the  base  and  45  feet  long;  Broad vvay  Chambers,  New  York;  New  York 
Central  post-office  and  office-building,  Lexington  avenue.  New  York;  Belle- 
vue  Hospital,  New  York,  and  the  McKinley  monument,  near  the  city-hall, 
Philadelphia,  Pa. 

Waterford,  Conn. — The  quarries  at  this  place  produce  granites  of  fine 
v/liite  texture  and  of  a  light  color,  well  suited  to  work  of  a  monumental  char- 
acter. Recent  work  in  which  this  stone  is  used  is  represented  by  the  sculp- 
tured monument  to  the  soldiers  and  sailors  in  the  town  of  Northbridge, 


BUILDING  STONES— GRANITE. 


223 


Mass.,  at  Whitinsville ;  and  the  Williamsburg  and  Greenpoint  Savings  Bank, 
New  York. 

NEW  HAMPSHIRE. 

Concord,  N.  H. — A  fine-grained  granite,  light  gray  in  color,  with  a  silver 
lustre;  well-developed  rift  and  grain,  and  remarkable  for  the  ease  with  which 
it  can  be  worked.  Constituents :  opaque  quartz,  soda-feldspar  and  white 
mica.  Well  adapted  for  statuary  and  monumental  purposes,  as  well  as  for 
general  building.  The  stone  is  eminently  durable,  the  New  Hampshire  State 
House,  built  of  this  stone  in  1816-19,  being  still  in  an  excellent  state  of 
preservation. 

From  the  list  of  specimen  buildings  in  which  granite  from  the  Concord 
quarries  was  used  may  be  mentioned  the  following :  Congressional  Library 
and  new  Senate  office  building,  Washington,  D.  C. ;  Union  Trust  building, 
Pittsburg,  Pa. ;  Camden  County  court-house,  Camden,  N.  J. ;  Tradesman 
Trust  Company's  building  and  Alta  Friendly  Society's  building,  Philadelphia, 
Pa. ;  Standard  Oil  Company's  building.  Western  National  Bank  building. 
First  Church  of  Christ  Scientist,  New  York;  and  Blackstone  Library  build- 
ing, Chicago,  111. 

Marlboro  and  FitzwilUam,  N.  H. — These  quarries  produce  light  gray, 
fine,  close-grained  granites,  and  the  following  is  a  list  of  some  of  the  important 
buildings  in  which  they  have  been  used  :  Clark  University  buildings,  and  resi- 
dence of  Jonas  G.  Clark,  Worcester,  Mass. ;  First  Church  of  Christ  Scientist, 
Somerset  hotel,  and  Buckminster  Chambers,  Boston,  Mass. ;  Vanderbilt 
Memorial  Hospital  building,  Newport,  R.  L  ;  city-hall,  Newark,  N.  J. ;  Indus- 
trial Trust  Company's  building,  Pawtucket,.  R.  I.;  Marshall  Field  building-, 
Chicago,  111. ;  and  armory  for  the  Lawrence  Light  Guard,  Medford,  Mass. 

Troy,  N.  H. — These  quarries  produce  a  fine-grained  gray  granite,  of  pro- 
nounced whitish  effect  after  it  is  cut.  Specimen  structures  in  which  it  has^ 
been  used  are :  Cathedral  of  the  Sacred  Heart,  Newark,  N.  J. ;  Pittsburg 
Bank  building,  Pittsburg,  Pa. ;  the  approaches  to  the  Library  of  Congress, 
Washington,  D.  C. ;  and  the  Hanna  mausoleum,  Cleveland,  Ohio. 

Redstone,  N.  H. — The  two  quarries  at  this  place  are  adjacent,  yet  dis- 
tinct. One  produces  granite  of  a  warm  pink  shade,  the  other  a  granite 
of  a  mottled  green  color.  The  following  are  specimen  buildings  in  which 
the  pink  granite  was  used :  Russia  stores,  Boston  and  Maine  union  station, 
Boston,  Mass. ;  Leiter  block,  W.  C.  T.  U.  temple,  Michael  Reese  Hospital, 
Chicago,  111. ;  Brooklyn  Real  Estate  Exchange,  power  station,  59'th  street. 
Franklin  Savings  Bank,  New  York;  Fidelity  Mutual  Life  Association  build- 
ing, Philadelphia,  Pa. ;  Todd  building,  Louisville,  Ky. ;  Cleveland  Chamber  of 
Commerce,  Cleveland,  Ohio ;  First  and  Fourth  National  Bank  buildings,  Cin- 
cinnati, Ohio;  Equitable  Insurance  Company's  building,  Des  Moines,  la.; 
Memphis  Trust  Company's  building,  Memphis,  Tenn. ;  Bank  of  British  North 
America,  Winnipeg,  Canada ;  Richardson  and  Tuck  Halls,  Dartmouth  College, 
Hanover,  N.  H. ;  Erie  Public  Library,  Erie,  Pa.;  State  Library,  Concord, 
N.  H. ;  and  Memorial  Library,  Lowell,  Mass. 


224 


BUILDIXG  COXSTRUCTION. 


(Ch.V) 


Specimen  buildings  in  which  the  green  granite  was  used  are  :  Northwest- 
ern Guaranty  Loan  building,  Minneapolis,  Minn. ;  J.  P.  Maginnis'  residence, 
Chicago,  111.;  Portland  Savings  Bank  building,  Portland,  Me.;  and  building 
at  777  Broadway,  New  York. 

RHODE  ISLAND. 

Westerly,  R.  /.—Granite  of  fine  grain  and  even  texture  and  of  excellent 
quality.  Constituents:  quartz,  feldspar  and  mica,  with  some  hornblende. 
Color,  rich  light  gray  or  pink,  with  a  distinct  tint  of  brown  when  polished. 

Among  the  specimen  buildings  in  which  the  Westerly,  R.  I.,  "red  granites" 
have  been  used  are  the  following:  American  Tract  Society  buildings,  Wash- 
ington Life  Insurance  Company's  building,  American  Exchange  Bank  build- 
ing. New  York;  Travelers'  Insurance  Company's  building,  Hartford,  Conn.; 
Colonial  Trust  Company's  building  and  Arrott  building,  Pittsburg,  Pa. 

NORTH  CAROLINA. 

The  granites  of  North  Carolina  are  distributed  over  about  one-half  the 
total  area  of  the  State,  but  the  productive  part  of  the  area  is  considerably 
less.  Openings  from  which  more  or  less  granite  has  been  quarried  in  the  past 
have  been  made  in  the  majority  of  the  counties  in  which  granites  occur,  but 
in  1906  less  than  a  dozen  quarries  were  being  systematically  worked,  .The 
prevailing  color  is  light  gray,  with  a  pinkish  cast,  and  there  are  also  delicate 
shades.  From  the  quarries  at  Granite  Quarry  in  Rowan  County  come  the 
Belfour  pink  granites,  especially  superior  stones  for  statuary  and  finely 
'carved  work,  for  mausoleums  and  monuments.  Neighboring  quarries  produce 
also  a  gray  granite  which  is  similar  in  all  its  properties  to  the  pink,  except  in 
color.  These  granites  are  of  uniform  color  and  texture  and  take  an  excep- 
tionally high  polish. 

For  very  complete  and  reliable  data  on  the  subject  the  reader  is 
referred  to  "The  Building  and  Ornamental  Stones  of  North  Carolina,"  by 
Thomas  L.  Watson  and  Francis  B.  Laney,  with  the  collaboration  of  George  P. 
Merrill,  Bulletin  No.  2,  of  the  North  Carolina  Geological  Survey.  Raleigh, 
N.  C,  1906. 

GEORGIA. 

The  granites  of  Georgia  are  distributed  over  all  of  the  State  north  of  a 
line  drawn  from  Augusta,  through  Macon  to  Columbus,  with  the  exception 
of  the  extreme  northwestern  portion  of  the  State.  Of  this  section  granites 
and  gneisses  have  been  quarried  only  in  those  counties  comprised  within  the 
limits  of  what  is  known  as  the  "Piedmont  Plateau."  Up  to  1902  less  than  a 
score  of  these  counties  included  the  entire  granite  industry  in  Georgia;  but 
recently  quarry  developments  have  been  rapid.  The  State  has  enormous 
■quantities  of  superior  stone.  The  prevailing  colors  are  light  gray,  dark  gray 
,and  dark  blue-gray. 

In  DeKalb  County  are  situated  the  Stone  Mountain,  Pine  Mountain  and 
Arabia  Mountain  granite  quarries.  The  Stone  Mountain  granite  was  used  in 
the  following  buildings  taken  from  a  larger  list:  LTnited  States  post- 
•office,  Wheeling,  W.  Va. ;  court-house  and  city-hall,  New  Orleans,  La. ; 


BUILDING  STONES— GRANITE. 


225 


terminal  station,  New  Orleans,  La. ;  Fulton  County  court-house  annex  and 
Fulton  County  jail,  North  Avenue  Presbyterian  Church,  First  Methodist 
Church,  First  Baptist  Church,  and  St.  Mark's  Methodist  Church,  United 
States  Federal  prison,  and  the  United  States  post-office  building,  Atlanta,  Ga. 

For  extended  data  the  reader  is  referred  to  "A  Preliminary  Report  on  a 
Part  of  the  Granites  and  Gneisses  of  Georgia,"  by  Thomas  L.  Watson,  Assist- 
ant Geologist,  Bulletin  No.  9 — A,  of  the  Geological  Survey  of  Georgia, 
Altanta,  Ga.,  1907. 

MISSOURI. 

The  major  part  of  the  granite  works  of  Missouri  arc  in  an  area  of  about 
110  to  120  square  miles,  and  confined  to  nine  counties  in  the  southeastern  part 
of  the  State.  In  color  the  granite  varies  from  light  gray  through  different 
shades  of  reddish  pink  to  brownish  red. 

The  stone  has  been  used  in  many  important  buildings  in  St.  Louis,  Kan- 
sas City,  Chicago  and  other  cities. 

For  further  recent  detailed  data  the  reader  is  referred  to  "The  Quarrying 
Industry  of  Missouri,"  by  E.  R.  Buckley  and  H.  A.  Buehler,  Vol.  II,  2d 
Series,  Missouri  Bureau  of  Geology  and  Mines,  Jefferson  City,  Mo.,  1904. 

WISCONSIN. 

The  following  are  the  areas  from  which  granites  have  been  quarried  dur- 
ing the  past  few  years :  Montello,  Berlin,  Waushara,  Utley,  Marquette, 
Granite  City,  Waupaca,  Wausan  and  Amberg,  and  situated  generally  in  the 
north-central  part  of  the  State.  The  quarries  furnish  granites  of  colors  vary- 
ing from  brilliant  red  to  dark  gray. 

From  the  Montello  quarries,  situated  in  the  central  part  of  Marquette 
County,  come  the  dense,  fine-grained,  uniform  bright  red  and  grayish  gran- 
ites. They  rank  among  the  most  durable  granites,  though  necessarily  diffi- 
cult to  cut  and  to  dress.  It  was  from  these  that  the  stone  was  selected  for 
the  sarcophagi  for  General  and  Mrs.  Grant  at  Riverside  Park,  New  York. 
These  granites  were  used  also  in  the  McKinley  monument  at  Canton,  Ohio. 

For  further  detailed  data  the  reader  is  referred  to  "The  Building  and 
Ornamental  Stones  of  Wisconsin,"  by  Ernest  R.  Buckley,  Assistant  Geologist, 
Wisconsin  Geological  and  Natural  History  Survey,  Bulletin  No.  IV,  Madi- 
son, Wis.,  1908. 

OTHER   STATES   AND  SECTIONS. 

Maryland. — Maryland  granites  are  better  adapted  to  general  construc- 
tional work  than  to  monumental  purposes,  and  are  light  to  dark  gray  in  color, 
and  medium  fine-grained  in  texture. 

New  Jersey. — But  few  granite  quarries  have  been  opened,  yielding  mostly 
gneiss,  used  almost  exclusively  for  heavy  construction  work. 

Neiv  York. — Notwithstanding  the  reported  recurrence  of  gneisses  and 
granites,  suitable  for  general  economic  purposes,  over  various  portions  of  the 
eastern  and  northeastern  sections  of  the  State,  the  granite  industry  of  the 
State  of  New  York  is  comparatively  small. 

From  the  quarries  situated  on  the  north  end  of  Picton  Island,  three  miles 
from  Clayton,  N.  Y.,  comes  the  medium-grained  granite  called  "Picton  Island 


226 


BUILDING  CONSTRUCTION. 


(Ch.V) 


Red  Granite."  It  is  a  bright  and  handsome  stone,  well  suited  to  building  pur- 
poses, and  adapted  to  taking  a  high  polish,  j^^mong  the  buildings  in  which,  it 
has  been  used  may  be  mentioned  the  American  Museum  of  Natural  History, 
New  York,  and  25  decorative  polished  columns  in  the  Maryland  Institute 
building  in  Baltimore,  Md. 

Pennsylvania. — This  State  furnishes  nothing  in  the  way  of  granite  rocks 
to  the  markets,  outside  of  its  own  limits.  The  granitic  stone  quarried  is 
gneiss,  with  the  qdarries  grouped  and  in  close  proximity  to  Philadelphia. 

Delaware. — The  production  of  granite  rocks  in  Delaware  is  very  limited, 
the  only  locality  where  quarries  have  been  opened  being  near  Wilmington. 
The  rock  is  a  dark  gray  augite-hornblende  gneiss,  used  for  general  building 
purposes. 

South  Carolina. — A  fine  and  even-textured,  gray  biotite  granite,  of  excel- 
lent quality,  is  quarried  near  Winnsboro,  Fairfield  County,  and  a  granite  of 
slightly  pinkish  hue  occurs  in  the  same  county.  Granite  is  found  in  six  other 
counties  also, 

Tennessee. — Scarcely  anything  in  the  line  of  granite  rock  is  quarried 
*m  this  State. 

Virginia. — The  principal  quarries  are  located  near  Richmond  and  Peters- 
burg, those  near  Richmond  having  produced  a  large  supply  of  stone,  mar- 
keted in  all  States  south  of  New  England.  The  War,  State  and  Navy 
building  in  Washington,  D.  C.,  was  constructed  of  the  Virginia  granite. 
The  Virginia  granites  are  generally  medium  coarse-grained  and  light  gray 
in  color,  and  are  said  to  correspond  very  closely  to  those  of  New  England. 

Minnesota. — The  granites  of  this  State  are  very  similar  to  those  of  Wis- 
consin. They  are  excellent  granites  of  the  gray  and  red,  fine  and  coarse- 
grained varieties,  carrying  hornblende  and  biotite  as  the  chief  accessory  min- 
erals. At  St.  Cloud,  Minn.,  both  gray  and  red  granites  are  quarried,  the 
latter  greatly  resembling  the  Scotch  granite  in  color,  grain  and  polish.  The 
gray  granite  is  about  one-third  quartz  and  two-thirds  feldspar. 

Western  States. — The  granites  of  the  Western  States  have  been  only 
sparingly  quarried.  While  the  rock  abounds  in  both  quantity  and  quality 
throughout  various  portions  of  the  West,  quarrying  is  limited  almost  ex- 
clusively to  California,  Colorado,  South  Dakota,  Montana  and  Oregon ;  and 
it  is  carried  on  sparingly  in  Utah,  Idaho,  Nevada,  Washington  and  Wyo- 
ming. The  granites  of  this  section  of  the  country  range  in  color  from  light 
gray  to  red,  and  in  texture  from  fine  to  coarse  grain. 

In  Colorado  the  principal  quarry  is  at  Gunnison,  which  produces  a  blue- 
gray  granite,  which  may  be  seen  in  the  Colorado  State  House. 

3.  LIMESTONES. 

231.  GENERAL  DESCRIPTION.— This  name  is  commonly 
used  to  include  all  stones  which  contain  lime,  though  differing 
from  each  other  in  color,  texture,  structure  and  origin.  All  lime- 
stones used  for  building  purposes  contain  one  or  more  of  the  fol- 


BUILDING  STONES— LIMESTONES. 


22y 


lowing  substances,  in  addition  to  lime :  Carbonate  of  magnesia, 
iron,  silica,  clay,  bituminous  matter,  mica,  talc  and  hornblende. 

There  are  three  varieties  of  limestone  used  for  building  purposes, 
viz.:    Oolitic  liniestoiie,  niagncsian  limestone  and  dolomite. 

Oolitic  limestones  are  made  up  of  small  rounded  grains  resem- 
bling the  eggs  of  a  fish,  that  have  been  cemented  together  with  lime 
to  form  solid  rocks. 

Magnesian  limestones  include  those  limestones  which  contain  lo 
per  cent  or  more  of  carbonate  of  magnesia. 

Dolomites  are  crystalline  granular  aggregations  of  the  mineral 
dolomite,  and  are  usually  whitish  or  yellowish  in  color.  They  are 
generally  heavier  and  harder  than  limestones. 

Almost  all  varieties  of  limestone  contain  more  or  less  pulverized 
shells,  corals  and  fossils  of  marine  animals.  A  limestone  can  be 
identified  by  its  effervescence  when  treated  with  a  dilute  acid. 

Many  of  the  finest  building  stones  are  limestones,  but  as  they 
are  less  easily  and  accurately  worked  than  sandstones  they  are  not 
so  largely  used  as  the  latter,  except  in  the  localities  where  the  best 
varieties  are  found. 

The  color  of  limestone  is  generally  light  gray,  sometimes  deep 
blue,  and  occasionally  cream  or  buff.  The  light  gray  varieties  often 
resemble  the  light,  fine-grained  granites  in  general  appearance. 

Most  of  the  granular  limestones  take  a  high  polish. 

Good  limestone  should  have  a  fine  grain  and  weigh  about  145 
pounds  per  cubic  foot. 

Many  of  the  limestones  described  below  are  very  durable,  but 
the  light-colored  stones  are  apt  to  become  badly  stained  in  large 
cities,  especially  where  soft  coal  is  used. 

All  kinds  of  limestone  are  destroyed  by  fire,  although  some  varie- 
ties will  stand  a  greater  degree  of  heat  without  injury  than  others. 

232.  DESCRIPTION  OF  SOME  IMPORTANT  LIME- 
STONES.— The  limestones  most  extensively  used  for  building 
purposes  come  from  the  States  of  Illinois,  Indiana,  Ohio,  New 
York  and  Kentucky. 

The  most  celebrated  American  Hmestone  is  that  quarried  at  Bedford, 
Indiana.  It  is  a  light-colored  oolite,  consisting  of  shells  and  fragments  of 
shells  so  minute  as  to  be  scarcely  discernible  to  the  naked  eye  and  cemented 
together  by  carbonate  of  lime. 

This  stone  is  most  remarkably  uniform  in  grain  and  texture,  is  exceed- 
ingly bright  and  handsome  in  color,  and  is  less  liable  to  discolor  than  most 
light  stones. 


2^8  BUILDING   CONSTRUCTION.  (Ch.V) 

It  has  about  the  same  strength  in  vertical,  diagonal  and  horizontal  direc- 
tions, and  when  first  quarried  is  so  soft  that  it  can  be  easily  worked  with  saw 
or  chisel.  It  hardens,  however,  on  exposure,  and  attains  a  compressive 
strength  of  from  10,000  to  12,000  pounds  per  square  inch.  Owing  to  its  fine 
and  even  grain  and  to  the  ease  with  which  it  can  be  cut  in  any  direction,  it  is 
especially  suitable  for  fine  carving  and  is  also  very  durable. 

On  account  of  its  many  excellent  qualities  it  was  selected  by  the  architect 
for  Mr.  George  W.  Vanderbilt's  palatial  residence  at  Biltmore,  N.  C.  It 
was  also  used  in  the  following  buildings :  The  Auditorium  building,  Chi- 
cago;  the  Manhattan  Life  Co.'s  building,  New  York;  the  mansion  of  Mr. 
C.  J.  Vanderbilt  on  Fifth  avenue.  New  York;  the  State  Capitols  at 
Indianapolis,  Ind.,  Jackson,  Miss.,  Frankfort,  Ky.,  and  Atlanta,  Ga. ;  Walters 
art  gallery,  Baltimore,  Md. ;  Public  Library  and  Museum  building,  Milwau- 
kee, Wis. ;  State  Historical  building,  Madison,  Wis. ;  court-house,  Hunting- 
ton, Ind. ;  Catholic  Cathedral,  Pittsburg,  Pa. ;  Trinity  building  and  Boreel 
annex,  New  York  City,  N.  Y. ;  Federal  building,  Indianapolis,  Ind. ;  St. 
Paul's  Cathedral,  Pittsburg,  Pa. ;  all  the  buildings  for  the  University  of 
Chicago,  Chicago,  111. ;  main  art  palace.  World's  Fair,  St.  Louis,  Mo. ;  First 
National  Bank,  San  Francisco,  Cal. ;  all  buildings  for  the  University  of  Iowa, 
both  at  Iowa  City  and  Ames,  Iowa ;  Union  Club,  New  York  City,  N.  Y. ; 
Yacht  Club,  New  York  City,  N.  Y. ;  the  Handley  Library  at  Winchester,  Va. 
In  the  residence  of  E.  G.  Fabri,  New  York  City,  Bedford  stone  was  used  for 
both  exterior  and  interior  work. 

Bedford  stone  is  of  the  same  geological  age  as  the  famous  Portland  stone 
of  England,  out  of  which  St.  Paul's  Cathedral  of  London  is  constructed. 
Below  is  given  a  comparative  analysis : 

Portland  Stone.    Bedford  Stone. 
Carbonate  of  Lime   95- 16  97.26 


Silica                                                                    1.20  1.69 

Oxide  of  Iron  50  .49 

Magnesia                                                               1.20  .37 

Water  and  loss                                                     1.94  .19 


100.00  100.00 

Regarding  the  crushing  strength,  a  test  made  by  the  United  States  Gov- 
ernment gives  the  crushing  strength  of  Bedford  stone  at  about  135,000 
pounds  per  square  foot.  That  this  enables  it  to  sustain  an  enormous  weight 
ic  shown  by  the  following  table  of  maximum  weights  borne  by  the  piers  and 
masonry  of  some  well-known  structures : 

Pounds  per  sq.  foot. 


Piers  of  St.  Peter's  Rome   33,ooo 

Piers  of  St.  Paul's,  London   39,ooo 

Piers  of  Brooklyn  Bridge   S7,ooo 

Granite  Masonry  of  Washington  Monument  45,000 

Reliable  sustaining  weight  of  Bedford  stone  135,000 


BUILDIXG  STOXES—LIMIISTOXES. 


229 


Indiana  limestone,  or  Bedford  stone,  is  not  as  porous  as  Portland  stone, 
the  English  product.  It  is  more  easily  worked,  responding  readily  to  mailer 
and  tool  in  the  hands  of  workmen,  and  it  can  also  be  planed  or  turned  by- 
machinery,  which  advantage  adds  to  its  desirability,  as  ft  minimizes  the  cost 
of  preparing  it. 

The  oolitic  belt  of  Indiana  extends  over  a  portion  of  the  counties  of 
Lawrence  and  Monroe,  and  is  about  thirty  miles  in  length  and  about  six  miles 
in  width.  It  is  a  homogeneous  limestone,  the  upper  ledges  of  which  are  light 
buff  in  color.  At  a  depth  of  about  30  feet  the  stone  in  most  places  changes 
abruptly  to  a  decided  blue  shade.  The  texture  and  other  chemical  properties 
remain  the  same  from  the  point  wliere  the  color  changes  to  a  depth  of  about 
30  feet  more,  at  which  point  the  stone  becomes  very  coarse,  and  seems  to  be 
of  a  shelly  formation. 

Alabama  has  a  dark  compact  limestone,  some  of  it  closely  resembling  • 
the  Bedford,  Indiana,  stone. 

Arkansas  produces  a  durable,  oolitic  limestone  suitable  for  building,  and 
also  a  cream-colored  magnesium  limestone  of  good  quality. 

Colorado   furnishes  a  coarse,   reddish  limestone,  and  also  a  compact, 
finely  crystalline  black  stone. 

In  Florida  there  is  a  loose  and  porous  oolitic  limestone  at  Key  West, 
and  the  coarse,  porous  shell  limestone  called  "Coquina"  quarried  at  Anastasia 
Island. 

In  Illinois  almost  the  entire  building  stone  product  is  limestone  or 
dolomite,  with  a  few  sandstone  quarries.  The  most  notable  of  the  limestones 
is  the  fine-grained,  very  light  colored  Niagara  stone  from  near  Lemont  and 
Joliet.  There  are  many  other  localities  in  the  State  which  furnish  excellent 
varieties  of  building  stone. 

There  are  large  quarries  of  limestone  also  at  Grafton  and  Chester,  and 
from  the  quarries  at  East  Fort  Madison,  Hancock  County,  111.,  come  the 
"Appanoose  Dolomite  Stone,"  a  strong  and  durable  stone. 

lozL'a  abounds  in  limestones  and  dolomites,  which,  however,  so  far  enjoy 
only  a  local  reputation.  There  are  numerous  small  quarries,  producing,  how- 
ever, many  good  building  stones. 

Kansas  has  limestones  and  dolomites  of  generally  light  color,  and  of  soft 
and  porous  texture,  although  there  are  some  exceptions,  several  varieties 
having  a  firm  and  compact  texture  and  acquiring  a  good  surface  and  finish. 

There  are  large  quarries  of  limestone  in  the  vicinity  of  Topeka.  This 
stone  can  be  worked  almost  as  easily  as  wood,  and  yet  becomes  hard  and 
durable  when  placed  in  a  building.  There  are  also  several  small  quarries 
which  supply  the  local  demand  in  various  parts  of  the  State. 

Kentucky  has  limestones  of  the  finest  quality  and  in  inexhaustible  quan- 
tities, the  oolitic  limestones  being  without  superiors,  if  indeed  they  have 
equals.  But  these  building  stones  are  almost  unknown  in  the  principal  mar- 
kets, and  such  as  are  quarried  have  only  a  local  reputation. 

The  best  known  of  the  Kentucky  limestones  is  probably  the  Bowling 
Green  oolitic  stone  quarried  at  Memphis  Junction.  This  stone  is  almost 
identical  in  composition  with  the  celebrated  "Portland"  stone  of  Great  Brit- 


230 


BUILDING  CONSTRUCTION, 


(Ch.  V) 


ain.  Its  color  is  light  gray.  It  is  as  readily  worked  as  the  Bedford  stone,  is 
very  durable,  and  is  pre-eminent  in  its  resistance  to  the  discoloring  influences 
of  mortar,  cement  and  soil. 

The  "Green  River  Stone"  comes  from  the  quarries  at  Hadley,  Warren 
County,  Ky.,  which  produce  a  stone  dark  in  color  -when  first  quarried,  but 
bleaching  out  white  upon  exposure  to  the  weather.  The  stone  is  similar  to 
the  Bedford  stone,  being  a  close-grained  oolitic  limestone.  It  was  used  in  the 
Pennsylvania  State  Library  building,  Harrisburg,  Pa.,  the  residence  of  S.  B. 
Elkins,  Philadelphia,  Pa.,  and  the  Daviess  Company  Bank  building,  Owens- 
boro,  Ky. 

Maine  has  little  if  any  limestone  that  is  well  adapted  for  building  stone, 
as  it  is  generally  blue  or  blue-black,  veined  with  white,  a  combination  thought 
to  be  not  desirable, 

Michigan  has  limestones  and  dolomites  suitable  for  building  stones,  but 
they  have  been  but  comparatively  little  quarried. 

Minnesota  furnishes  limestones  and  dolomites  generally  of  a  light  buff, 
drab  or  blue  color,  fine-grained  and  compact. 

Missouri's  limestones  and  sandstones  from  all  formations  have  been 
used  to  some  extent  in  buildings.  A  majority  of  the  quarries  in  the  sedi- 
mentary formations  are  engaged  exclusively  in  producing  stone  to  supply  the 
local  market. 

At  Carthage,  Jasper  County,  Missouri,  there  are  extensive  quarries  of 
limestone,  which  produce  large  quantities  of  both  quicklime  and  building 
stone.  The  stone  is  coarse-grained  and  crystalline,  takes  a  good  polish,  and 
is  well  adapted  to  exterior  finishing. 

Excellent  quarries  of  limestone  exist  also  at  Phoenix,  Missouri,  the  stone 
being  shipped  to  St.  Louis,  Kansas  City  and  Omaha. 

Nebraska  has  carboniferous  limestones  in  several  counties  of  such  quality 
as  to  render  them  suitable  for  building  purposes;  but  few  if  any  of  them  are 
in  demand  outside  the  limits  of  the  State. 

New  York  has  several  limestones  belonging  to  seven  or  eight  different 
geological  formations.  A  gray  limestone  is  quarried  at  Lockport  and  Roches- 
ter, N.  Y.,  which  is  extensively  used  for  trimmings  in  that  State  and  in  some 
parts  of  New  England.  The  limits  of  this  chapter  will  not  permit  any  con- 
sideration of  these  several  building  stones,  and  the  reader  is  referred  to  the 
various  publications  bearing  upon  the  stones  of  New  York  State. 

North  Carolina. — On  account  of  the  lack  of  a  large  enough  market  and 
of  transportation  facilities,  the  limestones  and  dolomites,  although  of  very 
good  quality  for  building  purposes,  are  not  extensively  quarried. 

Ohio. — The  limestones  and  dolomites  of  Ohio,  while  in  many  instances 
used  locally  for  building  purposes,  are  employed  chiefly  for  rough  founda- 
tion work,  street  paving  and  flagging  and  for  making  quicklime.  This  is 
because  they  are  generally  of  a  dull  and  uninteresting  color,  and  not  well 
suited  for  any  kind  of  fine  building  or  ornamental  work,  although  often 
strong  and  durable.  There  are  large  quarries  of  limestone  at  Dayton  and 
Sandusky. 


BUILDING  STOXES— MARBLES. 


231 


Pennsylvania. — Formations  in  Montgomery,  Lancaster  and  Chester  Coun- 
ties furnish  gray  or  bluish  gray  limestone,  used  for  general  building.  Other 
localities  furnish  calcareous  dolomites,  limestone,  breccias,  etc.,  none  of  which 
possesses  such  characteristics  as  would  make  it  of  more  than  local  value.  From 
the  Avondale,  Chester  County,  Pa.,  quarries  comes  the  "Avondale  Limestone," 
varying  in  color  from  white  to  light  brownish  gray.  It  has  been  used  in 
many  churches  and  other  buildings  in  Philadelphia,  Pa.,  and  in  buildings  in 
neighboring  cities  and  towns. 

Tennessee. — None  of  the  limestones  are  quarried  for  anything  more  than 
local  use. 

Texas. — Near  Austin,  and  also  in  Burnett  County,  are  respectively  found 
light-colored,  fine-grained  limestones,  and  dark  mottled  limestones ;  and  near 
San  Saba,  compact,  fine-grained  cretaceous  limestones  of  poor  quality. 

Iflseonsin. — A  large  part  of  the  State  is  immediately  underlain  by  lime- 
stone, the  suitability  of  which  for  building,  purposes  is  widely  different,  in 
different  localities.  The  colors  range  from  buff  or  straw  yellow  to  dark 
bluish  gray.  In  some  parts  of  the  State  the  limestone  is  closely  compacted 
and  crystalline,  often  resembling  marble.  In  other  places  it  has  a  loose, 
open  texture.  Bridgeport,  Trempealeau  and  Maiden  Rock  furnish  mag- 
nesian  limestone  suitable  for  all  ordinary  purposes.  The  Trenton  forma- 
tion, on  which  many  of  the  important  cities  of  the  State  are  located, 
furnishes  a  blue  limestone  extensively  used  locally  for  buildings.  It  has 
proven  satisfactory  where  there  is  no  danger  from  freezing.  At  Watwatosa, 
Lannan,  Genesee,  Marblehead,  Sturgeon  Bay  and  Knowles  there  is  a  good 
limestone  generally  siiited  to  building  purposes, 

4.  MARBLES. 

233.  GENERAL  DESCRIPTION.— Marble  is  simply  a  crys- 
tallized limestone,  capable  of  taking  a  good  polish. 

The  scarcity  and  constant  expense  of  good  marbles  have  in  the 
past  prevented  them  from  being  used  in  constructional  work,  except 
occasionally  for  columns.  Most  of  the  marbles  obtained  from  the 
older  quarries  also  stain  so  easily  that  they  are  considered  unde- 
sirable for  exterior  work. 

Since  the  rapid  development  of  the  Georgia  and  Tennessee  quar- 
ries, however,  the  marbles  taken  from  them  have  been  much  used 
for  exterior  finish,  and  even  for  the  entire  facing  of  the  walls.  They 
will  probably  be  more  extensively  used  for  exterior  work  in  the 
future,  as  they  are  exceedingly  strong  and  durable  and  do  not 
readily  stain. 

Nearly  all  varieties  of  marble  are  wprked  with  comparative  ease, 
and  the  fine-grained  varieties  are  especially  adapted  to  fine  carving. 
They  generally  resist  frost  and  moisture  well,  they  are  admirably 


232 


BUILDING  CONSTRUCTION. 


(Ch.  V) 


suited  for  interior  decoration,  sanitary  purposes,  etc.,  and  in  clear, 
dry  climates  make  splendid  material  for  exterior  construction. 

The  compressive  strength  of  marble  varies  from  5,000  to  20,000 
pounds  per  square  inch,  but  it  is  only  when  used  for  columns  that 
this  strength  need  be  considered. 

For  the  composition  and  strength  of  various  marbles  see  the 
tables  in  the  Appendix. 

234.  PRODUCTION  OF  MARBLE  IN  THE  UNITED 
STATES. — The  marble  output  in  the  United  States  in  1906  was 
valued  at  $7,582,938. 

Vermont  produces  the  greater  part  of  the  marble  of  the  United 
States,  the  output  of  this  State  representing  60.36  per  cent  of  the 
total  output  of  the  country  in  1906,  and  amounting  to  about 
1,400,000  cubic  feet. 

In  that  year  Georgia  ranked  second  in  the  marble-producing 
States,  its  value  of  output  representing  12.12  per  cent  of  the  total 
of  the  United  States,  and  amounting  to  875,000  cubic  feet. 


TABLE  XXII. 

Distribution  and  Value  of  Output  of  Marble^   1902- 1906, 

FOR  Various  Uses. 


Use 

1902 

1903 

1904 

1905 

1906 

Sold  by  producers  in  rouj^h  state 

Ornamental  purposes  

Dressed  for  monumental  work . 
Interior  decoration  in  buildings 

Total  

$2,275,429 
1,038,802 
7,300 
956,870 
679,913 
86,368 

$2,454,263 
1,111,072 
51,359 
1,062,339 
663.558 
20,100 

$2,599,052 
988.671 
21,554 
1,211,389 
1,257,96:3 
219,206 

$2,987,542 
1,168,450 
13,643 
1,170,279 
1,682,651 
106.506 

$1,795,169 
1,559,925 
44,523 
2,214,872 
1,722.445 
246,(X)4 

$5,044,182 

$5,362,686 

$6,297,835 

$7,129,071 

$7,582,938 

In  1906  the  next  States  and  territories  in  order  of  output  were 
Tennessee,  New  York,  Massachusetts,  Maryland,  Pennsylvania, 
California,  Alabama,  Washington,  Arkansas,  Nevada,  Utah, 
Wyoming,  New  Mexico,  Missouri  and  Alaska. 

In  Pennsylvania's  output  is  generally  included  a  production  of 
serpentine  from  Northampton  county,  and  small  quantities  of  ser- 
pentine are  also  generally  included  in  the  Georgia  outputs. 

The  outputs  of  California,  New  Mexico,  Utah  and  Wyoming 
often  include  small  quantities  of  onyx. 

The  greater  part  of  the  marble  output  is  for  building  and  monu- 
mental work,  the  values  for  the  two  being  nearly  equal  in  1906. 


BUILDING  STOXES— MARBLES. 


233 


Table  XXII  shows  the  various  uses  to  which  the  marble  quarried 
in  1902,  1903,  1904,  1905  and  1906  was  put. 

From  this  table  it  appears  that  while  the  rough  .marble  sold  to 
manufacturers,  dealers  and  contractors  decreased  in  value,  the 
dressed  stone  of  all  kinds  sold  by  the  quarrymen  increased. 

235.  DESCRIPTION  OF  SOME  IMPORTANT  AMERI- 
CAN  MARBLES. — Great  quantities  of  white  and  black  marble 
are  quarried  in  this  country,  but  nearly  all  of  the  beautiful  streaked 
and  colored  marbles  are  imported. 

Vermont  Marble. — This  State  is  the  greatest  producer  of  marble  of  any 
State  in  the  Union,  the  total  product  in  1906  amounting  to  $4,576,913,  more 
than  the  combined  value  of  all  other  marbles  quarried  in  the  country. 

The  largest  quarries  are  at  West  Rutland  and  Proctor. 

Among  other  towns  in  which  the  marble  quarrying  industry  has  been  par- 
ticularly active  may  be  mentioned  Dorset,  East  Dorset,  Wallingford,  Pitts- 
ford,  Brandon  and  Middlebury, 

In  texture  Vermont  marble  is,  as  a  rule,  fine-grained,  although  some 
of  it  is  coarse-grained  and  friable.  In  color  it  varies  from  pure  snowy 
white  through  all  gradations  of  bluish,  and  sometimes  greenish  shades,  often 
beautifully  mottled  and  veined,  to  deep  blue-black,  the  bluish  and  dark  vari- 
eties being,  as  a  rule,  the  finest  and  most  durable. 

These  marbles  are  used  principally  for  monumental  and  statuary  work, 
and  for  decorative  work,  sanitary  fittings,  tiling,  etc.,  in  buildings. 

At  Proctor  the  stone  is  very  massive,  and  large  blocks  are  taken  out 
for  general  building  purposes. 

Vermont  marble  has  been  used  for  the  exterior  and  interior  of  innu- 
merable buildings.  Merel}^  as  illustrations  the  following  specimen  buildings  in 
which  it  has  been  used  may  be  mentioned :  Church  of  our  Lady  of  Good 
Council,  East  9th  street,  and  Church  of  the  Ascension,  107th  street.  New 
York;  United  States  post-office  and  court-house,  Worcester,  Mass.;  water 
tower,  Fort  Ethan  Allen,  Essex,  Vt. ;  Hart  Memorial  Library,  Troy,  N.  Y. ; 
Clio  Hall,  Princeton  College,  Princeton,  N.  J. ;  Metropolitan  Club,  Ne\\^ 
York;  Second  National  Bank  building,  Paterson,  N.  J.;  Knickerbocker  Trust 
Company's  buildings  and  Engineers'  Club,  New  York;  United  States  post- 
office  building,  Waterloo,  Iowa;  court  of  new  Federal  building,  Cleveland, 
Ohio ;  public  library,  Atlantic  City,  N.  J. ;  Tufts  College  Library  building. 

Georgia. — This  State  contains  extensive  beds  of  marble,  which  of  late 
years  have  come  into  very  general  use.  The  quarries,  which  are  situated  in 
the  northern  part  of  the  State,  produce  :  1st.  A  clear  white  marble,  bright  and 
sparkling  with  crystals.  2d.  A  marble  with  a  dark  mottled  white  ground, 
with  dark  blue  mottlings ;  and  also  one  with  a  light  blue  and  gray  ground, 
with  dark  mottlings.  3d.  A  white  marble,  with  dark  blue  spots  and  clouds, 
and  a  bluish-gray  marble,  with  dark  spots  and  clouds.  4th.  Pink,  rose- 
tinted  and  green  marbles  in  several  shades.  The  appearance  of  the  Georgia 
marbles  is  quite  different  from  that  of  the  marbles  from  the  other  States. 


234 


BUILDING  CONSTRUCTION. 


(Ch.  V) 


The  stone  is  an  almost  pure  carbonate  of  lime,  free  from  foreign  or 
hurtful  ingredients.  It  is  remarkably  non-absorbent,  and  absolutely  impervious 
to  liquids,  including  even  ink;  and  it  is  not  subject  to  discoloration,  atmos- 
pheric changes  or  decay.  If  soiled  by  dust  or  smoke  it  can  be  easily  cleaned 
by  washing  with  clean  water  alone,  so  as  to  look  as  bright  as  when  first 
finished. 

Georgia  marble  has  been  extensively  used  for  monuments  and  for  the 
interior  finish  of  buildings,  notably  in  the  Congressional  Library  building  at 
Washington,  D.  C.  It  is  also  used  more  and  more  every  year  for  exterior 
construction,  either  for  trimmings  or  for  the  entire  walls.  It  may  be  seen  on 
the  exterior  of  the  following  buildings,  given  as  illustrations :  St.  Luke's 
Hospital  building,  New  York ;  post-office,  Tampa,  Fla. ;  Century  building, 
St.  Louis,  Mo.;  Bank  of  Montreal,  Winnipeg,  Canada;  Equitable  building, 
Atlanta,  Ga. 

It  may  be  seen  on  the  exterior  and  interior  of  the  following:  Girard 
Trust  and  Banking  Company,  Philadelphia,  Pa. ;  Royal  Bank  of  Canada, 
Montreal,  Canada;  Century  building.  Atlanta,  Ga. 

It  may  be  seen  in  the  interior  of  the  following:  Terminal  station, 
Atlanta,  Ga. ;  Kentucky  State  Capitol  building,  Frankfort,  Ky. ;  Wilson  build- 
ing, Dallas,  Texas ;  House  of  Representatives  office-building,  Washington, 
D.  C. ;  court-house,  Mendon,  Neb. ;  Marion  hotel,  Little  Rock,  Ark. ;  Patten 
hotel,  Chattanooga,  Tenn. 

'Tennessee. — Marble  has  been  quarried  in  this  State  since  1838,  the  prin- 
cipal quarries  being  in  the  vicinity  of  Knoxville,  in  East  Tennessee.  The 
varieties  of  marble  produced  from  these  quarries  include  grays,  light  pinks, 
dark  pinks,  buffs,  chocolate  and  drabs.  Only  the  pinks  and  the  grays,  how- 
ever, are  suitable  for  general  building  purposes,  the  darker  colors  being  con- 
fined principally  to  furniture  and  interior  work.  The  stone  is  98  per  cent 
carbonate  of  lime.  The  pink  and  gray  varieties  are  well  adapted  to  building 
purposes,  their  density  and  resistance  to  crushing  being  equal  to  that  of  any 
other  marbles  in  the  world. 

They  also  offer  great  resistance  to  moisture,  and  are  practically  imper- 
vious to  the  staining  or  discoloring  agencies  of  the  atmosphere,  except,  per- 
haps, those  which  are  found  in  large  manufacturing  centers.  Under  favorable 
conditions  there  appears  to  be  no  reason  why  they  should  not  last  for  ages  on 
the  exterior  of  buildings.  The  highly  colored  varieties  are  among  the  hand- 
somest produced  in  this  country. 

Neiv  York. — There  are  several  quarries  of  gray,  blue  and  white  marble 
just  north  of  New  York  City  which  furnish  good  building  marble,  but 
not  quite  good  enough  for  decorative  work.  Much  of  it  has  been  used  for 
building  purposes  in  New  York  City,  and  the  best  yet  obtained  from  this 
series  of  deposits  are  those  of  Tuckahoe  and  Pleasantville  in  Westchester 
County. 

At  Gouverneur,  in  St.  Lawrence  County,  there  is  a  very  coarsely  crystal- 
line light  gray  magnesian  limestone,  which,  while  too  coarse  for  carved 
work,  answers  well  for  massive  structures,  and  acquires  a  good  surface  and 
polish. 


BUILDING  STONES— MARBLES.  235 

In  Clinton  County  are  found  excellent  fine-grained  colored  marbles  of 
gray  and  gray-and-pink  shades,  known  as  "Lepanto"  and  "French  Gray,"  and 
very  extensively  used  for  general  interior  work. 

The  best  quality  of  black  marble  is  quarried  at  Glens  Falls,  on  the  Hudson 
River. 

Massachusetts. — In  Berkshire  County  arc  medium  fine-grained  white  or 
gray  marbles  used  for  general  building.  At  Egremont  are  coarsely  crystal- 
line white  and  gray  limestones  from  which  were  obtained  the  large  Corin- 
thian columns  of  Girard  College,  Philadelphia.  From  the  Lee  quarries  came 
the  marble  used  in  the  Capitol  extension  in  Washington,  D.  C,  and  in  the 
city  buildings  in  Philadelphia. 

Pennsylvania. — In  this  State  are  several  quarries  of  a  granular  white  and 
mottled  marble,  which  have  furnished  a  great  deal  of  this  stone  for  Phila- 
delphia buildings. 

Maryland. — Baltimore  County  is  the  important  marble-producing  center  of 
the  State,  and  contains  the  white  stone  of  the  Beaver  Dam  quarries,  from 
which  the  26-foot  monoliths  used  in  1859-61  in  the  National  Capitol  were 
obtained.  Nearby  are  the  coarsely  crystalline  white  limestones  from  which 
the  material  was  obtained  for  the  lower  150  feet  of  the  Washington  monu- 
ment, in  Washington,  D.  C. 

Colorado. — This  State  contains  beautiful  varieties  of  marble,  which  it  is 
thought  in  time  may  take  the  place  of  much  of  the  foreign  marble  now 
imported.  At  present  only  a  few  quarries  are  worked.  In  Gunnison  County, 
on  the  Yule  Creek  and  Crystal  River,  there  is  a  belt  of  white  marble  appar- 
ently superior  in  quality  to  anything  found  elsewhere  in  the  United  States. 
This  marble  belt  is  about  100  feet  in  thickness  and  not  less  than  six  miles 
in  length.  The  prevailing  colors  are  pure  white,  creamy  white,  and  white 
slightly  clouded  with  gray. 

Other  States  and  Territories. — The  other  States  and  territories  men- 
tioned in  Article  234  have  valuable  marbles  which  are  quarried  in  smaller  and 
various  quantities,  and  used  for  rough  and  dressed  work,  for  general  building 
purposes,  for  monumental  and  ornamental  work  and  for  interior  decoration. 

236.  ONYX  MARBLE. — The  composition  of  these  stones  is  the 
same  as  that  of  the  common  marbles,  but  they  vv^ere  formed  by 
chemical  deposits  instead  of  in  sedimentary  beds  crystallized  by  the 
action  of  heat.  ''They  owe  their  banded  structure  and  variegated 
colors  to  the  intermittent  character  of  the  deposition  and  the  pres- 
ence or  absence  of  various  impurities,  mainly  metallic  oxides.  The 
term  onyx  as  commonly  applied  is  a  misnomer,  and  has  been  given 
merely  because  in  their  banded  appearance  they  somewhat  resemble 
the  true  onyx,  which  is  a  variety  of  agate." 

Owing  to  their  translucency,  delicacy  and  variety  of  colors,  and 
to  the  readiness  with  which  they  can  be  worked  and  polished,  the 
onyx  marbles  are  considered  the  handsomest  of  all  building  stones, 
and  they  bring  the  highest  price  also;  the  cost  per  square  foot  for 


236  BUILDING   CONSTRUCTION.  (Ch.V) 

slabs  I  inch  thick  varying  from  $2.50  to  $6.  Their  use  is  confined 
to  interior  decoration,  such  as  wainscoting,  mantels,  lavatories,  and 
to  small  columns,  table  tops,  etc.  Most  of  the  onyx  marble  used  in 
the  United  States  is  imported  from  Mexico,  although  considerable 
onyx  is  quarried  at  San  Luis  Obispo,  California ;  and  quarries  of 
very  beautiful  stone  have  recently  been  opened  near  Prescott,  Ari- 
zona. The  Mexican  onyx  presents  a  great  variety  of  colors,  such 
as  creamy  white,  amber-yellow  and  light  green,  each  generally 
more  or  less  streaked  or  blotched  with  green  or  red.  Some  of  the 
light  stones  have  beautiful  translucent  clouded  effects.  When  cut 
across  the  grain  the  stone  often  presents  a  beautifully  banded  struc- 
ture like  the  grain  of  wood.  Cutting  the  stone  across  the  grain, 
however,  reduces  its  strength  greatly,  so  that  it  is  necessary  to  back 
it  with  slabs  of  some  stronger  marble. 

The  San  Luis  Obispo  stone  is  nearly  white,  finely  banded  and- 
translucent,  and  it  takes  a  beautiful  surface  and  polish. 

The  Arizona  stone  presents  a  greater  variety  of  coloring,  ranging 
from  milky  white  to  red,  green,  old  gold  and  brown,  the  colors  inter- 
mingled in  every  possible  way.  Up  to  the  present  time  a  compara- 
tively small  amount  of  this  stone  is  on  the  market,  but  farther 
developments  will  probably  result  in  the  production  of  large  quan- 
tities of  it. 

5.  SANDSTONES. 

237.  GENERAL  DESCRIPTION.— ^'Sandstones  are  composed 
of  rounded  and  angular  grains  of  sand  so  cemented  and  compacted 
together  as  to  form  a  solid  rock.  The  Cementing  material  may  be 
silica,  carbonate  of  lime,  an  iron  oxide  or  clayey  matter." 

They  include  some  of  the  most  beautiful  and  durable  stones  for 
exterior  construction ;  and  on  account  of  the  ease  with  which  they 
can  be  worked,  and  because  of  their  wide  distribution  throughout 
the  country,  they  are  used  more  extensively  than  any  other  stones 
for  exteriors. 

The  grains  of  sand  themselves  are  nearly  the  same  in  all  sand- 
stones, being  generally  pure  quartz ;  the  character  of  the  stone 
depends  principally  upon  the  cementing  material.  If  the  latter  is 
composed  entirely  of  silica,  the  rock  is  light-colored  and  generally 
very  hard  and  difficult  to  work.  When  the  grains  have  been 
cemented  together  by  fusion  or  by  the  deposition  of  silica  between 
the  granules,  and  the  whole  hardened  under  pressure,  the  rock  is 


BUILDING  STONES—SANDSrONES. 


257 


almost  the  same  as  pure  quartz  and  is  called  quartaite,  one  of  the 
strongest  and  most  durable  of  rocks.  *'If  the  cementing  material  is 
composed  largely  of  iron  oxides  the  stone  is  red  or  brownish  in  color 
and  usually  not  too  hard  to  work  readily.  When  the  cementing 
material  is  carbonate  of  lime  the  stone  is  light-colored  or  gray,  soft 
and  easy  to  work."  Such  stones  do  not  as  a  rule  weather  well,  as 
the  cementing  material  becomes  dissolved  by  the  rain,  thereby  caus- 
ing a  loosening  of  the  grains  and  allowing  the  stones  to  dis- 
integrate. Clay  is  still  more  objectionable  than  lime  as  a  cementing" 
material,  as  it  readily  absorbs  water  and  renders  the  stones  liable 
to  injury  by  frost. 

In  several  sandstones  some  of  the  grains  consist  of  feldspar  and 
mica,  which  have  a  tendeifty  to  decrease  the  strength. 

Sandstones  have  a  great  variety  of  colors;  brown,  red,  pink,  gray^ 
buff,  drab  or  blue,  in  varying  shades,  being  common  varieties.  The 
color  is  due  largely  to  the  iron  in  the  composition.  The  oxides  of 
iron  do  no  harm,  but  no  light-colored  sandstone  should  be  used  for 
exterior  work  which  contains  iron  pyrites,  or  sulphate  of  iron,  as  it 
is  almost  sure  to  cause  stain  or  rust. 

Sandstones  vary  in  texture  from  almost  impalpable  fine-grained 
Stones  to  those  in  which  the  grains  are  like  coarse  sand.  All  other 
conditions  being  the  same,  the  fine-grained  stones  are  the  strongest 
and  most  durable  and  take  the  sharpest  edge.  Sandstones  being  of 
a  sedimentary  formation,  are  often  laminated,  or  formed  in  layers; 
and  if  they  set  "on  edge,"  or  with  the  natural  bed  or  surface  par- 
allel to  the  face  of  a  wall,  their  outside  face  is  quite  sure  to  dis- 
integrate or  peel  off  in  time.  All  laminated  stones  should  always  be 
laid  on  their  natural  bed.  When  freshly  quarried,  sandstones  gener- 
ally contain  a  considerable  quantity  of  water,  which  makes  them 
soft  and  easy  to  work,  but  at  the  same  time  very  liable  to  injury  by 
freezing  if  quarried  in  winter  weather.  Many  Northern  quarries 
cannot  be  worked  in  winter  on  this  account.  Almost  all,  if  not  all, 
sandstones  harden  as  the  quarry-water  evaporates,  so  that  many  of 
them  which  are  very  soft  when  first  quarried  become  hard  and  dur- 
able when  placed  in  a  building.  Such  stones,  however,  should  not 
be  subjected  to  much  weight  until  they  are  dried  out. 

There  is  a  great  abundance  of  fine  sandstone  of  all  colors  dis- 
tributed throughout  the  United  States,  so  that  it  is  not  difficult  to 
get  first-class  stone  for  any  building  of  importance.  Most  of  the 
sandstones  in  the  Eastern  part  of  the  country  are  either  red  or 


23B 


BUILDING  CONSTRUCTION. 


(Ch.V) 


brown  in  color,  there  being  no  merchantable  light  sandstones  east 
oi  Ohio. 

238.  PRODUCTION  OF  SANDSTONE.— In  1906  Pennsyl- 
vania, New  York,  Ohio  and  California,  with  values  of  $1,346,140, 
$724,164,  $659,611,  $400,083  respectively,  were  the  ranking  States 
in  the  building-sandstone  output. 

239.  DESCRIPTION  OF  SOME  IMPORTANT  SAND- 
STONES.— The  following  are  some  of  the  best-known  sandstones 
in  this  country,  any  of  which  are  good  building  stones : 

Connecticut  brozvnstonc  includes  all  the  dark  brown  sandstones  quarried 
in  the  neighborhood  of  Portland,  Conn.  It  is  a  handsome  dark  brown  stone, 
tinted  slightly  reddish,  has  a  fine  even  rift,  is  easy  to  work,  and  gives  a 
bea-jtiful  surface  when  rubbed.  This  stone  "ts  decidedly  laminated,  and  the 
surface  will  soon  peel  if  the  stone  is  set  on  edge.  When  laid  on  its  natural 
bed,  however,  it  is  very  durable.  This  was  the  first  sandstone  quarried  in  the 
country,  and  great  quantities  of  it  have  been  used  in  New  York  City. 

The  following  is  a  brief  resume  of  the  properties  of  Connecticut  brown- 
stone  and  a  list  of  some  of  the  recent  buildings  in  which  it  was  used : 

Color. — Brown,  evenly  laminated,  uniform  and  permanent.  No  discolor- 
ation appears  after  many  years'  exposure  to  the  weather. 

Texture. — Sandstone,  triassic,  fine  and  even-grained.  Easy  "to  work. 
Free  from  clay,  marl  or  gravel. 

Uses. — Used  for  exterior  and  interior  of  churches,  college  buildings, 
public  buildings,  private  houses,  apartment-houses  and  all  kinds  of  buildings ; 
also  for  bridge  masonry,  retaining-walls,  foundations,  rubble  masonry,  pier, 
dyke  and  dock  construction. 

Strength. — Crushing  strength  from  13,330  to  15,020  pounds  per  square  inch. 

Chemical  Properties. — Chemical  analysis  shows  them  to  be  as  follows : 


The  following  is  a  short  list  of  some  recent  buildings  erected  of  this  stone: 
Wesleyan  University,  Middletown,  Conn.,  North  College  dormitory ;  Wesleyan 
University,  Middletown,  Conn.,  Fisk  Hall;  U.  S.  Government  post-office, 
New  Bedford,  Mass. ;  U.  S.  Government  post-office,  Hoboken,  N.  J. ;  U.  S. 
Government  post-office,  Bridgeport,  Conn.;  lining  of  chancel,  St.  Mark's 
Episcopal  Church,  Evanston,  111.;  Episcopal  Church,  Troy,  N.  Y. ;  Univer- 
salist  Church,  Meriden,  Conn.;  Caldwell  H.  Colt  Memorial  building,  Hart- 


Silica  

Alumina   

Iron  Oxide  

Manganese   

Lime   

Magnesia   

Soda,  Potash,  etc 


70.11 

1349 
-  4-85 
•35 
2.39 
1.44 

7-37 


100.00 


BUILDING  STONES—SANDSTONES. 


fcrd,  Conn.;  High  Schoo'  building,  Hartford,  Conn.;  John  H.  Hall  Memorial 
building,  Portland,  Conn.;  Packer  Institute,  .Brooklyn,  N.  Y. ;  residence  of 
Governor  Murphy,  Newark,  N,  J.;  Canadian  Bank  of  Commerce,  Toronto, 
Canada. 

Longmcadow  Stone. — This  is  a  reddish  brown  sandstone  quarried  prin- 
cipally at  East  Longmeadow,  Mass.  It  is  an  excellent  building  stone,  without 
any  apparent  bed,  and  may  be  cut  in  any  way.  It  varies  from  quite  soft  to 
very  hard  and  strong  stone  and  should  be  selected  for  good  work.  It  has 
been  largely  used  throughout  the  New  England  States  for  the  past,  twenty- 
five  years. 

The  following  are  some  of  the  specimen  buildings  in  which  the  Long- 
meadow  stone  was  used :  Sever  Hall,  Harvard  College,  Cambridge,  Mass. ;. 
Osborn  Memorial  Hall,  Yale  College,  New  Haven,  Conn. ;  Marshall  Field 
building,  Chicago,  111. ;  Trinity  Church,  Youth's  Companion  building,. 
Mechanics'  Arts  high-school,  Boston,  Mass. ;  Waldorf-Astoria  hotel. 
Teachers'  College,  New  York ;  Commencement  Hall  and  Library  building, 
Princeton  College,  Princeton,  N.  J. ;  South  Unitarian  Church,  Worcester,  Mass. 

Potsdam  Red  Sandstone,  from  Potsdam,  N.  Y.,  is  a  quartzite  and  one  of 
the  best  building  stones  in  the  country,  being  extremely  durable  and  equal  tO' 
granite  in  strength.  It  was  used  in  All  Saints'  Cathedral,  Albany,  N.  Y.,  and 
m  the  Dominion  Houses  of  Parliament,  in  Ottawa,  Canada.  There  are  three 
shades,  chocolate,  brick-red  and  reddish  cream. 

Hummelstozvn  Browiistone,  from  Hummelstown,  Pa.,  is  a  medium  fine- 
grained stone,  bluish  brown  or  slightly  purple  in  color,  the  upper  layers  being 
more  of  a  reddish  brown  and  much  resembling  the  Connecticut  stone.  The 
stone  compares  very  favorably  with  the  other  brownstones  mentioned,  and  is 
in  very  general  use  in  the  principal  Eastern  cities. 

The  following  is  a  short  list  of  recent  buildings  constructed  of  this  stone: 
North  American  building.  Broad  and  Sansom  streets,  Philadelphia,  Pa. ; 
Emory  M.  E.  Church,  Pittsburg,  Pa. ;  Corpus  Christi  R.  C.  Church,  Buffalo, 
N.  Y. ;  Market  and  Fulton  National  Bank,  New  York  City ;  Wyatt  building, 
14th  and  F  streets,  Washington,  D.  C. ;  Arcade  building,  Cleveland,  Ohio; 
court-house,  Orlando,  Fla. ;  First  Universalist  Church,  Watertown,  N.  Y. ; 
.National  Exchange  Bank,  Hopkins  place,  Baltimore,  Md. ;  M.  J.  Heyer 
office-building,  Wilmington,  N.  C. 

North  Carolina,  West  Virginia  and  Indiana  contain  quarries  of  brown- 
stone  which  supply  the  local  demaiid  and  the  stones  from  which  are  worthy 
of  a  wider  distribution,  particularly  those  of  North  Carolina. 

Fond  dii  Lac,  Minnesota,  furnishes  a  reddish  brown  sandstone  which 
closely  resembles  the  Connecticut  brownstone,  but  which  is  much  harder  and 
firmer.  "The  stone  consists  almost  wholly  of  quartz  cemented  with  silica 
and  iron  oxides." 

Kettle  River  Sandstone. — At  Banning,  Minnesota,  are  quarries  from 
which  this  stone  is  taken.  It  is  a  siliceous  sandstone,  and  of  a  uniform  light 
salmon  color.  It  was  used  in  the  Main  Library  building.  University  of 
Illinois,  Urbana,  111. ;  in  the  interior  of  the  United  Presbyterian  Church,  at 
Worcester,  Mass. ;  Spokane  Club  building,  Spokane,  Wash. ;  Public  Library, 


240 


BUILDING  CONSTRUCTION.  (Ch.  V) 


building,  Des  Moines,  Iowa ;  court-houses  at  Elk  Point,  S.  D. ;  Crookston, 
Grand  Rapids  and  Benson,  Minn. 

Lake  Superior  Sandstones. — These  are  brown  and  red  sandstones  of  the 
Potsdam  formations.  There  are  quarries  at  Portage  Entry  and  Marquette, 
Mich.,  producing  the  red  and  brown  shades,  respectively,  and  at  Port  Wing, 
Wis.,  producing  the  brown  shades.  The  Portage  red  sandstone  was  used  in 
the  Waldorf-Astoria  hotel,  Manhattan  Savings  Institution,  Altman's  new 
stores.  New  York ;  Board  of  Trade  building,  Toronto,  Canada ;  Carnegie 
office-building,  Pittsburg,  Pa. ;  city-hall,  Omaha,  Neb.  The  Port  Wing 
brown  sandstone  was  used  in  the  new  armory  building,  St.  Paul,  Minn,; 
Carnegie  Public  Library  building,  Duluth,  Minn. 

Ohio  Stone. — The  finest  quality  of  light  sandstone  in  the  United  States  is 
quarried  in  the  towns  of  Amherst,  Berea,  East  Cleveland,  Elyria  and  Inde- 
pendence, Ohio,  and  is  commonly  known  as  "Ohio  stone"  or  "Berea  stone.'* 
It  is  a  fine-grained,  homogenous  sandstone,  of  a  very  light  buff,  gray  or  blue- 
gray  color,  and  is  very  evenly  bedded.  The  stone  is  about  95  per  cent  silica, 
the  balance  being  made  up  of  small  amounts  of  lime,  magnesia,  iron  oxides, 
alumina  and  alkalies.  There  is  but  little  cementing  material,  the  various 
particles  being  held  together  mainly  by  cohesion  induced  by  the  pressure  to 
which  they  were  subjected  at  the  time  of  their  consolidation.  They  are  very 
soft,  work  readily  in  every  direction,  and  are  especially  fitted  for  carving. 

"Unfortunately  the  Berea  stone  nearly  always  contains  more  or  less  iron 
pyrites  and  needs  to  be  selected  with  care.  Most  of  the  quarries,  however, 
have  been  traversed  by  atmospheric  waters  to  such  a  degree  that  all  processes 
of  oxidation  which  are  possible  have  been  very  nearly  completed."* 

The  stone  can  be  furnished  in  blocks  of  any  desired  size  and  uniform 
color.  It  is  shipped  to  all  parts  of  the'  country,  and  is  in  great  demand  for 
fine  buildings.  Mr.  H.  H.  Richardson,  the  celebrated  architect,  often  used  it 
in  contrast  with  the  Longmeadow  sandstone  for  trimmings  and  decorative 
effects.  It  contains  from  about  6  to  8  per  cent  of  water  when  first  taken 
from  the  quarry,  and  about  4  per  cent  when  dry.  It  cannot  be  quarried  in 
winter  on  account  of  the  splitting  of  the  stone  caused  by  the  freezing  of  the 
water  contained  in  it.  There  are  some  fourteen  or  fifteen  different  companies 
that  quarry  this  stone  for  the  market. 

The  following  are  some  representative  buildings  in  which  this  Ohio  sand- 
stone has  been  used  :  Calvary  M.  E.  Church,  Allegheny,  Pa.,  gray  "Canyon" 
stone;  Sixth  United  Presbyterian  Church,  Pittsburg,  Pa.,  buff  Amherst  stone; 
Jewish  Synagogue,  Washington,  D.  C  ,  Berea  stone ;  Masonic  Temple,  Minne- 
apolis, Minn.,  Berea  stone ;  Planters'  hotel,  St.  Louis,  Mo.,  Berea  stone ;  the 
Canadian  Bank  of  Commerce,  Winnipeg.  Canada,  gray  "Canyon"  stone ; 
State  Historical  Library,  Minneapolis,  Minn.,  buff  Amherst  stone;  O.  N.  G. 
armory,  Cleveland,  Ohio,  Berea  stone ;  city-hall,  Milwaukee,  Wis.,  Berea 
stone ;  city-hall,  St.  Louis,  Mo.,  buff  Amherst  stone ;  city-hall,  Davenport, 
Iowa,  Berea  stone;  Taber  opera-house,  Denver,  Col.,  buff. 

"The  Waverly  sandstone  comes  from  Southern  Ohio.  This  is  a  fine- 
grained homogenous  stone  of  a  light  drab  or  dove  color,  which  works  with 

*  "Stones  for  Building  and  Decoration."    George  P.  Merrill. 


BUILDIXG  STONES—SLATES. 


241 


facility,  and  is  very  handsome  and  durable.  It  forms  the  material  of  which 
many  of  the  finest  buildings  in  Cincinnati  are  constructed,  and  is,  justly,  highly 
esteemed  there  and  elsewhere."* 

Ohio  is  the  largest  producer  of  sandstone  of  any  State  in  the  Union. 

At  Warrcnsburg,  Mo.,  there  is  quarried  a  gray  sandstone  which  has  been 
used  in  many  important  buildings  in  Kansas  City. 

The  Rocky  Mountain  region  also  furnishes  great  quantities  of  fine  sand- 
s<'l)nes.  In  Aricona  there  is  quarried  a  very  fine-grained  chocolate  sandstone, 
which  t^kes  a  fine  edge  and  is  excellently  adapted  for  rubbed  and  moulded 
work.  A  considerable  quantity  of  it  is  used  in  Denver,  Col.,  on  account  of 
its  pleasing  color,  and  it  is  also  shipped  east  of  the  Missouri  River. 

At  Manitou,  Col.,  there  are  inexhaustible  quarries  of  a  fine  red  stone, 
much  resembling  the  Longmeadow  stone  of  Massachusetts,  but  of  a  lighter 
red  color.  It  has  no  apparent  bed  and  weathers  well.  It  has  sufficient 
strength  for  ordinary  purposes.  At  Fort  Collins,  Col.,  there  is  quarried  a 
much  harder  and  slightly  darker  stone,  which  is  excellent  for  almost  any 
purpose.  It  has  sufficient  strength  for  piers  and  columns,  and  is  hard  enough 
for  steps  and  thresholds.  It  is  much  harder  to  cut  than  the  Manitou  stone, 
and  hence  is  more  expensive;  but  it  is  at  the  same  time  more  durable.  This 
stone  has  been  shipped  as  far  East  as  New  York  City.  Colorado  also  contains 
an  inexhaustible  supply  of  sandstone  flagging,  admirably  adapted  for  founda- 
tions and  sidewalks ;  it  is  as  strong  as  granite,  and  may  be  quarried  in  slabs 
of  almost  any  size  or  thickness. 

A  red  and  buff  sandstone  is  quarried  at  Glcnrock,  Wyoming,  which  has 
been  used  in  Omaha,  Nebraska. 

The  Rawlins,  Wyoming,  gray  sandstone  has  been  used  in  the  following- 
buildings  :  The  Wyoming  State  Capitol  and  the  United  States  post-office 
at  Cheyenne,  Wyo. ;  the  State  University  at  Laramie,  Wyo. ;  court-house, 
school-house  and  State  Penitentiary  at  Rawlins,  Wyo. ;  residence  cf  John  F. 
Campion,  Denver,  Col. ;  court-house  at  Beatrice.  Neb. ;  opera-house,  Kearney, 
Neb. ;  public  park  building  and  several  store  buildings  at  San  Francisco,  Cal. 

California  has  many  quarries  of  sandstone,  the  larger  number  of  which 
are  in  Santa  Clara  County.  Stanford  University  is  built  of  a  light-colored 
sandstone  quarried  at  San  Jose,  Cal. 

Owing  to  the  sparsely  settled  condition  of  the  country  and  the  lack  of 
railroad  facilities,  the  building  stones  of  the  Western  portion  of  the  United 
States  have  been  but  little  developed,  but  with  the  building  up  of  that  part 
of  the  country  the  quarrying  industry  will  undoubtedly  become  one  of  great 
importance. 

6.  SLATES. 

240.  GENERAL  DESCRIPTION.— Although  slate  is  not 
strictly  a  building  stone,  it  is  largely  used  for  covering  the  roofs 
of  buildings,  for  blackboards,  sanitary  purposes,  etc.,  and  the  archi- 
tect should  be  familiar  with  its  qualities  and  characteristics. 


Ira        Raker,  "Masonry  Construction." 


242 


BUILDING  CONSTRUCTION. 


(Ch.V) 


The  ordinary  slate  used  for  roofing  and  other  purposes  is  a  com- 
pact and  more  or  less  metamorphosed  siHceous  clay.  Slate  stones 
originated  as  deposits  of  fine  silt  on  ancient  sea  bottoms,  which  in 
the  course  of  time  became  covered  with  thousands  of  feet  of  other 
materials  and  finally  turned  into  stone. 

''The  valuable  constituents  in  slate  are  the  silicates  of  iron  and 
alumina,  while  the  injurious  constituents  are  sulphur  and  the  can^ 
bonates  of  lime  and  magnesia." 

One  of  the  most  valuable  characteristics  of  slate  is  its  decided 
tendency  to  split  into  thin  sheets,  whose  surfaces  are  so  smooth  that 
they  lie  close  together,  thus  forming  a  light  and  impervious  roof 
covering.  These  plans  of  cleavage  are  caused  by  intense  lateral 
pressure,  and  are  generally  at  very  considerable  though  varying 
angles  with  the  ancient  bedding. 

The  most  valuable  qualities  of  slate  are  its  strength,  its  tough- 
ness and  its  non-absorptive  character. 

241.  USES  OF  SLATE. — Slate  is  used  principally  for  roofing 
purposes,  but  it  is  used  also  for  billiard  table  tops,  mantels,  floor 
tiles,  steps,  flagging,  fittings  for  toilet-rooms,  school  blackboards, 
school  slates  and  pencils,  electrical  supplies  and  for  numerous  other 
purposes. 

242.  PHYSICAL  FROFERTIES.— Strength  and  Hardness.— 
From  various  tests  that  have  been  made  on  the  quality  of  slate,  it 
appears  that,  in  general,  the  strongest  specimens  are  the  heaviest 
and  softest,  as  they  are  also  the  least  porous  and  corrodible.  "The 
tests  for  strength  and  corrodibility  are  probably  those  of  greatest 
importance  in  forming  an  opinion  regarding  the  value  of  the  slate 
under  actual  conditions  of  service."  * 

Mr.  Mansfield  Merriman  suggests  that  specifications  should 
require  roofing  slates  to  have  a  modulus  of  rupture  for  transverse 
strength  greater  than  7,000  pounds  per  square  inch. 

If  the  slate  is  too  soft  the  nail  holes  will  become  enlarged  and 
the  slate  will  get  loose.  If  it  is  too  brittle  the  slate  will  fly  to 
pieces  in  the  process  of  squaring  and  holing,  and  will  be  easily 
broken  on  the  roof.  "A  good  slate  should  give  out  a  sharp  metallic 
ring  when  struck  with  the  knuckles ;  should  not  splinter  under  the 
slater's  axe ;  should  be  easily  'holed'  without  danger  of  fracture, 
and  should  not  be  tender  or  friable  at  the  edges." 


*  Mansfield  Merriman  in  Stone,  April,  1895. 


B  UILDING    STONES—SLA  TES. 


The  surface  when  freshly  spHt  should  have  a  bright  metallic  luster 
and  be  free  from  all  loose  flakes  or  dull  surfaces. 

Color. — The  color  of  slate  varies  from  dark  -blue,  bluish  black 
and  purple  to  gray  and  green.  There  are  also  a  few  quarries  of 
red  slates.  The  color  of  slate  does  not  appear  to  indicate  its  quality. 
The  red  and  dark  colors  are  generally  considered  the  most  effective 
in  appearance,  while  the  greens  are  used  principally  on  factories, 
storehouses  and  buildings  where  the  appearance  is  not  of  so  much 
importance. 

Some  slates  are  marked  with  bands  or  patches  of  a  different  color, 
and  the  dark  purple  slates  often  have  large  spots  of  light  green 
upon  them.  These  spots  do  not  as  a  rule  affect  the  durability  of 
the  slates,  but  detract  greatly  from  their  appearance. 

As  a  rule  the  dark  color  of  slates,  particularly  that  of  the  slates 
of  Maine  and  Pennsylvania,  appears  to  be  due  to  particles  of  car- 
bonaceous matter  contained  in  them. 

"The  red  slates  of  New  York  are  made  up  of  a  ground  mass  of 
impalpable  red  dust  in  which  are  imbedded  innumerable  quartz  and 
feldspar  particles." 

Absorption. — A  good  slate  should  not  absorb  water  to  any  per- 
ceptible extent,  and  if  a  slate  is  immersed  in  water  half  its  height 
the  water  should  not  rise  in  the  upper  half ;  if  it  does,  it  shows 
that  the  slate  is  not  of  good  quality. 

*Tf,  upon  breathing  upon  a  slate,  a  clayey  odor  be  strongly 
emitted,  it  may  be  inferred  that  the  slate  will  not  weather." 

Grain. — Good  slates  have  a  very  fine  grain.  They  should  be  cut 
lengthwise  of  the  grain,  so  that  if  they  break  on  the  roof  they  will 
not  become  detached,  but  will  divide  each  into  two  slates,  each  held 
by  a  nail. 

Market  Qualities. — The  market  qualities  of  slate  are  classed 
according  to  their  straightness,  smoothness  of  surface,  fair,  even 
thickness,  and  also  according  to  the  presence  or  absence  of  dis- 
coloration. 

243.  PRODUCTION  OF  SLATE.— There  were  9  States  re- 
porting a  commercial  output  of  slate  in  the  United  States  in  1906 
— Pennsylvania,  Vermont,  Maine,  Virginia,  Maryland,  California, 
New  York,  Arkansas  and  Georgia,  named  in  the  order  of  value 
of  output.    Besides  these  States  Arizona,  New  Jersey,  Tennessee 


244 


BUILDING  CONSTRUCTION. 


(Ch.V) 


and  Utah  have  deposits  more  or  less  developed.  The  production 
for  1906  was  reported  as  valued  at  $5,668,346. 

There  has  been  a  gradual  decrease  in  the  number  of  squares  of 
slate  made  in  this  country,  due  to  a  decrease  of  export  trade,  the 
English  market,  where  American  slates  found  considerable  sale  for 
several  years,  being  now  supplied  either  from  the  Welsh  quarries, 
in  consequence  of  the  settlement  of  strikes  in  these  quarries,  or  by 
small-sized,  cheaper  French  roofing  slates.  The  decrease  is  also  due 
to  labor  troubles  in  the  building  trades  for  the  last  four  or  five 
years,  to  strikes  in  the  slate  quarries,  and  to  the  fact  that  the 
present  building  conditions  in  large  cities  do  not  call  for  slate  roofs, 
the  roofs  being  more  nearly  fiat,  and  the  large  number  of  patent- 
roofing  processes  and  tiles  being  cheaper  and  more  convenient  than 
the  slate.  This  condition  is,  however,  ofifset  outside  of  cities,  espe- 
cially in  the  vicinity  of  quarries,  by  the  high  price  of  wooden 
shingles  and  the  great  durability  of  slate  roofing.,  The  scarcity  and 
high  price  of  labor  has  also  been  a  factor  in  the  decreased  output. 
During  the  last  five  years  smaller  sizes  of  slate  have  been  sold, 
making  the  average  value  lower.  The  roofing  slate  in  1906  was 
reported  as  1,214,742  squares,  valued  at  $4,448,786.  Average  value 
per  square,  $3.66  in  1906. 

•  This  table  gives  the  number  of  "squares"  of  slate  and  the  values 
of  same,  by  States,  for  1906 : 


Squares.  Value. 

California    10,000  $80,000  * 

Georgia    1,000  5,000 

Maine   18,498  100,916 

Maryland    25,288  129,965 

New  York   10,788  60,000 

Pennsylvania    755,966  2,710,249 

Vermont    354-134  1,189,799 

Virginia   39»o68  172,857 


Total  1,21 4,742  $4,'448,786 


A  ^'square"  of  slate  is  the  number  of  slates  required  to  lay  100 
square  feet  of  roof,  allowing  a  3-inch  lap.  The  estimated  weight 
of  roofing  slate  of  ordinary  thickness  is  650  pounds  to  the  square, 
and  the  slate  is  generally  shipped  in  carload  lots  of  from  50  to  90 
squares  per  carload. 

The  following  shows  the  average  price  of  roofing  slate  per  square 


BUILDING  STONES- 


—SLATES. 


245 


from  1901  to  1906  for  the  entire  country:  1901,  $3.15;  1902,  $3.45; 
1903,  $3.88;  1904,  $3.78;  1905,  $3,69;  1906,  $3.66. 

There  is  practically  no  slate  imported  into  the  United  States.  In 
1906  the  importations  were  valued  at  $9,471,  of  which  only  $228 
was  for  roofing  slate. 

The  value  of  roofing  slate  exported  from  the  United  States  in 
1906  was  $255,785,  the  chief  slate  export  trade  being  to  the  United 
Kingdom,  Canada  and  British  Australasia.''' 

244.  TRADE  CLASSIFICATION  OF  SLATE.— Slates  are 
classified  in  the  trade  by  the  name  of  the  region  in  which  they  are 
quarried,  some  regions  extending  into  two  or  more  States.  Several 
regions  are  contained  in  the  State  of  Pennsylvania.  The  product 
from  each  region  is  more  or  less-  distinctive  from  that  of  other 
regions.  .The  more  important  producing  regions  are: 

Vermont  and  New  York  region  ;  Bangor  region.  Pa. ;  Lehigh  region,  Pa. ; 
Pen  Argyl  region.  Pa.;  Maine  region;  Northampton  hard-vein  region,  Pa.; 
Peach  Bottom  region,  Md.  and  Pa. ;  Virginia  region. 

The  slates  of  the  Bangor,  Pen  Argyl  and  Lehigh  regions  and  the 
Northampton  hard-veined  slates  are  found  in  the  extensive  slate 
formation  known  as  the  Hudson  River  Division  of  the  lower  Silurian 
deposits ;  while  the  sl5te  formations  of  Vermont,  New  York  and 
Maine,  and  the  Peach  Bottom  region,  probably  belong  to  the  Cam- 
brian Division,  whose  place  in  the  geological  series  is  lower  and 
older  than  the  Silurian  rocks. 

.  ''The  slates  of  the  Cambrian  formation  are  usually  regarded  as 
better  in  respect  to  strength  and  weathering  qualities  than  those  of 
the  Silurian  age,  the  market  price  of  some  varieties  of  the  former 
being,  indeed,  more  than  double  that  of  the  common  kinds  of  the 
latter." 

245.  DESCRIPTION  AND  LOCAL  PRODUCTION  OF 
SLATES  FROM  DIFFERENT  STATES  AND  REGIONS.— 

VERMONT  AND  NEW  YORK  REGION.— In  the  western  portion  of 
Vermont  there  are  extensive  quarries  of  slate,  the  product  being  used  for  all 
the  different  purposes  for  which  the  material  is  adapted. 

Vermont  ranks  next  to  Pennsylvania  in  slate  production,  both  in  quan- 
tity and  value  of  roofing  slate,  producing  in  1906  29.15  per  cent  of  the 
quantity  of  roofing  slate.  Almost  the  entire  output  is  from  Rutland  County, 
in  the  vicinity  of  Castleton  and  West  Castleton,  Poultney.  Fair  Haven,  North 


*  For  further  data  regarding  the  production  of  slate  in  the  United  States  see  "Min- 
eral Resources  of  the  United  States,"  calendar  year  1906,  from  which  much  of  this  article 
is  taken. 


246 


BUILDING  CONSTRUCTION.    '        (Ch.  V) 


and  South  Poultney,  Hydeville,  Wells,  Pawlet  and  West  Pawlet,  with  a 
small  output  from  Northrteld,  Washington  County. 

The  stone  is  soft  and  uniform  in  texture,  and  can  be  readily  planed  or 
sawed  like  wood  with  a  circular  steel  saw. 

The  slates  from  this  region  vary  greatly  in  color,  and  are  classified  and 
sold  under  the  following  names : 

"Sea-green,"  "unfading  green,"  "uniform  green,"  "bright  green,"  "red," 
"bright  red,"  "purple,"  "variegated"  and  "mottled." 

The  true  "sea-green"  slate  is  found  in  this  State,  but  it  fades  and  changes 
color  badly. 

Red  Slate. — Nearly  all  the  red  slate  used  in  the  United  States  is  quarried 
in  the  neighborhood  of  Granville  and  Middle  Granville,  Washington  County, 
near  the  Vermont  line,  in  New  York  State.  "The  slates  of  this  formation 
are  of  a  brick-red  and  green  color,  both  varieties  often  occurring  in  the  same 
quarry."  The  slate  is  of  good  quality  and  is  used  almost  entirely  for  roofing 
purposes,  its  color  making  it  especially  desirable  for  fine  residences  and 
public  buildings.  Owing  to  the  limited  quantity,  this  slate  brings  about  three 
tij-nes  the  price  of  the  dark  slates. 

MAINE  REGION. — The  quarries  in  this  region  are  located  at  Monson, 
Elanchard  and  Brownville,  Piscataquis  County.  The  stone  is  of  a  blue-black 
color,  of  excellent  quality,  being  hard,  yet  splitting  readily  into  thin  sheets 
with  a  fine  surface.  The  slates  are  not  subject  to  discoloration,  and  give  forth 
a  clear  ringing  sound  when  struck.  The  Brownville  slate  is  said  to  be  the 
toughest  in  the  world.  Slate  from  this  quarry,  after  fifty  years*  exposure, 
looks  as  bright  and  clean  as  when  new.  • 

The  Maine  quarries  furnish  nearly  all  the  black  slates  used  in  New 
England.  The  product  is  also  extensively  used  for  school  slates,  blackboards 
and  sanitary  purposes. 

PENNSYLVANIA  SLATES.— Pennsylvania,  from  the  three  producing 
counties,  Northampton,  Lehigh  and  York,  produced  in  1906  62.13  per  cent  of 
the  slate  output  of  the  United  States.  Of  the  roofing  slate  the  number  of 
Squares  produced  in  Pennsylvania  represented  62.34  P^r  cent  of  the  quantity 
of  roofing  slate  produced  in  the  United  States.  Northampton  County  pro- 
duced 71.16  per  cent  of  the  Pennsylvania  output  and  44.28  per  cent  of  the 
total  for  the  United  States ;  Lejiigh  County  27.32  per  cent  of  the  Pennsylvania 
output  and  17  per  cent  of  the  total,  and  York  County  1.52  per  cent  of  the 
Pennsylvania  output  and  0.94  per  cent  of  the  total. 

The  number  of  squares  and  values  of  same  for  1906  by  counties  are  as 
follows : 


York  County  

Lehigh  County  

Northampton  County 


Squares. 
11,468 
206,505 
537,993 


Value. 
$59,833 
741  933 
1,908,483 


Totals 


755,966 


$2,710,249 


Bangor  Region. — This  region  is  entirely  within  Northampton  County,  and 
is  the  most  important,  in  point  of  production,  in  the  country.    The  princioal 


BUILDING  STONES— MISCELLAX ROUS, 


quarries  are  at  Bangor,  East  Bangor  and  Slatington.  The  color  is  a  uniform 
dark  blue  or  blue-black.  This  slate  is  used  very  extensively  for  blackboards 
and  school  slates,  as  well  as  for  roofing  purposes.  -The  average  modulus  of 
rupture  is  9,810  pounds  per  square  inch. 

The  Lehigh  region  includes  all  of  Lehigh  County,  a  few  quarries  in  Berks 
and  Carbon  Counties  and  regions  opposite  Slatington  in  Northampton  County. 
The  product  is  similar  to  that  of  the  Bangor  region. 

The  Pen  Argyl  region  embraces  quarries  at  Pen  Argyl  and  Wind  Gap  in 
Northampton  County. 

The  Northampton  hard-vein  region  includes  the  Chapman,  Belfast  and 
other  quarries,  all  in  Northampton  County.  This  region  is  distinguished  on 
account  of  the  extreme  hardness  of  the  slate  as  compared  with  that  pro- 
duced in  other  regions  of  the  State.  The  product  is  considered  the  best 
of  the  Silurian  slate,  its  extreme  hardness  being  generally  considered  an 
advantage,  rendering  it  durable  and  non-absorbent.  It  is  especially  suitable 
for  flagging.  The  average  modulus  of  rupture  is  about  8,480  pounds  per 
square  inch. 

PEACH  BOTTOM  REGION.— The  celebrated  "Peach  Bottom  Slate"  is 
taken  from  a  narrow  belt  scarcely  6  miles  long  and  a  mile  wide,  extending 
across  the  southeastern  portion  of  York  County  and  into  Harford  County, 
Maryland.  The  Maryland  slate  is  produced  at  Cardiff,  Harford  County,  a 
continuation  of  the  "Peach  Bottom"  region  at  Delta,  York  County,  Pa.  The 
stone  is  tough,  fine  and  moderately  smooth  in  texture,  blue-black  in  color, 
and  does  not  fade  on  exposure,  as  has  been  proven  by  seventy-five  years'  wear 
on  the  roofs  of  buildings.  It  also  ranks  very  high  for  strength  and  dura- 
bility, and  is  generally  considered  equal,  if  not  superior,  to  any  slate  in  the 
country.  The  average  modulus  of  rupture  of  twelve  specimens  was  11,260 
pounds,  the  lowest  value  being  8.320  pounds  per  square  inch. 

THE  NORTHERN  PENINSULA  OF  MIGHT GAN  contains  an  inex- 
haustible supply  of  good  roofing  slate,  and  quarries  were  at  one  time  worked 
about  15  miles  from  L'Anse  and  about  3  miles  from  Huron  Bay.  No  slate 
"  has  been  produced  from  there,  however,  since  1889.  "The  stone  here  is  sus- 
ceptible of  being  split  into  large,  even  slabs  of  any  desired  thickness,  with  a 
fine,  silky,  homogenous  grain,  and  combines  durability  and  toughness  with 
smoothness.    Its  color  is  an  agreeable  black  and  very  uniform."  * 

VIRGINIA.— A  good  blue-black  roofing  slate  is  quarried  commercially  at 
Arvonia,  Ore  Bank  and  Penlan,  Buckingham  County. 

GEORGIA. — Quarries  in  Polk  County,  Georgia,  furnish  most  of  the 
roofing  slates  for  Atlanta  and  neighboring  towns. 

OTHER  STATES. — Good  roofing  slate  is  found  also  in  other  States, 
but  the  quarries  have  not  been  recently  worked,  or  not  opened  at  all,  or  not 
worked  commercially  to  any  great  extent. 

7.    MISCELLANEOUS  BUILDING  STONES. 

264.    LAVA    STONE,    TUFFS    OR    TUFA.— Near  Castle 
Rock,  in  Colorado,  is  quarried  a  soft,  very  light  gray  and  pink  stone 


*  "Stones  for  Building  and  Decoration."    George  P.  Merrill. 


248  BUILDING   CONSTRUCTION.  (Ch.V) 

of  volcanic  origin,  which  is  commonly  called  ''lava  stone."  It  is 
extremely  light,  weighing  only  from  75  to  no  pounds  per  cubic 
foot,  and  it  can  be  cut  with  a  knife.  It  weathers  better  than  the 
soft  sandstones,  and  its  color  makes  it  very  suitable  for  rock-faced 
ashlar.  It  is  difficult  to  obtain  in  large  blocks,  and  is  full  of  clay  or 
air  holes  and  often  of  invisible  cracks,  which  render  it  dangerous 
for  use  in  heavy  buildings;  but  for  dwellings  it  makes  a  very  cheap, 
durable  and  pleasing  stone.  Owing  to  the  small  air  holes  which  it 
contains  it  does  not  receive  a  finished  surface,  and  is  most  effective 
when  used  in  rock-faced  work.  There  are  a  great  many  houses  and 
several  public  buildings  in  Denver  built  of  this  stone.  A  similar 
stone  occurs  in  the  vicinity  of  the  Las  Vegas  Hot  Springs  and 
Albuquerque,  New  Mexico. 

247.  BLUE  SHALE. — This  is  a  variety  of  sandstone  that  is 
dark  blue  in  color,  quite  dense  and  hard,  and  makes  a  fair  material 
for  foundations.  As  a  rule  it  does  not  work  readily  and  often  con- 
tains iron  pyrites,  which  render  it  unsuitable  for  ashlar  or  trim- 
mings. 

248.  TRAP. — The  only  stone  in  many  localities  is  a  hard,  igne- 
ous rock,  called  trap,  which  is  suitable  for  foundations,  but  cannot 
be  cut  easily.  Such  stones  are  used  for  local  purposes  only,  and 
when  none  other  can  be  obtained  except  at  great  expense. 

249.  SOAPSTONE. — Although  not  properly  a  building  stone, 
soapstone  is  used  more  or  less  in  the  fittings  of  buildings,  especially 
for  sinks  and  wash-trays. 

It  is  a  dark  bluish  gray  rock,  composed  essentially  of  the  mineral 
talc. 

It  is  soft  enough  to  be  cut  readily  with  a  knife,  or  even  with  the 
thumb  nail,  and  has  a  decided  soapy  feeling,  which  gives  it  its  name. 

Although  so  soft,  it  ranks  among  the  most  indestructible  and 
lasting  of  rocks.  At  present  its  chief  use  is  in  the  form  of  slabs 
about  inches  thick,  for  stationary  wash-tubs  and  sinks,  for  which 
it  is  one  of  the  best  materials.  Soapstone  also  offers  great  resistance 
to  heat,  and  is  often  used  for  lining  fireplaces. 

At  one  time  it  was  extensively  used  in  New  England  in  the  manu- 
facture of  heating-  or  warming-stones.  Considerable  quantities  of 
powdered  soapstone  are  used  for  making  slate-pencils  and  crayons, 
as  a  lubricant  for  certain  kinds  of  machinery,  and  in  the  finishing 
coat  on  plastered  walls. 


BUILDING  STONES—SELECTION. 


The  principal  quarries  producing  block  stone  are  situated  in  the 
States  of  New  Hampshire,  Vermont  and  Pennsylvania. 

The  State  of  North  Carolina  produces  most  of  the  powdered  soap- 
stone,  which  is  quarried  in  small  pieces  and  ground  in  a  mill.. 

8.    SELECTION  OF  BUILDING  STONES. 

250.  GENERAL  CONSIDERATIONS.— The  selection  of 
stones  for  structural  purposes  is  a  matter  of  the  greatest  impor- 
tance, especially  when  they  are  to  be  used  in  the  construction  of 
large  and  expensive  buildings.  The  cities  of  Northern  Europe  are 
full  of  failures  in  the  stones  of  important  structures,  and  even  in 
the  cities  of  the  northern  portion  of  the  United  States  the  examples 
of  stone  buildings  which  are  falling  into  decay  are  only  too 
numerous. 

'The  most  costly  building  erected  in  modern  times,  the  Parlia- 
ment House  in  London,  was  built  of  a  stone  taken  on  the  recom- 
mendation of  a  committee  representing  the  best  scientific  and  tech- 
nical skill  of  Great  Britain.  The  stone  selected  was  submitted  to 
various  tests,  but  the  corroding  influences  of  a  London  atmosphere 
were  overlooked.  The  great  structure  was  built  of  magnesian 
limestone,  and  now  it  seems  questionable  whether  it  can  be  made 
to  endure  as  long  as  a  timber  building  would  stand,  so  great  is  the 
effect  of  the  gases  of  the  atmosphere  upon  the  stone."  * 

Stone  should  be  studied  with  reference  to  its  hardness,  durability, 
beauty,  chemical  composition,  structure  and  resistance  to  crushing. 

251.  NEW  STONES. — If,  in  selecting  a  building  stone,  it  is 
deemed  advisable  to  use  one  from  a  new  quarry,  and  if  its  weather- 
ing qualities  have  not  been  tested  by  actual  use  in  buildings,  the 
architect  should  insist  upon  a  chemical  and  microscopic  test  by  an 
expert  to  see  if  there  is  anything  in  its  composition  or  structure 
which  would  render  it  unsuitable  for  building  purposes.  If  the 
.report  is  favorable,  and  if  the  stone  meets  the  tests  described  in 
the  following  sections,  he  may  then  use  it  with  a  free  conscience. 

An  architect  cannot  be  too  careful  about  using  a  new  stone,  or 
one  that  has  not  been  used  under  circumstances  similar  to  the  new 
ones ;  and  whenever  he  is  obliged  to  use  such  stone  he  should  take 
pains  to  obtain  as  much  information  in  regard  to  it  as  possible  front 
all  practical  sources. 

The  writer  has  known  of  a  case  in  which  a  certain  kind  of  stone, 


*  Ira  O.  Baker  in  "Masonry  Construction." 


250  BUILDING  CONSTRUCTION.  (Ch.V) 


which  had  for  a  long  time  been  used  for  making  ashlar,  was  used 
in  the  piers  under  a  seven-story  building.  The  piers  commenced  to 
crack  under  only  about  one-one-hundredth  part  of  the  breaking 
strength  as  given  in  a  published  report  of  strength  tests,  and  it 
cost  nearly  $200,000  to  repair  the  damage  and  to  substitute  other 
stone.  It  was  a  lava  stone,  and  its  failure  was  supposed  to  be  due 
to  fine  cracks  produced  in  blasting  out  the  stone  from  the  quarry. 

It  will  not  always  do,  either,  to  rely  upon  the  past  reputation  of 
a  stone  for  durability,  as  the  quality  of  one  building  stone  may 
differ  from  that  of  another  from  the  same  quarry. 

252.  CLIMATE  AND  LOCATION.— In  selecting  a  building 
stone  the  climate,  together  with  the  location,  with  especial  reference 
to  the  proximity  to  large  cities  and  manufacturing  establishments, 
should  be  first  considered.  There  are  many  porous  sandstones  or 
limestones  which  could  endure  an  exposure  of  hundreds  of  years 
in  a  climate  like  that  of  Florida,  New  Mexico,  Colorado  or  Arizona, 
but  which  would  be  sadly  disintegrated  at  the  end  of  a  single  sea- 
son in  one  of  the  Northern  States.  The  climate  of  our  Northern 
and  Eastern  States,  with  an  average  annual  precipitation  of  from 
30  or  40  inches  and  with  a  variation  in  temperature  sometimes 
reaching  120  degrees  Fahr.,  is  very  trying  to  stonework;  and  unless 
the  stones  used  are  suited  to  the  conditions  in  which  they  are  placed, 
they  are  liable  to  decay  and  utter  failure. 

253.  EFFECTS  OF  CHANGES  IN  TEMPERATURE.— The 
most  trying  conditions  to  which  building  stones  are  subject  are  the 
ordinary  changes  of  temperature  which  prevail  in  the  Northern  and 
Eastern  States.  "Stones,  as  a  rule,  possess  but  a  low  conducting 
power  and  slight  elasticity.  They  are  aggregates  of  minerals,  more 
or  less  closely  cohering,  each  of  which  possesses  degrees  of  expan- 
sion and  contraction  of  its  own.  As  temperatures  rise  each  and 
every  constituent  expands  more  or  less,  crowding  with  resistless 
force  against  its  neighbor;  as  the  temperatures  decrease  a  corre- 
sponding contraction  takes  place.  Since  the  temperatures  are  ever 
changing,  often  to  a  considerable  degree,  so,  within  the  mass  of  the 
stone,  there  is  continual  movement  among  its  particles.  Slight  as 
these  movements  may  be  they  can  but  be  conducive  of  one  result, 
a  slow  and  gradual  weakening  and  disintegration."  *  This  is  sup- 
posed to  be  the  chief  cause  of  the  disintegration  of  granites. 

There  are  several  examples  of  old  stonework  in  New  York  City 

*  "Stones  for  Building  and  Decoration."    George  P.  Merrill. 


BUILDING  STONES— SELECTION. 


25t 


in  which  the  stone  has  begun  to  decay  on  the  south  and  west  sides, 
where  the  sun  shines  the  longest,  but  in  which  it  has  not  begun  to 
decay  on  the  north  and  east  sides.  The  efforts  of  moderate  tem- 
peratures upon  stones  of  ordinary  dryness  are,  however,  shght 
compared  with  the  effects  of  freezing  upon  stones  saturated  with 
moisture.  The  pressure  exerted  by  water  in  passing  from  a  Hquid 
to  a  soHd  state  amounts  to  not  less  than  138  tons  to  the  square  foot; 
and  it  is,  therefore,  evident  that  any  porous  stone  exposed  to  heavy 
rains  and  to  a  temperature  several  degrees  below  the  freezing  point 
must  be  seriously  damaged  by  a  single  season's  exposure.  It  is  also 
evident  that  the  more  porous  a  stone  is  the  greater  will  be  the 
deterioration ;  and  as  sandstones  are  the  most  porous  of  all  building 
stones,  they  suffer  the  most  from  this  cause  and  granites  suffer  the 
least.  Granite  is,  accordingly,  the  best  stone  for  a  base-course  '^r 
for  vmderpinning. 

For  the  effect  of  absorption  on  the  durability  of  stones  see 
Article  263. 

254.  DURABILITY  OF  DIFFERENT  STONES.— The  dur- 
ability of  a  stone  is  naturally  of  the  first  importance ;  for  unless  it 
lasts  a  reasonable  length  of  time,  the  money  spent  on  a  structure 
will  be  largely  wasted.  All  public  buildings  should  be  built  of 
materials  practically  imperishable. 

Table  XXIII,  taken  from  the  Report  of  the  Tenth  Census,  1880, 
Vol.  X,  p  391,  gives  the  number  of  years  that  different  stones 
have  been  found  to  last  in  New  York  City,  without  discoloration  or 
disintegration  to  the  extent  of  necessitating  repairs : 


TABLE  XXIII. 
Durability  of  Different  Stones. 


c 


Coarse  brownstone.  .   

Fine  laminated  brownstone  

Compact  brownstone  

Bluestone  (sandstone),  untried  , 

Nova  Scotia  sandstone,  untried  

Ohio  sandstone  (best  siliceous  variety), 


  5  to  15 

,   20  to  50 

  100  to  200 

Probably  centuries 
.Perhaps  50  to  200 


Perhaps  from  one  to  many  centuries 


Coarse  fossiliferous  limestone.. 
Fine  oolitic  (French)  limestone. 

Marble,  coarse  dolomite  

Marble,  fine  dolomite  

Marble,  fine  

Granite  

Gneiss  


50  years  to  many  centuries 


60  to  80 
50  to  100 
75  to  200 


20  to  40 
30  to  40 


'  40 


252 


BUILDING  CONSTRUCTION. 


(Ch.V) 


There  are  many  circumstances  and  conditions,  aside  from  the 
quaHty  of  the  stone,  that  affect  the  durabihty  of  exposed  stone- 
work, the  more  important  of  which  are  heat  and  cold,  composition 
of  the  atmosphere,  position  of  the  stone  in  the  building,  and  manner 
of  dressing  the  stone; 

255.  EFFECT  OF  ATMOSPHERIC  ACTION  ON  BUILD- 
ING STONES. — The  chemical  action  of  the  gases  of  the  atmos- 
phere, when  brought  by  rain  in  contact  with  the  surfaces  of  certain 
ston'es,  seriously  affects  their  durability.  The  most  important 
changes  produced  by  these  agencies  are  (i)  oxidation  and  (2) 
solution. 

(1)  Oxidation. — The  process  of  oxidation  is,  as  a  rule,  confined 
to  those  stones  which  contain  some  compound  of  iron,  and  par- 
ticularly that  known  as  pyrite  or  iron  disulphide.  If  the  iron  exists 
in  the  latter  form  it  generally  combines  with  the  oxygen  of  the  air, 
forming  the  various  oxides  and  carbonates  of  iron,  such  as  are 
popularly  known  as  ''rust." 

^Tf  the  sulphide  occurs  scattered  in  small  particles  throughout  a 
sandstone  the  oxide  is  disseminated  more  evenly  through  the  mass 
of  the  rock,  and  aside  from  a  slight  yellowing  or  mellowing  of  the 
color,  as  in  certain  Ohio  sandstones,  it  does  no  harm.  Indeed,  it 
may  result  in  positive  good,  by  supplying  a  cement  to  the  individual 
grains  and  thus  increasing  the  tenacity  of  the  stone."* 

If  the  pyrite  exists  in  pieces  of  any  size,  however,  it  is  almost 
sure  to  oxidize  and  stain  the  stone  so  as  to  ruin  its  appearance,  # 
especially  if  it  is  of  a  light  color. 

In  all  stones  other  than  sandstones  the  presence  of  any  pyrite  is 
a  very  serious  defect,  as  it  is  almost  sure  to  rust  them  and  may  also 
render  them  porous  and  more  liable  to  the  destructive  effects  of 
frost. 

(2)  Solution. — The  worst  effect  of  the  action  of  the  gases  of 
the  atmosphere  in  connection  with  rain  is  the  dissolving  of  certain 
constituents  of  stones,  thereby  causing  their  decomposition.  Pure 
water  alone  is  practically  without  effect  on  all  stones  used  for  build- 
ing, but  hi  large  cities,  and  particularly  in  those  in  which  a  great 
deal  of  coal  is  consumed,  the  rain  absorbs  appreciable  quantities  of 
sulphuric,  carbonic  and  other  acids  from  the  air,  conveys  them  into 


*  "Stones  for  Buildins:  and  Decoration."    George  P.  Merrill. 


BUILDING  STONES— SELECTION. 


253 


the  pores  of  the  stones  and  very  soon  destroys  those  whose  con- 
stituents are  Hable  to  be  decomposed  by  such  acids. 

Carbonate  of  h'me  and  carbonate  of  magnesia,  the  principal  con- 
stituents of  ordinary  marbles,  limestones  and  dolomites,  are  particu- 
larly affected  by  the  solvent  action  of  these  acids,  even  when  they 
are  present  only  in  very  minute  quantities ;  and  on  this  account  these 
stones  are  extremely  perishable  in  large  cities  and  manufacturing 
towns.  Of  course  in  dry  climates  the  acids  are  not  conveyed  into 
the  stone  to  any  great  extent,  and  the  stones  last  much  longer  than, 
they  do  in  a  damp  climate.  The  less  absorbent  a  stone  is  the  less 
•  will  be  the  solvent  action  of  the  acids,  and  the  longer  it  will  last. 
Dolomites  are  in  this  respect  more  durable  than  limestones. 

Sandstones,  whose  cementing  material  is  composed  largely  of  iron 
or  lime,  are  also  subject  to  rapid  decay  through  the  solvent  action 
of  the  acidulated  rains.  The  feldspars  of  granites  and  other  rocks 
are  also  responsive  to  the  same  influence,  though  in  a  less  degree. 

256.  METHOD  OF  FINISHING  BUILDING  STONES.— 
This  also  has  a  great  deal  to  do  with  the  durability  of  a  stone.  As 
a  rule,  the  less  jar  from  heavy  pounding  that  the  surface  is  sub- 
jected to  the  more  durable  will  be  the  surface,  for  the  reason  that 
the  constant  impact  of  the  blows  tends  to  destroy  the  adhesive  or 
cohesive  power  of  the  grains,  and  thus  renders  the  stone  more  sus- 
ceptible to  atmospheric  influences.  This  applies  particularly  to 
granites  and  limestones.  Only  granites  and  the  hardest  sandstones 
should  be  pene-  or  bush-hammered ;  all  others,  if  dressed,  should 
be  cut  with  a  chisel.  Sandstones  may  afterward  be  finished  with  a 
crandall,  if  desired.  For  granites  a  rock-face  surface  is  probably 
the  most  durable,  since  the  crystalline  facets  thus  exposed  are  best 
fitted  to  shed  moisture  and  the  natural  adhesion  of  the  grains  is  not 
disturbed.  For  ail  other  stones,  however,  a  smoothly  sawn,  rubbed 
or  polished  surface  seems  best  adapted  to  a  variable  climate. 

257.  MANNER  OF  SETTING  STONES.— When  a  stone  is 
built  into  the  wall  of  a  building  in  such  a  way  that  the  natural  lay- 
ers of  the  stone  are  vertical,  or  on  edge,  the  water  penetrating  the 
stone  and  freezing  there  causes  its  surface  to  exfoliate  or  peel  off 
much  more  quickly  and  to  a  much  greater  extent  than  is  the  case 
when  it  is  laid  with  its  natural  bed  horizontal. 

Stones  also  so  placed  in  a  building  that  rain  strikes  them  and 
washes  over  them,  such  as  sills,  belt-courses,  etc.,  decay  sooner  than 


254 


BUILDING  CONSTRUCTION. 


(Ch.V) 


the  ashlar  forming  the  face  of  the  wall,  and  should  be  of  the  rnosf 
durable  material. 

258.  THE  COLOR  OF  STONES.— The  great  governing  point 
with  an  architect  in  selecting  a  building  stone  is  generally  its  color. 
In  this  again  he  is  limited  to  a  choice  between  those  stones  which 
come  within  the  limit  of  cost.  But  the  question  of  durability  should 
always  be  borne  in  mind.  Architects,  owners  and  contractors  should 
always  keep  in  mind  not  only  how  a  building  will  look  when  just 
completed,  but  how  it  will  appear  at  the  end  of  a  few  years,  and, 
again,  at  the  end  of  half  a  century.  And  probably  it  is  better  to 
accept  shades  of  color  which  may  be  a  little  harsh  and  inharmonious 
at  first,  if  durability  is  gained  thereby,  than  to  use  the  most  pleasing 
color  only  to  see  it  entirely  changed  at  the  end  of  a  year,  and 
crumbled  to  pieces  at  the  end  of  a  decade. 

A  durable  stone  of  any  color  generally  tones  down  and  becomes 
more  pleasing  at  the  end  of  a  few  years,  while  one  that  is  not 
durable  and  permanent  in  color  very  soon  becomes  an  eyesore. 

In  the  country  and  in  small  towns  where  there  is  no  manufactur- 
ing, and  where  little  bituminous  coal  is  used,  light-colored  stones 
may  be  used  with  the  prospect  of  having  their  color  remain  un- 
changed ;  but  in  large  cities  and  manufacturing  towns,  and  particu- 
larly in  those  in  which  bituminous  coal  is  the  principal  fuel,  light 
stones  should  be  avoided.  For  the  last-mentioned  localities  red  or 
brown  siliceous  sandstones  are  the  most  enduring  and  permanent, 
and  next  to  these  come  the  granites. 

In  cities  like  Chicago,  St.  Louis,  Pittsburg,  Cincinnati,  etc.,  the 
darker  the  stone  used  the  more  permanent  will  be  its  color,  that  is, 
in  the  central  portions  of  the  cities,  as  both  brick  and  stone  assume  a 
dirty,  dark  bronze  color  in  a  few  years,  and  in  such  localities  deli- 
cate colors  and  fine  carving  are  out  of  place. 

In  climates  like  that  of  Colorado,  Arizona  and  New  Mexico,  where 
there  is  a  very  bright  sun  and  almost  no  rain,  the  light  stones,  and 
particularly  the  marbles,  are  most  effective,  as  the  shadows  on  such 
stones  are  very  marked,  and  all  kinds  of  ornament  are  made  much 
more  prominent  than  on  red  or  dark  stones.  Any  compact  stone 
will  last  for  centuries  above  the  ground. 

As  a  rule,  other  things  being  equal,  those  stones  which  hold  their 
native  color  the  best  will  be  the  most  beautiful  in  a  building;  and 


BUILDING  STONES— SELECTION. 


255 


of  the  stones  which  do  change  color,  those  will  be  the  most  desir- 
able which  change  the  least  and  the  most  evenly. 

259.  THE  COST  OF  BUILDING  STONES.— This  has  often 
more  to  do  with  the  choice  of  a  building  stone  by  the  owner  than 
the  architect  wishes.  The  cost  of  a  stone  when  cut  depends  not 
only  upon  the  cost  of  the  rough  stone  delivered  at  the  site,  but  also 
upon  the  ease  with  which  it  may  be  worked ;  upon  whether  it  is 
to  be  smooth  or  rock-face ;  plain  or  moulded ;  and  also,  to  some 

extent,  upon  its  weight.    One  stone  may  be  cheaper  than  another  « 
in  the  rough,  but  the  extra  labor  of  cutting  may  make  it  the  more 
expensive  when  built  into  the  wall.    The  heavier  a  stone  is  the 
greater  will  be  the  cost  of  setting  and  of  transportation. 

260.  THE   HARDNESS   OF  'BUILDING    STONES.— For 
many  purposes  the  hardness  of  a  stone  must  be  considered,  as,  for 
example,  when  it  is  to  be  used  for  steps,  door  sills,  paving,  etc. 
Granites,  quartzites,  or  siliceous  sandstones,  and  bluestones  are  the  ■ 
best  for  this  purpose. 

261.  THE  STRENGTH  OF  BUILDING  STONES.— When- 
ever any  kind-  of  stone  is  to  be  used  for  foundations,  piers,  lintels, 
or  bearing-stones,  etc.,  its  strength  should  be  considered,  and  if  this 
has  not  been  demonstrated  to  be  sufficient  by  practical  use  under 
similar  circumstances,  cubes  of  the  stone  measuring  about  6  inches 
on  a  side  should  be  carefully  tested  for  the  crushing  strength.  If 
it  has  every  appearance  of  being  a  first-clasS  stone  of  its  kind,  its 
strength  may  be  assumed  to  be  equal  to  the  average  strength  of 
stones  of  that  kind.  The  safe  working  strength  for  piers,  etc., 
should  not  exceed  one-tenth  of  the  crushing  strength.  Tables  giving 
the  crushing  strength  of  many  well-known  stones  and  the  safe 
working  strength  for  stone'  masonry  are  given  in  the  Appendix. 

The  method  according  to  which  a  stone  is  quarried  sometimes 
has  much  to  do  with  its  strength.  If  it  is  quarried  by  means  of 
explosives  it  may  contain  minute  cracks,  which  cannot  .  be  dis- 
covered until  it  receives  its  load,  when  their  presence  is  unpleasantly 
manifested.  Such  an  occurrence  could  take  place  only  in  some  stone 
like  a  lava  or  a  conglomerate.  The  cracking  and  splitting  of  stones 
in  buildings  are  due  more  often  to  imperfect  setting  than  to  lack  of 
strength  in  the  stones  themselves.  All  stones  that  will  meet  the 
requirements  for  durability  will  have  sufficient  strength  for  all  pur- 
poses, except  when  they  are  in  the  positions  mentioned  above. 


256  BUILDING  CONSTRUCTION.  (Ch,V) 

262.  FIRE  RESISTANCE  OF  BUILDING  STONES.^— The 
property  in  a  stone  of  resisting  the  action  of  fire  is  often  of  much 
consequence,  especially  when  there  is  exposure  to  fire  risks  on  all 
sides,  as  is  the  case  with  most  business  blocks.  Of  the  different 
kinds  of  stone  used  for  building,  the  compact,  fine-grained  sand- 
stones withstand  the  action  of  fire  the  best ;  limestones  and  marbles 
suffer  the  most,  being  calcined  by  an  intense  heat;  and  granites  are 
intermediate  in  regard  to  injurious  effects.  The  best  sandstones 
generally  come  out  uninjured,  with  the  exception  of  the  discolora- 
tion caused  by  smoke.  Granites  do  not  always  collapse,  but  the  face 
of  the  stone  generally  splits  off  and  flies  to  pieces,  often  with  ex- 
plosive violence. 

9.    TESTING  OF  BUILDING  STONES. 

263.  GENERAL  CONSIDERATIONS.— Every  stone  intended 
for  building  purposes  that  does  not  come  from  some  well-known 
quarry  should  be  tested  by  chemical  analysis  and  the  results  com- 
pared with  the  analysis  of  well-known  stones  of  the  same  kind ;  and 
if  found  to  differ  materially  in  those  constituents  which  are  soluble 
in  water  or  attacked  by  sulphuric  or  carbonic  acids  it  should  be 
rejected.  The  presence  also  of  iron  pyrites  should  lead  to  the  re- 
jection of  the  stone  if  it  is  intended  for  exterior  use.  If.  the  build- 
ing is  one  of  importance  the  architect  should  insist  on  the  owners 
getting  the  opinion  of  some  expert  chemist  or  mineralogist  on  the 
durability  and  weathering  qualities  of  the  stone  in  question. 

As  a  rule,  however,  most  buildings  are  now  built  with  stone  which 
is  taken  from  well-known  quarries,  and  whose  weathering  qualities 
have  been  tested ;  so  that  if  the  quality  is  equal  to  the  best  that  the 
quarry  will  supply,  the  ston-e  will  prove  all  that  was  expected  of  it. 
The  fact,  however,  that  certain  quarries  have  furnished  good 
material  in  the  past  is  no  guarantee  of  the  future  output  of  the 

*  For  recent  and  valuable  data  on  the  fire  resistance  of  building  stones  the  reader 
is  referred  to  the  very  interesting  paper  by  W.  E.  McCourt,  on  "The  Fire-Resisting  Quali- 
ties of  Some  New  Jersey  Building  Stones,  Part  I,"  in  "The  Annual  Report  of  the  State 
Geologist  for  1906." 

Mr.  McCourt  collected  a  number  of  samples  of  New  Jersey  stones  during  the  summers 
of  1904  and  1905,  under  the  direction  of  the  State  Geologist,  and  these  were  tested  in  the 
Geological  Laboratory  of  Cornell  University,  in  connection  with  work  for  advanced 
degrees.  The  object  of  the  investigation  was  to  ascertain  the  relative  tendency  of  various 
stones  to  withstand  extreme  heat,  and  to  determine,  as  far  as  possible,  the  criteria  which 
control  the  refractory  properties. 

The  report  includes  an  outline  of  earlier  investigations,  observations  on  burned  build- 
ings, methods  of  making  the  fire  tests,  samples  tested,  general  summary  of  results  with 
granites  and  gneisses,  diabases,  sandstones,  limestones  and  argillite,  and  a  detailed  state- 
ment of  experiments,  with  nnmerous  illustrations. 

The  reader  is  referred  also  to  the  Appendix. 

f 


BUILDING  STONES— TESTING. 


257 


entire  quarry.  This  is  especially  true  regarding  rocks  of  sedimen- 
tary origin,  like  the  sandstones  and  limestones,  different  beds  of 
which  will  often  vary  widely  in  color,  texture,  composition  and  dur- 
ability, although  lying  closely  adjacent.  In  many  quarries  ^f  cal- 
careous rocks  in  Ohjo,  Iowa  and  neighboring  States  the  product  is 
found  to  vary  at  different  depths,  all  the  way  from  pure  limestone 
to  magnesian  limestone  and  dolomite,  and  in  many  cases  an  equal 
variation  exists  in  point  of  durability.* 

The  architect  should,  therefore,  make  a  careful  examination  of  the 
stone  as  it  is  delivered  on  the  ground,  or  in  the  yard  and  before  it  is 
cut,  to  see  that  the  quality  of  the  stone  is  up  to  the  standard  re- 
quired ;  and  in  large  buildings  in  which  a  great  quantity  is  required 
.it  is  advisable  to  visit  the  quarry  and  to  determine  from  what  part 
of  it  the  stone  shall  be  taken. 

The  following  rules  and  tests  will  enable  one  to  judge  if  a  stone 
is  of  good  quality  and  likely  to  prove  durable : 

Compactness. — As  a  general  rule,  in  comparing  stones  of  the  saifle 
class,  the  least  porous,  most  dense  and  strongest  will  be  the  most 
durable  in  atmospheres  which  have  no  special  tendency  to  attack 
their  constituent  parts.  Good  building  stones  should  also  give  out 
a  clear,  ringing  sound  when  struck  with  a  hammer. 

Fracture. — A  fresh  fracture,  when  examined  through  a  powerful 
magnifying  glass,  should  be  bright,  clean  and  sharp,  with  the  grains 
well  cemented  together.  A  dull,  earthy  appearance  indicates  stone 
likely  to  decay. 

Absorption. — One  of  the  most  important  tests  for  the  durability 
of  stone  is  that  of  the  porosity  or  degree  to  which  it  absorbs  mois- 
ture ;  since,  other  things  being  equal,  the  less  moisture  it  absorbs 
the  more  durable  it  will  be. 

To  determine  the  absorbent  power  the  specimen  is  thoroughly 
dried  in  a  temperature  of  about  100  degrees  Fahr.,  and  carefully 
weighed ;  then  soaked  for  at  least  twenty-four  hours  in  pure  water ; 
then  removed  from  the  water,  and  the  surface  allowed  to  dry  in  the 
air ;  and  then  weighed.  The  increase  in  weight  is  the  amount  of 
water  absorbed,  and  stands,  although  not  absolutely  correct,  as  an 
expression  of  the  stone's  absorbent  power.  This  test  is  extremely 
simple,  and  when  done  with  care  gives  very  practical  results. 

Any  stone  which  absorbs  10  per  cent  of  its  weight  of  water  dur- 


*  "Stones  for  Building  and  Decoration."    George  P.  Merrill. 


258 


BUILDING  CONSTRUCTION.  (Ch.V) 


ing  twenty-four  hours  should  be  looked  upon  with  suspicion  until, 
by  actual  experiment,  it  shows  itself  capable  of  withstanding,  with- 
out harm,  the  different  effects  of  the  weather  for  several  years. 
Half  %i  this  amount  may  be  considered  too  large  when  the  stone 
contains  any  appreciable  amount  of  lime  or  clayey  matter.* 

The  porosity  of  a  stone  also  has  an  effect  upon  its  appearance 
when  in  a  building. 

A  non-absorbent  stone  is  washed  clean  by  each  heavy  rain,  and 
its  original  beauty  is  retained ;  while  a  porous  stone  soon  fills  with 
dirt  and  smoke  and  looks  little  better  than  a  stone  plastered  with 
cements.  Even  in  stones  for  interior  decoration  absorption  should 
not  be  overlooked,  as  ink,  oils  or  drugs  may  ruin  expensive  furnish- 
ings if  the  stones  used  are  porous. 

Acid  Test.-\ — Simply  soaking  a  stone  for  some  days  in  dilute 
solutions  containing  i  per  cent  of  sulphuric  acid  and  hydrochloric 
acid  will  afford  a  rough  idea  as  to  whether  or  not  it  will  stand  a 
city  atmosphere.  A  drop  or  two  of  acid  on  the  surface  of  the  stone 
will  create  an  intense  effervescence  if  there  is  a  large  proportion 
present  of  carbonate  of  lime  or  carbonate  of  magnesia. 

Test  for  Solution —The  following  simple  test  is  useful  for  deter- 
mining whether  a  stone  contains  much  easily  dissolved  earthy  or 
mineral  matter: 

Pulverize  a  small  piece  of  the  stone  with  a  hammer,  and  put  the 
pulverized  portion  into  a  glass  filled  about  one-third  with  clear  water, 
and  let  it  remain  undisturbed  for  at  least  half  an  hour.  Then  agitate 
the  water  and  broken  stone  by  giving  the  glass  a  circular  motion 
with  the  hand.  If  the  stone  is  highly  crystalline,  and  the  particles 
well  cemented  together,  the  water  will  remain  clear  and  transparent ; 
but  if  the  specimen  contains  uncrystallized  earthy  powder  the  water 
Vv^ill  present  an  appearance  more  or  less  turbid  or  milky,  depending 
upon  the  quantity  of  loose  matter  contained  in  the  stone. 

10.    SEASONING  OF  STONE. 

264.  GENERAL  CONSIDERATIONS.— All  stone  is  better  for 
being  exposed  to  the  air  before  it  is  set  until  it  becomes  dry.  This 
gives  a  chance  for  the  quarry  water  to  evaporate,  and  in  nearly  all 


*  "Stones  for  Building  and  Decoration."  .George  P.  Merrill, 
t  "Notes  on  Building  Construction,"  Part  III,  p.  11. 


BUILDING  STONES—SEASONING— PROTECTION  259 


cases  renders  the  stone  harder,  and  prevents  it  from  spHtting  from 
the  action  of  the  frost. 

Many  stones,  particularly  certain  varieties  of  sandstones  and  lime- 
stones which  are  quite  soft  and  weak  when  first  quarried,  acquire 
considerable  hardness  and  strength  after  they  have  been  exposed  to 
the  air  for  several  months.  The  following  is  supposed  to  be  the 
cause  of  this  hardness.  The  quarry-water  contained  in  the  stone 
holds  in  solution  a  certain  amount  of  cementing  material,  which,  as 
the  water  evaporates,  is  deposited  between  the  particles  of  sand, 
binding  them  more  firmly  together  and  forming  a  hard  outer  crust 
to  the  stone,  while  the  inside  remains  soft,  as  at  first.  On  this 
account  the  stone  should  be  cut  soon  after  it  is  taken  from  the 
quarry,  and  if  any  carving  is  to  be  done  it  should  be  done  before 
the  stone  becomes  dry,  otherwise  the  hard  crust  will  be  broken  ofif 
and  the  carving  will  be  on  the  soft  interior,  and  consequently  have 
its  durability  much  impaired. 

II.    PROTECTION  AND  PRESERVATION  OF 
STONEWORK. 

265.  GENERAL  CONSIDERATIONS.— There  are  a  great 
many  preparations  that  have  been  used  for  preventing  the  decay 
of  building  stones,  but  all  are  expensive,  and  none  have  proved 
entirely  satisfactory. 

Paint. — One  material  very  generally  used  for  preserving  stone- 
work is  lead  and  oil  paint.  This  is  effectual  for  a  time,  but  the  paint 
is  destroyed  by  the  atmospheric  influences,  and  must  be  renewed 
every  three  or  four  years.    It  also  spoils  the  beauty  of  the  stone. 

The  White  House  at  Washington  is  built  of  a  porous  red  sand- 
stone, which  has  been  painted  white  for  many  years. 

Oil. — Boiled  linseed  oil  is  sometimes  used  on  stonework,  but  it 
always  discolors  a  light-colored  stone,  and  renders  a  dark-colored 
one  still  darker.  "The  oil  is  applied  as  follows :  The  surface  of  the 
stone  is  washed  clean,  and,  after  drying,  is  painted  with  one  or  more 
coats  of  boiled  linseed  oil,  and  finally  with  a  weak  solution  of 
ammonia  in  warm  water.  This  renders  the  tint  more  uniform.  This 
method  has  been  tried  on  several  houses  in  New  York  City,  and  the 
waterproof  coating  thus  produced  found  to  last  about  four  or  five 
years,  when  it  must  be  renewed.  The  preparation  used  in  coating 
the  Egyptian  obelisk  in  Central  Park  is  said  to  have  consisted  of 
paraffine  containing  creosote  dissolved  in  turpentine,  the  creosote 


26o 


BUILDING  CONSTRUCTION. 


(Ch.V) 


being  considered  efficacious  in  preventing  organic  growth  upon 
the  stone.  The  melting  point  of  the  compound  is  about  140  degrees 
Fahr.  In  applying  the  preparation  the  surface  to  be  coated  is  first 
heated  by  means  of  specially  designed  lamps  and  charcoal  stoves, 
and  the  melted  compound  applied  with  a  brush.  On  cooling  it  is 
absorbed  to  a  depth  dependent  upon  the  degree  of  penetration  of 
the  heat.  In  the  case  of  the  obelisk  the  depth  was  about  ^  of  an 
inch.''''' 

A  soap  and  alum  solution  also  has  been  used  with  moderate  suc- 
cess for  rendering  stone  waterproof. 

Ransome's  Process. — This  consists  in  applying  a  solution  of  sili- 
cate of  soda  or  potash,  water-glass,  to  the  surface  of  the  stone,  after 
it  has  been  cleaned,  with  a  whitewash  brush  until  its  surface  has 
become  saturated.  After  it  has  become  dry  a  solution  of  chloride 
of  calcium  is  freely  applied  so  as  to  be  absorbed  with  the  silicate 
into  the  structure  of  the  stone..  The  two  solutions  produce  by 
double  decomposition  an  insoluble  silicate  of  lime,  which  fills  the 
pores  of  the  stone  and  binds  its  particles  together,  thus  increasing 
both  its  strength  and  weathering  qualities.  This  process  has  been 
used  to  a  considerable  extent  in  England,  and  is  perhaps  the  most 
successful  of  all  applications.  The  process  of  applying  the  solutions 
is  more  fully  described  in  "Notes  on  Building  Construction,"  Part 
III,  p.  78. 

^       12.    ARTIFICIAL  AND  MANUFACTURED  STONES. 

266.  GENERAL  DESCRIPTION.— A  brief  mention  is  made 
here  of  the  so-called  "artificial  stones"  and  "manufactured  stones,'' 
although  it  may  be  claimed  that  they  belong  more  properly,  in  any 
strict  classification,  to'  such  products  as  hydraulic  cement  products, 
sand-lime  products,  etc. 

Artificial  cement  stones  are  usually  carefully  made  blocks  of 
cement  mortar  rendered  compact  by  ramming  or  compressing  such 
mortar  in  the  moulds,  and  given  any  desired  .shape  by  using  suitable 
moulds.    To  this  class  belongs  the  "P>eton  Coignet,"  used  in  France. 

An  artificial  stone,  made  by  a  diflferent  process,  is  called  *'Ran- 
some  Stone."  The  mortar  is  made  of  sand,  silicate  of  soda  and 
water,  arid  is  compressed  into  m.oulds  in  the  usual  way.  A  hot  solu- 
tion of  calcium  chloride  is  then  provided,  into  which  the  stone  is 


*  "Stones  for  Building  and  Decoration."    George  P.  Merrill, 


BUILDING  STONES— ARTIFICIAL— MANUFACTURED  261 


immersed  under  pressure,  causing  a  calcium  silicate  to  form,  and 
resulting  in  an  insoluble  cement,  and  also  in  a  sodium  chloride, 
which  latter  is  removed  by  washings. 

Several  kinds  of  artificial  stone  are  manufactured  under  patented 
processes,  and  many  are  combinations  of  hydraulic  cement,  sand, 
pebbles,  stone-dust,  etc.,  with  or  without  the  addition  of  some  in- 
durating material,  as  baryte,  letharge,  etc.  They  are  manufactured 
either  in  place  or  in  the  form  of  blocks  at  the  factories. 

To  several  of  the  sand-lime  products  the  name  "manufactured 
stone"  has  been  given  by  the  manufacturers.  A  product,  consisting 
essentially  of  silica  and  lime,  is  in  England  called  "silicate  stone." 
The  proportion  of  lime  used  is  from  5  to  10  per  cent,  the  purity 
of  the  silica  regulating  the  quantity. 

A  sand-lime  product  is  manufactured  at  Wilmington,  Delaware, 
by  the  Diamond  Stone-Brick  Company,  and  called  ''Wawaset  Lime- 
stone." The  manufacturers  claim  that  the  principle  underlying  its 
production  has  been  successful  for  about  twenty  years,  but  that  its 
application  has  not  been  made  commercial  until  recently.  The 
process  is  a  secret,  but  it  is  admitted  that  it  contains  no  cement 
whatever,  and  that  it  is  along  the  lines  of  those  employed  in  the 
manufacture  of  sand-lime  bricks.  If  the  sand-lime -brick  theory  is  a 
correct  one,  and  there  seems  to  be  strong  evidence  that  it  is,  then 
this  material,  supplied  on  a  large  scale,  should  be  good,  providing 
the  process  can  be  so  well  carried  out  that  large  stones  are  thor- 
oughly permeated  the  same  as  are  small  bricks. 

Quite  elaborate  tests  have  been  made  on  these  products,  and  very 
satisfactory  results  shown,  not  only  when  considered  in  relation  to 
the  manufactured  stones  themselves,  but  also  when  com^pared  with 
the  results  of  comparative  tests  made  with  natural  limestones,  sand- 
stones, etc. 

The  Wawaset  manufactured  limestone  has  been  used  in  several 
buildings  for  both  exterior  and  interior  purposes  and  lends  itself 
well  to  carved,  moulded  and  decorative  work  of  all  kinds.  It  was 
used  in  the  Spring  Garden  Street  Branch  Library  building  in  Phil- 
adelphia, and  in  other  buildings  in  the  same  city  and  in  Wilmington, 
Delaware. 

In  regard  to  the  products  including  hydraulic  cement  mortar  and 
concrete  constructive  and  decorative  stones  there  are  a  number  of 
companies  making  them  in  different  parts  of  the  United  States.  At 
New  Haven,  Conn.,  the  Economy  Manufacturing  Company  makes 


262 


BUILDING  CONSTRUCTION.  (Ch.V) 


a  concrete  building  stone,  the  process  involved  in  which  is  without 
secrets  or  patents,  and  consists  in  the  pouring  of  crushed  trap  rock 
and  cement  into  a  form,  letting  it  stay  there  about  two  days,  and 
then  rubbing  it  down  in  various  ways.  It  is  entirely  similar  to  the 
concrete  used  in  footings  and  foundations,  except  that  it  has  about 
three  times  the  amount  of  cement  usually  put  into  the  latter  con- 
structions, and  is  mixed  with  much  greater  care. 

The  artificial  concrete  stone  products  of  this  company  have  been 
used  in  several  important  buildings,  such  as  the  new  Cadet  Bar- 
racks at  West  Point,  N.  Y. ;  Christ  Church,  West  Haven,  Conn. ; 
Trinity  Church,  New  Haven,  Conn. ;  St.  Philip's  Church,  Durham, 
N.  C. ;  St.  James'  Church,  Woodstock,  Vt.,  etc^ 


Chapter  VI. 


Cut-stonework. 


267.  INTRODUCTORY.— In  order  to  properly  lay  out,  detail 
and  specify  the  stonework  of  a  building-,  it  is  necessary  to  have  a 
thorough  knowledge  of  the  different  tools  and  processes  employed 
in  cutting  and  dressing  the  stone  and  of  the  different  ways  in  which 
stone  is  used  for  walls,  ashlar  and  trimmings. 

The  description  in  this  chapter  of  different  classes  of  work,  sup- 
plemented by  critical  observation  in  the  stone-yard  and  at  the  build- 
ing, should  give  one  a  good  idea  of  the  ordinary  methods  and 
practices  employed  in  this  country. 

The  subject  of  cut-stonework  may  be  conveniently  discussed  under 
seven  subdivisions,  as  follows : 

1.  Classes  of  Cut-stonework. 

2.  Stone-cutting  and  Finishing. 

3.  Miscellaneous  Trimmings. 

4.  Treatment  of  Cut-stonework  in-  the  Wall. 

5.  Strength  of  Cut-stonework. 

6.  Measurements  and  Cost  of  Cut-stonework. 

7.  Superintendence  of  Cut-stonework. 

I.    CLASSES  OF  CUT-STONEWORK.  - 

Stonework,  such  as  is  used  in  the  superstructure  of  buildings, 
may  be  divided  into  three  classes :  Rubble-work,  Ashlar  and  Trim- 
mings. 

268.  RUBBLE-WORK. — This  is  used  only  for  exterior  walls 
in  places  where  suitable  stone  for  cutting  cannot  be  obtained  at  a 
relatively  low  price.  There  are  localities  which  furnish  cheap,  dur- 
able stone  which  cannot  be  easily  cut,  such  as  the  conglomerates 
and  slate  stones.  They  generally  split  so  as  to  give  one  good  face, 
and  may  be  used  with  good  effect  for  walls,  with  cut-stone  or  brick 
trimmings. 

Fig.  93  shows  the  usual  method  of  building  a  rubble  wall  above 
ground.  After  the  wall  is  up  the  joints  are  generally  filled  flush 
with  mortar  of  the  same  color  as  the  stone,  and  a  raised  false  joint 

263 


264 


B  UILDING  CONSTRUCTION. 


(Ch.  VI); 


of  red  or  white  mortar  stuck  on,  to  imitate  ashlar.  Such  work 
should  be  specified  to  be  laid  with  beds  and  joints  undressed,  pro- 
jections knocked  off  and  laid  at  random  and  interstices  filled  with 
spalls  and  mortar.  If  a  better  class  of  work  is  desired,  the  joints 
and  beds  should  be  specified  to  be  hammer-dressed. 

Fig.  94  shows  a  kind  of  rubble-work  sometimes  used  for  build- 
ings,  which  is  quite  effective  for  suburban  architecture.  It  should 
be  specified  to  have  hammer-dressed  joints,  not  exceeding  or 
94  of  an  inch,  with  no  spalls. on  the  face.  This  is  generally  expensive 
work. 

Fig.  95  shows  a  rubble  wall  with  brick  quoins  and  jambs. 
Occasionally  small  boulders  or  field-stone  are  used  for  the  walls 
of  rustic  buildings.    In  such  cases  the  walls  should  be  quite  thick, 


Fig.  93. — Rubble  Stonework,  Undressed,  Laid  at  Random. 

with  backings  of  split  stone,  to  hold  the  boulders ;  and  the  exact 
manner  in  which  the  walls  are  to  be  built  should  be  specified.  There 
are  several  kinds  of  rubble  used  in  engineering  work,  but  the  above 
are  about  the  only  styles  used  in  buildings. 

269.  ASHLAR. — The  outside  facing  of  a  wall,  when  of  cut- 
stone,  is  called  ashlar,  without  regard  to  the  way  in  which  the  stone 
is  finished.  Ashlar  is  generally  laid  either  in  continuous  courses, 
as  in  Figs.  96  and  97,  or  in  broken  courses,  as  in  Fig.  loi  ;  or  with- 
out any  continuous  horizontal  joints,  as  in  Figs.  98  and  99,  which 
represent  broken-ashlar. 

270.  COURSED-WORK. — Coursed-work  is  always  the  cheap- 
est when  stones  of  a  given  size  can  be  readily  quarried,  as  is  usually 
the  case  with  sandstones  and  limestones.    The  cheapest  ashlar  for 


CUT-STONEWORK, 


265 


most  stones  is  that  which  is  cut  into  12-inch  courses,  with  the  length 
of  the  stones  varyincr  from  18  to  24  inches.  When  they  are  cut  from 
30  inches  to  3  feet  in  length,  and  with  the  end  joints  plumb  over 
each  other,  as  in  Fig.  96,  the  cost  is  considerably  increased,  and  if 
this  kind  of  work  is  desired  it  should  be  particularly  specified. 

Fig.  96  is  regular-coursed-ashlar,  each  course  being  the  same 
height  with  plumb  bond.  When  the  courses  of  stone  are  of  differ- 
ent heights  it  is  called  irregular-coursed-ashlar. 

A  form  of  ashlar  now  much  used  is  that  shown  in  Fig.  97,  in 
which  wide  and  narrow  courses  alternate  with  each  other.  Six 
inches  and  14  inches  make  good  heights  for  the  courses. 

Fig.  102  shows  regular-coursed-ashlar,  with  rustic  quoins  and 
plinth,  which  is  much  used  in  Europe. 


Fig.    94. — Random-Rubble    Stonework   with   Hammer-  Fig.  95. — Dressed  Rubble  Stone- 

dressed  Joints  and  No  Si)alls  on  Face,  and  work    with     Brick  Quoins 

with  Quoins.  and    Brick  Jambs. 


271.  BROKEN-ASHLAR. — When  stones  of  uniform  size  can- 
not be  cheaply  quarried  the  stone  may  be  used  to  better  advantage 
in  broken-ashlar,  but  it  takes  longer  to  lay  it,  and,  as  a  rule,  broken- 
ashlar  costs  considerably  more  than  coursed-ashlar.  This  style  of 
work  is  generally  considered  the  most  pleasing,  and,  when  done 
w^ith  care,  makes  a  very  handsome  wall,  as  shown  by  the  half-tone 
illustration.  Fig.  lOO.  It  is  generally  used  for  rock-face  work 
only.  To  present  the  best  appearance  no  horizontal  joint  should  be 
more  than  4  feet  long,  and  several  sizes  of  stones  should  be  used. 
Broken-ashlar  can  be  more  quickly  laid,  and  at  le^s  expense,  if  the 
stones  are  cut  to  certain  heights  in  the  yard,  necessitating  the  cut- 
ting of  one  end  joint  only  at  the  building. 

The  wall  shown  in  Fig.  98  is  made  up  of  stones  cut  4,  6,  8,  10, 
12  and  14  inches  in  height,  wliile  in  Fig.  99  only  three  sizes  of  stones 


BUILDING    CONSTRUCTION.  (Ch.VI) 


266 


are  shown.  Fig.  98  shows  the  combination  generally  considered 
the  more  pleasing.  In  specifying  broken-ashlar  the  height  of  the 
stones  to  be  used  should  be  specified.    Broken-ashlar  is  sometimes 


96. — Coursed-aslilar    Istonework.     Regular  Pitimu 
Bond. 


arranged  in  courses  from  18  to  24  inches  high,  as  in  Fig.  loi,  when 
it  is  called  random-coursed-ashlar.    It  looks  very  well  in  piers. 

272.  QUOINS  AND  JAMBS.— The  stones  at  the  corners  of 
buildings  are  called  the  quoins,  and  these  are  often  emphasized,  as 


Fig.  97. — Coursed-ashlar  Stonework. 

irregular  Plumb  Bond. 


Regular- 


shown  in  Figs.  94  and  102.  They  should  always  be  equal  in  size  to 
the  largest  of  the  stones  used  in  the  wall.  The  stones  at  the  sides 
of  a  door  or  window  opening  are  called  jambs.    Fig.  103  represents 


CUT-STONEWORK. 


26j 


cut-stone  window  jambs  in  a  rubble  wall.  A  portion  of  the  jamb- 
stones  should  extend  through  the  wall  to  give  a  good  bond. 

In  rubble  walls  the  quoins  and  "jambs  are  often  built  of  brick,  as 
shown  in  Fig.  95. 


io 


Fig. 


-Broken-ashlar  Stonework  (Six  Sizes). 


All  ashlar  work  should  have  the  bed-joints  perfectly  straight  and 
horizontal,  and  the  vertical  joints  perfectly  plumb,  or  the  appearance 
will  be  greatly  marred. 

273.    TRIMMINGS. — This  term  is  generally  used  to  denote  all 


—  I      \  ^ 

Fig.  99. — Broken-ashlar  Stonework  (Three  Sizes). 


moldings,  caps,  sills  and  other  stonework,  except  ashlar.  The  trim- 
mings may  be  pitched  off  on  the  face,  but  all  washes,  soffits  and 
jambs  should  be  cut  or  rubbed. 


268  BUILDING    CONSTRUCTION.  (Ch.VI) 


Fig.  100. — Broken-ashlar  Stonework,  Rock-face. 


Fig.  loi. — Random-coursed-ashlar  Stonework. 


Fig.  102. — Regular-coursed-ashlar  Stonework,  Rustic  Fig.    103. — Cut-stone  Win- 

Ouoins  and  Plinth.  dow   Jamb,  Rubble 

Wall. 


SrOXE-CUTTING    AND  FINISHING. 


269 


2.    STONE-CUTTING  AND  FINISHING. 

274.  STONE-CUTTING  TOOLS.— In  order  that  the  architect 
may  specify  correctly  how  he  wishes  the  stone  in  his  buildings  fin- 
ished, it  is  necessary  for  him  to  be  familiar  with  the  tools  used  in 


Fig.   104. — Axe  or  Pean-  Fig.   105. — Tootli-axe. 


hammer. 

cutting  and  with  the  technical  names  given  to  different  kinds  of 
finish. 

There  are  several  kinds  of  hammers  used  by  masons  in  dressing 


Fig.   106. — Bush-hammer. 


rubble,  and  also  a  variety  of  tools  used  in  quarrying,  but  as  they  are 
not  used  in  working  the  finished  stone  they  will  not  be  described. 
The  Axe  or  Pean-hammer,  Fig.  104,  has  two  cutting-edges.  It 


2/0 


BUILD  IXG 


CONSTRUCTIOhL 


(Ch.  VI) 


is  used  for  making  drafts  or  margin-lines  around  the  edges  of  the 
stones  and  for  reducing  the  faces  to  a  level.  It  is  used  after  the 
point  on  granite  and  other  hard  stones. 


Fig.   107. — Crandall.  Fig.  108. — Patent-hammer. 


The  Tooth-axc,  Fig.  105,  has  its  cutting-edges  divided  into  teeth, 
the  number  of  which  varies  with  the  kind  of  work  required.  It  is 
used  for  reducing  the  face  of  sandstones  to  a  level,  ready  for  the 
crandall  or  tool.    It  is  not  used  on  granites  and  hard  stones. 

The  Biish-hainmer,  Fig.  106,  is  a  square  hammer,  with  its  ends 
(from  2  to  4  inches  square)  cut  into  a  number  of  pyramidal  points. 
It  is  used  for  finishing  the  surface  of  the  hardest  sandstones  anel 
limestones,  after  the  face  of  the  stone  has  been  brought  nearly  to 
the  plane  required. 


I  S  3        4  5  6  7  8 

Fig.   109. — Chisels. 


The  Crandall,  Fig.  107,  is  a  malleable  iron  bar  about  2  feet  long, 
slightly  flattened  at  one  end,  in  which  is  a  slot  y%  of  an  inch  wide 
and  3  inches  long.  Through  this  slot  are  passed  ten  double-headed 
points  of  ^-inch  square  steel,  about  9  inches  long,  which  are  held 
in  place  by  a  key.  Only  one  end  of  the  crandall  is  used,  and  as 
the  points  become  dull  they  can  be  taken  out  and  sharpened,  or  the 


STONE-CUTTING    AND    FINISHING.  271 


ends  can  be  reversed.  It  is  used  for  finishing  sandstones  after  the* 
surfaces  have  been  prepared  by  the  tooth-axe  or  chisel. 

The  Patcnt-hainuicr,  Fig.  108,  sometimes  called  the  bush-ham- 
mer, is  made  of  four,  six,  eight  or  ten  thin  blades  of  steel,  ground 
to  an  edge  and  bolted  together  so  as  to  form  a  single  piece.  It  is 
used  for  finishing  granite  and  hard  limestones,  the  fineness  of  the 
finish  being  regulated  by  the  number  of  blades  used. 

The  Point,  Fig.  109,  No.  4,  has  a  sharp  point,  and  is  used  in 
breaking  off  the  rough  surfaces  of  the  stones  and  reducing  them 
to  planes,  ready  for  the  axe,  hammer  or  tool.  It  is  also  used  to 
give  a  rough  finish  to  stones  for  broached  worl*  and  also  for  picked 
work.    No.  I,  Fig.  109,  represents  the  tooth-chisel,  used  only  on 


soft  stones ;  No.  2  a  drove,  about  2  or  3  inches  wide ;  Nos.  3,  7  and 
8  different  forms  of  chisels  used  on  soft  stones.  No.  5  is  a  tool, 
usually  from  33^  to  4^  inches  wide,  used  for  finishing  sandstones, 
and  No.  6  is  a  pitching  chisel,  used  as  in  Fig.  no. 

275.  DIFFERENT  KINDS  OF  VmiSH.— Rock-faced  or 
pitch-faced  work  is  shown  in  Fig.  no,  the  face  of  the  stone  being 
left  rough  as  it  comes  from  the. quarry,  with  the  joints  or  edges 
''pitched  off''  to  a  line  as  shown.  The  greatest  projection  of  the 
face  of  the  stone  beyond  the  plane  of  the  joints  should  be  specified. 
The  ashlar  shown  in  Fig.  100  is  ''rock-faced." 

Rock-faced  zvork  with  margin  or  draft-lines  is  shown  in  Fig. 
III.  The  margin  (often  called  draft-line)  is  cut  with  a  tool-chisel 
on  soft  stones  and  with  an  axe  on  granites.  Sometimes  only  the 
angle  of  the  quoins  has  a  draft-line,  as  in  Fig.  112,  when  it  is 
called  an  "angle-draft."  Rock-faced  ashlar  is  naturally  cheaper 
than  any  kind  of  dressed  ashlar,  particularly  in  granite. 


Fig.  1 10. — Rock-faced  or  Pitch-faced 
Stone-pitching  Chisel. 


Fig. 


g.  III.  —  Rock-faced  Stone 
with   Draft-line   or  Margin. 


272 


BUILDING  CONSTRUCTION. 


(Ch.  VI) 


*  Broached  Work. — The  surface  of  tlie  stone  is  dressed  ofif  to  a 
level  surface,  with  continuous  grooves  made  in  it  by  the  point.  Fig. 
113  shows  a  stone  with  margin  or  draft-lines  and  broached  center. 

Pointed  Work  (Figs.  114  and 
115). — When  it  is  desired  to  dress 
the  face  of  a  stone  so  that  it  will 
not  project  more  than  from  ^  to 
y2  an  inch,  and  when  a  smooth 
finish  is  not  required,  as  in  base- 
ment piers,  etc.,  the  rock-face  is 
taken  ofif  with  a  point  and  the  sur- 
face is  rough-pointed  or  fine- 
pointed,  according  as  the  point  is 
used  over  every  inch  or  half -inch 
of  the  stone.  The  point  is  used 
oftener  for  dressing  hard  stones 
than  soft  stones. 
Tooth-chiselled  Work.  —  The 
cheapest  method  of  dressing  soft  stones  is  the  one  in  which  the 
tooth-chisel  only  is  used.  .  This  gives  a  surface  very  much  like 
pointed  work,  but  usually  it  is  not  so  regular.    (See  Fig.  109,  i.) 

Tooled  work  is  done  with  a  flat  chisel  from  3^  to  43^  inches  wide 
(see  Fig.  109,  5),  and  the  lines  are  continued  clear  across  the  width 


Fig.   113. — Broached  Stone  with  Fig.     114. — Rough-pointed 

Tooled  Margin  or  Draft-line.  Stone   with  Margin. 


of  the  piece,  as  shown  m  Fig.  ii6.  Wh-en  well  done  it  makes  a  very 
pretty  finish  for  sandstones  and  limestones,  and  especially  for 
molded  work. 

Drove  work  is  much  like  tooled  work,  but  is  done  with  a  chisel 
about  inches  wide  and  in  rows  lengthwise  of  the  stone  face, 
as.  shown  in  Fig.  117.  Drove  work  does  not  take  quite  as  much 
time  as  tooled  work,  and  hence  is  cheaper;  but  it  does  not  look  so 
well.    (See  Fig.  109,  2.) 


Fig.    112. — Rock-faced    Stonework  with 
Angle-draft. 


STONE-CUTTING    AND  FINISHING, 


273 


Bush-hamincrcd  Work. — This  finish  is  made  by  pounding  the 
surface  of  the  stone  with  a  bush-hammer,  leaving  it  full  of  points, 
as  in  Fig.  120.  It  makes  a  very  attractive  finish  for  the  harder  kinds 
of  sandstones  and  limestones,  but  ought  not  to  be  used  on  soft 
stones. 

CrandaUcd  Work  (Fig.  118). — The  face  of  the  stone  is  dressed 
all  over  with  the  crandall,  which  gives  it  a  fine  pebbly  appearance 


Fig.  115. — -Fine-pointed 
Stone  with  Margin. 


Fig.  116. — Tooled  Stone. 


when  thoroughly  done.  It  makes  a  sparkling  surface  for  red  sand- 
stones, and  in  Massachusetts  is  used  more  than  any  other  finish  for 
sandstones.  The  crandall  is  not  used  on  granites  and  other  hard 
stones. 

Rubbed  Work. — One  of  the  handsomest  finishes  for  sandstones 
and  limestones  is  obtained  by  rubbing  their  surfaces  until  they  are 
perfectly  smooth,  either  by  hand,  using  a  smooth  piece  of  soft 


Fig. 


-nrove  Work  on 
Stone. 


Fig.   118. — Crandalled  Stone 
with  Margin. 


Stone  with  water  and  sand  •for  rubbing,  or  by  laying  the  stones  on 
a  revolving  bed  called  a  rubbing-bed.  When  the  stone  is  first  sawed 
into  slabs  the  rubbing  is  very  easily  and  cheaply  done,  so  that 
rubbed  sandstone  ashlar  is  often  as  cheap  as  rock- faced  work  in 
yards  where  steam  saws  are  used.  The  saws  leave  the  stone  com- 
paratively smooth  and  "suitable  for  the  top  of  copings  and  places 
which  are  not  in  view.  Granite  marbles  and  many  limestones,  when 
rubbed  long  enough,  take  a  high  polish. 


274  BUILDING    CONSTRUCTION.  (Ch.VI) 

Picked  Work. — In  this  work  the  face  of  the  stone  is  first  levelled 
off  with  the  point  and  then  picked  all  over.  Broken-ashlar  finished 
in  this  way  has  a  very  pretty  effect,  but  is  quite  expensive. 

Patent-hanimcrcd  or  Biish-hammcrcd  Work  (Fig.  119). — When 
it  is  desired  to  give  a  finished  surface  to  granites  and  hard  limestones 
they  are  first  dressed  to  a  rough  surface  with  the  point  and  then  to 
a  medium  surface  with  the  same  tool,  and  finally  finished  with  the 
patent-hammer.    The  fineness  of  the  finish  is  determined  by  the 


Fig.   119. — Patent-hammered  Fig.  120. — Bush-hammered 

Stone  with  Margin.  Stone  -with  Margin. 

number  of  blades  in  the  hammer,  and  the  work  is  said  to  be  "six- 
cut,"  ''eight-cut"  or  "ten-cut,"  as  six,  eight  or  ten  blades  are  used. 
Gcvernment  work  is  generally  ten-cut.  Eight-cut  is  generally  used 
for  average  work,  and  for  steps  and  doorsills  six-cut  is  suffi- 
ciently fine.  The  architect  should  always  specify  the  number  of 
blades  to  be  used  when  the  work  is  to  be  finished  with  a  patent- 
hammer.  The  same  finish  may  be  obtained  with  the  axe  or  pean- 
hammer,  but  it  requires  much  more  time. 


Fig.    121.  —  Vermiculpted   Work  Fig.  122. — Fish-scale  ^^'ork  with 

with  Chiselled  Margin.  Chiselled  Margin. 


Vermiculated  Work  (Fig.  121). — Stones  dressed  so  as  to  have 
the  appearance  of  having  been  worked  by  worms.  This  work  is 
generally  confined  to  quoins  and  base-courses. 

Rusticated  Work. — This  term  is  now  generally  used  to  denote 
.sunk  or  bevelled  joints,  as  in  Figs.  102  and  123,  although  it  originally 


CUT -STONE  TRIMMINGS. 


275 


referred  to  work  honeycombed  all  over  on  the  face  to  give  a  rough 
effect,  as  shown  in  Fig.  102. 

Fish  Scale  or  Hammered  Brass  Work  (Fig.  122). — Work  made 
to  imitate  hammered  brass,  and  done  with  a  tool  with  rounded 
corners. 

Vermiculated  and  fish-scale  work  are  seldom  seen  in  this  country. 

276.  LAYING  OUT  WORK.~If  the  cost  of  the  stonework 
must  be  considered,  the  architect  should  ascertain  from  some  reliable 
local  stone-dealer  the  most  economical  size  for  the  kind  of  stone  he 
intends  to  use,  and  lay  out  his  work  accordingly. 

3.    MISCELLANEOUS  CUT-STONE  TRIMMINGS. 

277. '  CUT-STONE  TRIMMINGS  IN  BRICK  BUILDINGS.— 
If  the  stonework  consists  merely  of  trimmings  for  a  brick  building, 
the  architect  or  his  draughtsman  must  first  ascertain  the  exact  meas- 
urement of  the  bricks  as  laid  in  the  wall,  and  the  stones  must  be 
figured  so  as  to  exactlv  fit  in  with  the  brickwork ;  otherwise  the 


Fig.    123. — Rusticated  Joints  in  Ashlar  Stonework. 


bricks  will  have  to  be  split  where  they  come  against  the  stones, 
thereby  greatly  marring  tlie  looks  of  the  building.  Bond-stones 
and  belt-courses  built  into  a  pier  must  conform  exactly  to  the  size 
of  the  pier.  As  it  is  seldom  that  the  bricks  from  any  two  yards  are 
of  exactly  the  same  size,  the  exact  size  of  the  bricks  that  are  to  be 
used  must  be  taken,  as  even  a  variation  of  j/^  of  an  inch  often  makes 
bad  work. 

278.  DRIPS. — Projecting  cornices,  belt-courses  and  other  trim- 
mings should  have  depth  enough  to  balance  on  the  wall,  and  all  pro- 


276  BUILDING    CONSTRUCTION.  (Ch.  VI) 


jecting  stones  should  have  a  drip  as  near  the  top  of  the  stone  as 
possible,  to  prevent  the  water  from  dripping  over  the  rest  of  the 
moldings  and  down  on  the  wall.  Thus  in  a  cornice  such  as  shown 
in  Fig.  124  the  stone  should  be  cut  at  a  sharp  angle  at  A,  so  that 
some  of  the  water  will  drop  ofif,  and  there  should  be  a  regular  drip 
at  B,  so  that  the  water  will  not  run  down  on  the  wall.  It  is  a  good 
idea  to  cut  a  drip  in  all  window  sills,  as  shown  in  Fig.  125.    In  the 


Fig.  124. — Stone  Cornice  witli  Drip  and  Wash. 


Fig.    125. — Stone  W  indow 
Sill   with   Drip  and 
Wash. 


summer  dust  always  lodges  on  sills  and  projecting  ledges,  and 
when  it  rains  the  water  washes  the  dust,  which  often  contains  cin- 
ders, over  the  face  of  the  stonework  and  down  on  the  wall,  causing 
both  to  become  streaked  and  unsightly. 

The  architect  will  find  that  if  he  is  careful  to  provide  drips  on  all 
moldings  and  sills  his  buildings  will  remain  bright  and  clean  for  a 


Fig.  126. — Top  of  Stone  Belt-course  Around  Pilaster. 

much  longer  time  than  would  otherwise  be  the  case.  Some  think 
it  is  even  better  to  slightly  change  the  profile  of  the  molding  if 
necessary,  in  order  to  provide  a  drip,  as  the  most  beautiful  mold- 
ing looks  unsightly  when  streaked  and  stained  with  dirty  water. 

279.  WASHES. — The  top  surfaces  of  all  cornices,  belt-courses, 
capitals,  etc.,  should  be  cut  so  as  to  pitch  outward  from  the  wall  line, 
as  shown  in  Fig.  124.  If  the  top  is  left  level,  the  rain  water  falling 
upon  it  will,  in  time,  disintegrate  the  mortar  in  the  joint  above  and 


CUT-STONE  TRIMMINGS. 


277 


finally  penetrate  into  the  wall.  Surfaces  bevelled  in  this  way  are 
called  washes. 

When  the  face  of  the  wall  is  broken  with  pilasters,  or  the  windows 


r  J 


Fig.  127. — Stone  Ashlar  Cut  to  Relieve  Lintel  or  Cap. 

are  recessed,  the  wash  on  the  belt-courses  should  be  cut  to  fit  the 
plan  of  the  wall  above,  as  shown  in  Fig.  126. 

280.  STONE  RELIEVING  AND  SUPPORTING  LINTELS. 
— A  stone  lintel  is  a  stone  which  covers  a  door  opening  or  window 
opening,  and  which,  therefore,  acts  as  a  beam. 
It  is  often  called  by  stonecutters  a  "cap." 
VVhen  it  is  necessary  to  use  a  rather  long  lintel 
in  a  stone  wall  the  ashlar  above  the  lintel  may 
be  arranged  so  as  to  relieve  the  lintel  of  some 
of  the  weight,  as  shown  in  Fig.  127.  If  the 
wall  above  the  lintel  is  of  brick  a  relieving- 
arch  may  be  turned  ;  but  this  generally  detracts 
from  the  appearance  of  the  building,-  and  the 
best  way  to  strengthen  the  lintel,  when  the 
length  does  not  exceed  6  feet,  is  to  let  it  rest 
on  a  steel  angle-bar  the  full  length  of  the  cap, 
as  shown  in  Fig.  128.  When  the  width  of  the 
opening  is  more  than  6  feet  the  lintel  should 
be  supported  by  steel  beams,  as  shown  in  Figs. 
129  and  130.  A  single  beam,  as  in  Fig.  129, 
may  be  used  where  only  the  weight  of  the  lintel  and  its  load  is  to  be 
supported,  and  two  or  more  beams  where  the  whole  thickness  of 
the  wall  and  also  the  floor  joists  must  be  supported. 

When  the  ^intel  is  the  full  thickness  of  the  wall,  and  steel  sup- 


Fig.    128. — Steel  Angle- 
bar,   Full   Length  of 
Stone  Cap.  Cap 
Less  Than  Six 
Feet  Long. 


278 


BUILDING    CONSTRUCTION.  (Ch.  VI) 


ports  are  undesirable,  the  strength  of  the  lintel  may  be  increased, 
when  it  is  a  stratified  stone,  by  cutting  it  so  that  the  layers  are  on 
edge,  like  a  number  of  planks  placed  side  by  .side.  The  Greeks  and 
Romans  often  cut  their  lintels  in  this  way,  and  apparently  for  this 
reason.  The  resistance  to  weathering,  however,  is  decreased  by  this 
method  of  cutting  and  setting. 

In  locating  windows  in  a  brick  or  stone  wall  the  designer  should 
be  careful  to  arrange  them  so  that  they  will  not  come  under  a  pier. 
This  is  not  apt  to  happen  in  the  front  of  a  building,  but  it  sometimes 
happens  in  the  side  or  rear  walls,  where  the  windows  are  placed  to 
suit  the  interior  arrangement  and  without  regard  to  the  external 
effect. 

If  a  door  or  window  must  be  placed  under  a  pier,  steel  beams 
should  be  used  to  support  the  wall  above  and  also  the  lintel.  Many 


Fig.     129. — One  1-Ream 
Supporting  Stone 
Lintel  and  Its 
Load. 


■■EM 


Fig.    130. — Two     LBeams     Supporting  Stone 
Lintel,  Wall  and  Joists;  Three-eighths-inch 
Steel  Plate  Rivetted  to  Beams. 


broken  lintels  are  evidences  of  a  too  frequent  neglect  of  this  pre- 
caution. 

Another  detail  that  should  be  carefully  considered  in  laying  out 
the  stonework  is  the  building  of  the  ends  of  caps  and  sills  into  the 
piers.  If  a  pier  extends  through  several  stories  all  the  joints  will 
be  slightly  compressed  and  the  masonry  will  settle  slightly ;  and  if 
the  ends  of  the  caps  and  sills  of  the  adjoining  windows  are  built 
solidly  into  the  piers  they  are  very  apt  to  be  broken  as  the  piers 
setde. 

It  is  better  to  keep  the  caps  and  sills  back  from  the  face  of  a 
pier,  and  either  to  build  pilasters  against  it  to  receive  the  caps  and 
sills,  as  shown  at  A,  Fig.  131,  or  to  build  the  ends  of  the  stones  into 


CUT-STOXE  TRIMMIXGS. 


279 


it  ill  such  a  way  that  they  can  give  a  Httlc.  When  these  stones  are 
back  from  the  face  of  a  pier  this  can  easily  be  done. 

Lintels  should  have  a  bearing  at  each  end  of  from  4  to  6  inches, 
•  according  to  the  width  of  the  opening.  It  is  better  not  to  build  tlie 
ends  into  the  wall  further  than  necessary  to  give  a  sufficient  bearing. 

281.  CO:\IPOSITE  STONE  LINTELS —Designs  sometimes 
require  a  stone  lintel  over  a  store  window  10  to  12  feet  wide.  To 
procure  such  a  lintel  in  one  piece  is,  in  many  places,  impracticable, 


1 

r    11  1 

-A 

1  J 

1  '  1  '  1  '  1  '  1 

'    1     1     '  1 

1  '  1  '  1  '  1  '  1  ' 

i  '  1  '  i  '  1  '  1  ' 

r:\  

-  '  1  l-i'i'i'  1  1  1  1 

1 '  t '".^ ' ; 

1  1 

-  '     1     '     '     '  1 

1  1 

1 

1 1 ;  1 ;  1 1 1 ; 

1 

1 

1 

1 

'  ,  1  , 

' — 1 — 

1 

1  ■  I  , 

1  ,  ,1,  1 

■  '  1  '  1  '  1 

1  1  '  1  1 

Fig.  131. — Pilasters  Against  Pier  to  Receive  Stone  Caps  and  Sills. 

and  it  is  therefore  necessary  to  build  up  the  lintel  in  pieces.  V/hen 
such  is  the  case  three  stones  at  least  should  be  used,  and  the  end 
joints  should  be  cut  as  shown  in  Fig.  132.  Stones  cut  in  this  way 
are  bound  together  better,  and  also  appear  to  be  self-supporting. 
A  greater-  number  of  stones,  usually  five  or  seven,  may  be  used  if 
preferred,  but  the  joints  should  be  cut  in  the  same  way.  Such  lintels 
should  always  be  supported  by  steel  beams,  as  shown  in  Figs.  129 
and  130. 


28o 


BUILDING    CONSTRUCTION.  (Ch.VI) 


282.  STONE  SILLS. — A  stone  ''sill"  is  a  piece  of  stone  placed 
at  the  bottom  of  a  window  opening  in  a  stone  or  brick  wall.  Door- 
steps or  thresholds  also  are  often  called  "sills." 

A  slip  sill  is  a  sill  that  is  just  the  width  of  the  opening,  and  is  not 
built  into  the  walls  at  the  jambs. 

A  lug  sill  is  a  sill  that  has  flat  ends,  built  into  the  walls,  as  shown 
in  Fig.  133. 

All  sills  should  be  cut  with  a  wash  of  at  least  from  j/^  an  inch  to  5 


V 

132. — Composite  Stone  Lintel.    Openings  to  or  12  Feet  Wide. 
Always  with  Steel  Supports. 

inches  in  depth,  and  if  the  ends  are  to  be  built  into  the  wall  they 
should  be  cut  as  shown  in  Fig.  133.  In  some  parts  of  the  country 
each  sill  is  cut  with  a  straight  bevelled  surface  the  full  length  of 
the  stone,  and  when  it  is  built  into  the  wall  the  bricks  are  cut  to  fit 
it.  This  is  not  a  good  method,  as  the  water  running  down  the  jamb 
and  striking  the  sill  is  apt  to  enter  the  joint 
between  the  bricks  and  stone,  and  the  slant- 
ing surface  offers  an  insecure  bearing  for 
the  bricks. 

Slip  sills  are  cheaper  than  lug  sills,  but 
they  do  not  look  so  well ;  and  there  is  also 
danger  of  the  mortar  in  the  end  joints  being 
washed  out  in  time. 

Slip  sills,  however,  are  not  likely  to  be 
broken  by  any  settlement  in  the  brickwork, 
and  for  this  reason  many  architects  prefer  to 
use  them  for  the  lower  openings  in  heavy  buildings  and  also  for 
very  wide  openings. 

Lug  sills  should  be  built  not  more  than  4  inches  into  the  jambs, 
and  should  be  bedded  only  at  the  ends  when  setting. 

283.  CUT-STONE  ARCHES.  NAMES  OF  VARIOUS 
PARTS. — Figure  134,  ''Cut-stone  Arch  and  Vault  with  Names  of 
the  Various  Parts  of  the  Arch,"  illustrates  the  different  construc- 
tional divisions  of  this  kind  of  masonry. 


Fig.      133. — Stone 
Sill  Showing 
Ends,   Wash  and 
.  Drip. 


Lug 


Flat 


CUT -ST  ONE  TRIMMINGS. 


In  stone-cutting"  the  following  terms  also  are  often  used  for  the 
different  parts  of  arches  and  vaults : 

The  SoMt. — The  concave  surface  of  the  arch. 
The  Back. — The  convex  surface  of  the  arch. 

The  Spandrel  fiUing. — The  filling,  in  the  triangular  spaces  above 
the  voussoirs  and  between  the  springers  and  the  crown. 

A  Ring-course. — A  course  of  stones  parallel  to  the  voussoirs. 

The  Arch-ring. — The  voussoirs,  taken  together. 

284.  STONE  ARCHES.  GENERAL  DETAILS.— Stone 
arches  are  very  frequently  used  in  both  stone  and  brick  buildings. 


CrouJrv. 

Keystone^ 

Fig.  134. — Cut-stone  Arch  and  Vault  with  Names  of  Various  Parts  of  the  Arch. 

They  may  be  built  in  a  great  variety  of  styles,  and  with  either  circu- 
lar, elliptical  or  pointed  soffits.  The  method  of  calculating  the  sta- 
bility of  a  stone  arch  is  the  same  as  for  a  brick  arch ;  but  since  a 
stone  arch  is  constructed  of  larger  pieces,  the  mortar  in  the  joints 
adds  very  little,  if  anything,  to  its  stability,  and  a  stone  arch  of  the 
same  size  as  a  brick  arch  is  rather  more  liable  to  settle  or  crack 
than  the  latter,  and  should  be  constructed  with  greater  care.  The 
method  of  calculating  the  stability  of  arches  is  given  in  Chapter  VIII 
of  the  ''Architect's  and  Builder's  Pocket-Book."  In  block  stone 
arches  each  block,  or  'Voussoir,"  should  always  be  cut  wedge-shape 
and  exactly  fitted  to  the  place  it  is  to  occupy  in  the  arch.  The  joints 
between  the  voussoirs  should  be  of  equal  width  the  entire  depth 


282 


BUILDING  CONSTRUCTION. 


(Ch.  VI) 


and  thickness  of  the  arch,  in  order  that  the  bearing  may  be  uni- 
form over  the  entire  surface.  The  thickness  of  the  joints  will  de- 
pend somewhat  upon  the  character  of  the  stonework.  In  finely 
dressed  work  j\  of  an  inch  is  the  usual  thickness,  while  in  rock- 
faced  work  they  are  seldom  made  less  than  }i  of  an  inch.  One- 


Fig.    135. — Common   Semi-circular   Stilted   Stone  Arch. 

fourth  of  an  inch,  however,  is  all  that  should  be  allowed  in  first-class 
work. 

The  joints  should  also  radiate  from  the  center  from  which  the 
intrados  is  struck,  or,  in  the  case  of  an  elliptical  arch,  they  should 
be  at  right-angles  to  a  tangent  drawn  to  the  intrados  at  that  point. 
(See  Fig.  140,  Article  290.) 

The  back  of  the  arch  may  be  either  concentric  with  the  intrados, 
or  the  ring  may  be  deeper  in  the  center  than  at  the  sides. 


Fig.  136.^ — Semi-circular    Stone    Arch.      Vous-  Fig.      137.    —  Stone 

soirs  Cut  to  Bond  witli  Coursed-ashlar.  Voussoirs  Bonding 

with  Coursed-ash- 
lar. 


The  most  common  stone  arch  is  that  shown  in  Fig.  135,  the  arch 
.ring  being  of  equal  depth  and  the  voussoirs  all  of  the  same  size, 
and  rock-faced  with  pitched  joints.  Occasionally  the  voussoirs  are 
cut  with  a  narrow  margin  draft,  as  shown  at  B.    When  the  spring- 


CUT-STONE  TRIMMINGS. 


283 


ing  line  of  an  arch  is  below  the  center,  as  shown  in  Fig.  135,  the  arch 
is  said  to  be  ''stilted,"  the  distance  6"  being  called  the  "stilt."  Stilted 
arches  are  very  common  in  Romanesque  architecture. 

A  semi-circular  arch  is  one  of  the  best  shapes  for  supporting  a 
wall.  It  must,  however,  have  sufficient  abutments,  and  the  depth  of 
the  arch-ring,  or  the  normal  distance  in  feet  from  the  intrados  to 
the  extrados  should  be  equal  to  at  least 


0.2  -f- 


V  radius  -f-  half  span 


Arches  used  in  connection  with  coursed-ashlar,  especially  in 
Renaissance  buildings,  often  have  the  voussoirs  cut  to  the  shapes 
shown  in  Figs.  136  and  137. 

Such  arches  are  of  course  more  expensive  than  arches  with  the 


Fig.  138. — Built-up  Stone  Arch. 

intrados  and  extrados  concentric,  as  there  is  more  waste  to  the  stone, 
and  more  patterns  are  required.  They  have  a  more  pleasing  appear- 
ance, however,  and  are  also  stronger.  Voussoirs  of  the  shape  shown 
in  Fig.  137  must  be  cut  with  extreme  accuracy. 

In  dividing  an  arch  into  voussoirs  it  should  be  remembered  that, 
as  a  rule,  narrow  voussoirs  are  more  economical  of  material,  but 
more  expensive  in  point  of  labor. 

In  most  arches  the  width  of  the  voussoirs  at  the  bottom  is  about 
three-eighths  of  the  width  of  the  ring,  although  it  may  vary  from 
one-fourth  to  one-half. 

Two  voussoirs  are  cut  very  often  from  one  stone,  with  a  false 
joint  cut  in  the  center.   This  is  done  generally  for  economy,  although 


284  BUILDING    CONSTRUCTION.  (Ch.  VI) 

in  some  cases  it  may  add  to  the  stability  of  the  arch.  The  arch  is 
generally  divided  into  an  uneven  number  of  voussoirs,  so  as  to  have 
a  keystone,  the  voussoirs  being-  laid  from  each  side  and  the  keystone 
exactly  fitted  after  the  other  stones  are  set.  There  appears  to  be 
no  necessity  of  having  a  keystone,  and  the  author  has  been  informed 
that  Sir  Gilbert  Scott  always  used  an  even  number  of  voussoirs, 
believing  that  thereby  there  is  less  danger  of  the  voussoirs  cracking. 

285.  LABEL-MOLDINGS  ON  STONE  ARCHES.— In 
nearly  all  styles  of  architecture  the  better  class  of  buildings  have  the 
arch-ring  molded.  In  Gothic  and  Romanesque  work  a  projecting 
molding  called  a  "label-mold"  is  generally  placed  at  the  back  of 
the  arch.  When  not  very  large  it  may  be  cut  on  the  voussoirs,  but 
usually  it  is  made  a  separate  course  of  stone,  as  shown  in  Fig.  138. 


--..^—^  Fig.  139. 

~  "  '      Spandrel   Supports.      I  ^ 

A.  One  .Springing  Stone  for  Two       B.  Lower  \'oussoir  of  Stone  Arch  Cut 
Arches.  Full  Width  of  Pier. 

When  this  is  the  case  the  depth  of  the  arch-ring  without  the  label- 
mold  should  be  sufficient  for  stability.  The  label-mold  may  be  cut 
into  pieces  of  the  same  length  as  the  voussoirs,  or  the  joints  may 
be  made  independent  of  those  in  the  arch. 

286.  BUILT-UP  STONE  ARCHES.— Large  arches,  especially 
those  which  show  on  both  sides  of  the  wall,  are  often,  for  the  sake 
of  economy,  built  of  several  courses  of  stone,  jointed  so  as  to  have 
the  appearance  of  solid  voussoirs.  Fig.  138  shows  the  manner  in 
which  many  of  the  large  arches  designed  by  the  late  H.  H.  Richard- 
son were  constructed.  Every  alternate  pair  of  voussoirs  should  be 
tied  together  by  galvanized-iron  clamps. 

287.  BACKING  OF  STONE  ARCHES.— The  arches  generally 
seen  in  the  fronts  of  buildings  are  usually  only  about  6  inches  thick, 
and  are  backed  with  brick  arches.  The  brick  arches  should  be  of 
the  same  shape  as  the  stone  arches,  and  the  bricks  should  be  laid 


CUT-STONE  TRIMMINGS. 


2Ss 


in  cement  mortar,  so  that  there  may  be  no  settlement  in  the  joints. 
The  backing  should  be  well  tied  to  the  stonework  by  galvanized-iron 
clamps, 

288.  RELIEVING-BEAAIS  OVER  STONE  ARCHES.— Very 
often  arches  are  used  for  effect  in  places  where  sufficient  abutments 
cannot  be  provided  to  resist  the  thrust.  In  such  cases  one  or  more 
steel  beams  should  be  placed  in  the  wall  just  above  the  arches, 
with  the  ends  resting  over  the  vertical  supports  and  an  empty  joint 
left  under  the  middle  part  of  the  beams.  The  wall  above  can  then 
be  built  on  these  beams,  leaving  the  arches  with  nothing  but  their 
own  weight  to  support.  The  additional  weight  which  the  beams 
carry  to  the  abutments  also  greatly  increases  the  latter's  resistance 
to  a  horizontal  thrust.  The  beams  should  be  provided  with  anchors 
at  their  ends,  with  long  vertical  rods  passing  through  them,  to  tie 
the  different  parts  of  the  wall  together. 

Wherever  segmental  arches  are  used  it  is  always  a  safe  precaution 
to  place  steel  rods  back  of  them  to  take  up  the  thrust,  especially 
while  the  mortar  in  the  abutments  is  green. 
♦  289.  SUPPORT  FOR  SPANDRELS  OF  STONE  ARCHES.— 
Wherever  arches  are  used  in  groups  care  must  be  exercised  in  lay- 
ing out  the  springing  stones  to  give  a  level  support  for  the  spandrels. 
Thus  where  two  arches  come  together,  as  at  A,  Fig.  139,  if  the  first 
voussoir  is  cut  in  the  shape  of  the  arch  on  the  back  a  small  wedge- 
shaped  piece  of  stone  will  be  required  to  fill  the  space  between  the 
first  pair  of  voussoirs.  The  weight  of  the  wall  above  coming  on 
this  wedge  might  be  sufficient  to  force  the  voussoirs  in,  seriously 
mar  the  appearance  of  the  arch  and  cause  cracks  in  the  ashlar  above. 
This  danger  may  be  overcome  by  cutting  the  lower  stone,  a,  a,  in  one 
piece  for  both  arches  and  extending  the  voussoir,  B,  to  a  vertical 
joint  over  the  middle  of  the  pier.  This  gives  a  level  bearing  for  the 
lower  stone  in  the  spandrel  and  effectually  prevents  any  pushing  in 
of  the  voussoirs. 

Another  case  very  similar  to  this  often  occurs  where  the  back  of 
an  arch  comes  almost  to  the  corner  of  the  wall  or  projection,  as 
shown  at  B.  If  the  distance  between  the  back  of  the  arch  and  the 
angle  of  the  wall  is  less  than  8  inches  the  lower  voussoir  should  be 
cut  the  full  width  of  the  pier,  as  shown  in  the  illustration. 

290.  ELLIPTICAL  STONE  ARCHES.— Arches  built  either  in 
the  form  of  an  ellipse  or  oval,  or  pointed  at  the  crown  and  elliptical 


286 


BUILDING    CONSTRUCTION.         (Ch.  VI) 


at  the  springing,  are  often  used  for  architectural  effect  in  buildings, 
although  very  seldom  in  engineering  works.  Such  arches  are  very 
liable  either  to  open  at  the  crown  and  "kick  up"  at  the  haunches, 
or  to  fail  by  the  middle  voussoirs  being  forced  down.  An  elliptical 
arch,  especially  if  very  flat,  is  undesirable  for  spans  of  over  8  feet, 
and  should  never  be  used  without  ample  abutments  unless  beams  are 
placed  above  the  arch  as  described  in  Article  288. 

The  joints  of  an  elliptical  arch  should  be  exactly  normal  (at  right 
angles)  to  the  curve  of  the  soffit.  If  the  line  of  the  soffit  is  not  a  true 
ellipse,  but  is  made  up  of  circular  arcs  of  different  radii,  the  joints 
in  each  portion  of  the  arch  should  radiate  from  the  corresponding 
center.  Fig.  140  shows  an  easy  method  for  laying  out  the  joints 
where  the  curve  of  the  soffit  is  a  true  ellipse.    Let  M^,  il/o,  M.^,  etc., 


Fig.  140. — ]\Iethod  of  Laying  Out  Joints  of  Elliptical  Stone  Arch. 

be  points  on  the  ellipse  from  which  it  is  desired  to  draw  the  joints. 
Draw  tangents  to  the  ellipse  at  the  points  A  and  B  intersecting  at 
C.  Draw  lines  AB  and  OC  Draw  lines  from  il/^,  M,,  M3,  etc., 
perpendicular  to  OA  and  intersecting  OC  at  L^,  L^,  L3,  etc.  From 
these  points  draw  lines  perpendicular  to  AB,  intersecting  OA  at 
A'-,,  N.,,  N.„  etc.  Lines  drawn  through  N^M^,  A',.M.>,  etc.,  will  then 
be  normal  to  the  curve  and  give  the  joints  desired. 

291.  GENERAL  CONSTRUCTION  OF  A  THREE-CEN- 
TERED ARCH. — When  the  rise  is  to  be  not  less  than  one-third  the 
span,  a  three-centered  arch  is  usually  considered  to  give  a  curve 
more  pleasing  to  the  eye  than  one  of  a  greater  number  of  centers. 

Fig.  141,  "Cut-stone  Elliptical  Three-centered  Arch,"  indicates 
the  general  method  of  drawing  a  three-centered  curve  for  an  arch, 
when  the  two  centers  of  the  shorter  radii  are  on  the  springing  line 
AB. 


CUT-STONE  TRIMMINGS. 


287 


On  tlie  span  AB  and  on  the  rise  HF  are  set  off  AD  and  FR  respec- 
tively, these  distances  being  equal  to  each  other,  and  less  than  the 
rise  HF.  DE  is  drawn,  and  is  bisecte(1  by  the  perpendicular  CG 
which  is  produced  to  intersect  FH  at  C.  Then  will  C  and  D  be  two 
of  the  required  centers,  the  third  center  being  found  on  HB  at  a 
distance  to  the  right  of  H  equal  to  HD. 

An  infinite  number  of  curves  may  thus  be  constructed  for  the  same 
span  and  rise. 

292.  CUT-STONE  FOUR-CENTERED  TUDOR  ARCH.— 
The  curve  for  this  arch  is  shown  in  Fig  142,  and  may  be  con- 
structed as  follows :  Divide  the  span  AD  into  four  equal  parts, 
AB,  BO,  OC  and  CD.    From  B  and  C  as  centers,  and  with  radii 


Fig.    142. — Cut-stone  Four-centered  Tudor 
Arch. 


equal  to  BC,  describe  arcs  intersecting  at  F.  Draw  BF  and  pro- 
duce it  to  meet  a  perpendicular  to  AD  drawn  through  C ;  and  draw 
CF  and  produce  it  to  meet  a  perpendicular  to  AD  drawn  through 
B.  With  5  as  a  center  and  with  a  radius  AB  describe  the  arc 
AK,  and  with  C  as  a  center  and  with  a  radius  DC  describe  the  arc 
DL.  Then  with  //  as  a  center  and  with  a  radius  HK  describe  the 
arc  KE,  and  with  G  as  a  center  and  with  a  radius  GL  describe  the 
arc  LE. 

293.  CUT-STONE  GOTHIC  OR  POINTED  ARCH.— Fig. 
143  illustrates  the  general  form  of  one  of  these  arches.  In  this  par- 
ticular example  the  lines  of  the  intrados  and  extrados  are  concentric, 
and  the  arch  is,  as  it  were,  circumscribed  or  built  around  an  equi- 
lateral triangle,  each  side  of  which  is  equal  in  length  to  the  span. 


288 


BUILDING  CONSTRUCTION. 


(Cii.  VI) 


In  this  illustration  BE  is  the  springing  line,  and  A  is  in  each  case 
the  center  from  which  the  curve  of  the  intrados  of  the  arch-ring-  is 
drawn,  AC  being  the  radius  and  ecjual  to  the  span. 

Pointed  arches  are  constructed  of  many  different  proportions,  bv 
taking  different  positions  for  these  centers,  and  different  lengths 
for  the  radii. 

294.  CUT-STONE  SEGAIENTAL  ARCH.— Fig.  144  illus- 
trates the  general  form  of  a  segmental  arch,  w^hich  frequently  re- 
places the  full-centered  or  semi-circular  arch  because  of  limited  space 
for  rise.  It  is  often  used  to  span  openings  over  doors  and  win- 
dows.   Its  construction  is  simple  and  is  shown  in  the  figure  with 


c 

Fig.  143. — Cut-stone  Gothic  or  Pointed  Fig.   144. — Cut-stone  Segmental  Arch. 

Arch. 


its  intrados  curve  described  with  C  as  a  center  and  with  CA  equal  to 
CB  equal  to  AB  the  span,  as  a  radius. 

295.  FLAT  STONE  ARCHES.— Shallow  flat  arches  of  stone, 
although  somewhat  pleasing  to  the  eye,  are  very  objectionable  con- 
structionally.  If  a  flat  arch  must  be  used,  to  be  self-supporting  it 
should  be  of  such  height  that  a  segmental  arch  of  proper  size  can 
be  drawn  on  its  face,  as  indicated  by  the  dotted  lines  in  Fig.  145. 
Even  then  it  is  desirable  to  drop  the  keystone  about  i  inch  below  the 
soffit  line,  so  as  to  wedge  the  voussoirs  tightly  together.  An  arch 
such  as  is  shown  in  Fig.  145  might  be  safely  used  for  a  span  of  5 
feet,  but  with  greater  caution  for  larger  spans.  The  strength  of  such 
an  arch  may  be  increased  by  making  joggled"  joints,  that  is,  by 
notching  one  stone  into  the  other,  as  shown  by  the  dotted  lines  at  a. 
Such  joints,  however,  are  quite  expensive. 

A  very  shallow  flat  arch,  such  as  is  shown  in  Fig.  146,  should  be 
•cut  out  of  one  piece  of  stone,  so  as  to  be  in  reality  a  lintel  with  false 


CUT-STONE  TRIMMINGS. 


289 


joints  cut  on  its  face.  The  ends  of  the  hntel  should  have  a  bearing 
on  the  wall  of  6  inches,  as  shown  by  the  dotted  lines,  the  face  being 
cut  away  for  about  2  inches  in  depth  and  veneered  with  brick.  If 
this  method  is  too  expensive  the  lintel  might  be  cut  in  three  pieces 
and  supported  by  a  heavy  angle-bar,  as  shown  in  Fig.  128. 

Very  long  lintels  are  often 
made  in  the  form  of  a  flat  arch 
(see  Article  281),  but  are,  or 
should  be,  always  supported  by 
steel  beams  or  bars. 

296.  FLAT  ARCH  VOUS- 
SOIRS  WITH  VERTICAL 
FACE  JOINTS.— Built-up  lin- 
tels and  flat  arches  of  stone 
are  sometimes  constructed  with 
voussoirs  which  are  cut  as  shown  in  Fig.  147.  Here  the  face  joints 
are  vertical  on  both  faces  of  the  arch,  but  the  arch  principle  is 
carried  out  by  forming  the  joint  vertically  on  only  about  4  inches 
of  the  voussoirs  back  from  each  face  of  the  arch-ring,  and  by 
cutting  the  joints  sloping  in  the  interior  as  shown. 

In  case  only  one  face  of  the  arch  ring  is  seen,  the  sloping  joints 
may  extend  back  through  the  voussoirs  to  the  back  face. 

297.  RUBBLE-STONE  ARCHES.— Arches  are  sometimes 
built  of  rubble  stones.  The  stones  should  be  long  and  narrow  and 
roughly  dressed  to  a  wedge  shape.   They  should  be  built  with  cement 


-Flat  Stone  Arch,  Joggled 
Joints. 


Fig.  146. — Shallow  Flat  Stone  Arch  in  One  Piece.    A  Lintel.    False  Joints. 

mortar,  as  they  depend  largely  upon  the  strength  of  the  mortar  for 
their  stability. 

298.  CENTERS  FOR  ARCHES.— Every  arch,  whether  of  stone 
or  brick,  should  be  built  on  a  wooden  center  made  to  exactly  fit  the 
curve  of  the  arch  and  carefully  set  in  place.  The  center  should  have 
ample  strength  to  support  the  weight  of  the  arch  and  much  of  the 
wall  above,  as  it  is  undesirable  to  put  any  weight  on  the  arch  until 


290 


BUILDING    CONSTRUCTION.         (Ch.  VI) 


the  mortar  in  the  joints  has  become  hard.  A  center  is  usually  made 
with  two  ribs  cut  out  of  plank  and  securely  spiked  together,  and  the 
bearing  surface  formed  of  cross  pieces  about  i  by  2  inches  in  size 
nailed  to  the  top  of  the  ribs,  as  shown  in  Fig.  148.  The  ribs  forming 
the  supports  for  the  cross  pieces  should  be  placed  under  each  edge 
of  the  arch,  and  if  the  depth  of  the  arch  exceeds  12  inches  three 


Fig.  147. — Stone  Voussoirs  for  Flat  Arch.    Vertical  Face 
Joints.     Sloping  Interior  Joints. 


ribs  should  be  used.  The  center  should  be  supported  on  wooden 
posts  resting  on  blocks  set  on  the  sill  or  some  sufficient  support  below. 
It  should  not  be  removed  until  the  mortar  in  the  arch  joints  has  had 
ample  time  to  set. 


Fig.  148. — Wooden  Center  for  Stone  Arch.    Usual  Construction. 


Centers  for  spans  of  considerable  width  are  framed  together  with 
heavier  timbers  and  in  a  variety  of  ways.  The  general  method  is 
shown  in  Fig.  149,  which  represents  a  center  for  a  lo-feet  span. 


CUT-STONE  TRIMMINGS. 


291 


outline  of  the  arch.  The  cross  pieces  are  then  nailed  to  the  top 
edge  of  the  planks,  as  in  Fig.  148.  Such  a  center  should  have  a 
support  under  the  middle  as  well  as  at  the  sides.  As  the  centers 
are  only  required  for  temporary  use,  architects  generally  allow  the 

carpenter  to  construct  them  as  he  deems 
best,  but  the  superintendent  should 
satisfy  himself  that  they  are  of  ample 
strength  and  well  supported  before  the 
masons  commence  building  the  arch. 

299.  COLUMNS. — Stone  columns  not 
exceeding  8  feet  in  height  usually  have 
the  shaft  cut  in  one  piece  and  the 
caps  and  bases  in  separate  pieces.  For 
columns  of  great  height  it  is  generally 
necessary  to  build  the  shaft  of  several 
pieces.  The  joints  between  the  cap  and 
base  and  the  shaft,  and  between  the  dif- 
ferent stones  of  the  shaft,  should  be  dressed  exactly  normal  to  the 
axis  of  the  column  and  to  a  true  plane,  so  that  the  pressure  will 
be  evenly  distributed  over  the  whole  area  of  the  joint.  Nothing  but 
cement  mortar  should  be  used  in  these  joints,  and  their  outer  parts 
for  ^  of  an  inch  back  from  the  face  should  be  left  empty  to 
prevent  the  outer  edges  of  the  stones  from  chipping  off. 


:.:\rr- 

Fig 


50. 


Common    Method  ( 
Building  Up  Parts  of  Stone 
Entablature. 


292 


BUILDING  CONSTRUCTION. 


(Ch.  VI) 


If  a  column  is  built  against  a  wall,  the  pieces  from  which  the 
cap  and  base  are  cut  should  either  extend  into  the  wall  or  be  secured 
to  it  by  galvanized-iron  clamps. 

300.  ENTABLx\TURES. — Stone  entablatures  spanning  porch 
openings,  etc.,  may  be  cut  from  one  piece  of  stone,  or,  if  of  con- 
siderable height,  may  be  built  up  with  several  horizontal  courses. 

Fig.  150  shows  a  common  method  of  building  up  the  lower  parts 
of  an  entablature,  the  corona  and  facia  being  in  still  another  course 
above  those  shown.    When  jointed  as  in  the  figure  the  bottom  joint 


should  not  be  filled  with  mortar  except  at  the  ends,  near  the  bearings. 

The  various  stones  composing  the  cornice,  frieze  and  architrave 
should  be  well  tied  together  with  iron  clamps,  especially  at  all  ex- 
ternal corners.  It  is  a  good  idea  also  to  tie  the  cornices  of  porches 
to  the  building  by  long  rods  built  inside  the  mason  work  to  prevent 
the  porches  from  "pulling  away"  from  the  walls. 

301.  STONE  COPINGS.— All  walls  not  covered  by  the  roof 
should  be  capped  with  wdde  stones  called  the  copings.  Horizontal 
copings  should  be  weathered  on  top  and  should  have  drips  at  the 
bottom  edges,  as  shown  in  drawing  Fig.  151.  The  width  of  the 
coping  should  be  about  3  inches  greater  than  that  of  the  wall. 

Gahlc  copings  do  not  require  weathering,  but  they  should  pro- 
ject about  inches  from  the  face  of  the.  wall,  and  should  have 
sharp  outer  edges,  so  that  the  water  will  not  run  in  against  the 
wall.  As  the  weight  of  a  sloping  coping  tends  to  cause  it  to  slide 
on  the  wall,  the  coping  should  be  well  anchored,  either  by  bonding 


Fig.  131. — Stone  Copings.     K.  Ciable  Coping  Kneeler. 
L.    Gable   Coping   Bond   Stone.  C.  Horizontal 
Coping  with  Drip   and  Weathering. 


CUT-STONE  TRIMMINGS. 


293 


some  of  the  stones  into  the  wall,  or  by  nsing-  long"  iron  anchors. 
The  bottom  stone,  sometimes  called  the  "kneeler,"  should  always 
be  well  bonded  into  the  wall  and  cut  with  a  horizontal  bed-joint, 
as  shown  at  K,  Fig.  151.  About  once  in  every  6  feet  in  height  a 
short  piece  of  coping  should  be  cut  so  as  to  bond  into  the  wall,  as 
at  L.  Gable  copings  sometimes  have  the  part  which  rests  on  the  wall 
cut  in  steps,  so  that  each  stone  has  a  horizontal  bearing.  This 
method,  however,  is  very  expensive,  unless  the  coping  is  cut  in  very 
short  pieces ;  and  this  is  objectionable  on  account  of  the  number  of 
joints  required. 

As  a  rule,  copings  should  be  designed  with  as  long  stones  as 
possible  to  decrease  the  number  . of  joints  and  the  admission  of 


302.  STONE  STEPS  AND  STAIRS.— These  should  always  be 
built  of  spme  hard  stone,  preferably  granite,  and  should  have  solid 
bearings.  Outside  steps  generally  rest  on  a  wall  at  each  end,  and  if 
more  than  6  feet  long  should  have  a  support  in  the  middle.  Each 
step  should  have  a  bearing  of  at  least  inches  on  the  back  part 
of  the  one  below.  Steps  to  outside  entrances  should  pitch  outward 
about  of  an  inch  Steps  are  much  easier  to  use  when  cut  with 
nosings ;  but  owing  to  the  increased  expense  they  are  used  only  in 
costly  buildings. 

Stone  stairs  may  be  built  with  one  end  only  supported.  In  Euro- 
pean buildings,  and  in  many  of  our  Government  buildings,  the  stairs 
are  constructed  as  shown  in  Fig.  152,  either  with  or  without  nosings. 
One  end  of  each  step  is  built  solidly  into  the  wall,  and  each  step  is 
supported  by  the  one  below,  owing  to  the  way  in  which  they  are  cut. 
The  bearing  of  one  step  on  another  should  be  not  less  than  that 
shown  in  the  figure.  The  bottom  step,  obviously,  must  be  well  sup- 
ported its  full  length,  as  it  has  to  sustain  nearly  the  full  weight  of  the 


Fig.   152. — Stone  Stairs  and  Landing. 


moisture.  Horizontal  coping  stones  are  often  clamped  together  at 
their  ends  to  prevent  their  getting  out  of  place  sideways. 


294 


BUILDING    CONSTRUCTION.         (Ch.  VI) 


stairs.  The  steps  are  usually  cut  with  a  triangular  cross-section  as 
shown,  as  this  shape  is  less  expensive  and  reduces  the  weight,  besides 
giving  a  pleasing  appearance  from  below. 

The  railing,  posts  and  balusters  are  generally  of  iron,  and  the 
latter  are  dowelled  into  the  ends  of  the  steps. 

The  laying  out  and  detailing  of  other  stone  trimmings  are  gov- 
erned by  the  principles  above  noted. 

303.  CIRCULAR  STAIRS  IN  STONE.— Circular  stairs  in 
stone  may  be  constructed  in  either  one  of  two  ways.  The  steps  may 
be  ''hanging  steps"  which  converge  toward  a  well-hole,  the  outer 
ends  of  the  steps  being  built  into  the  outside  walls,  or  they  may  be 


S£:cT/ON  THRouoH  a,  b.  3Ecr/oNAL  Plan 


Fig.  153. — Circular  Stone  Stairs. 

supported  at  both  ends,  by  the  outside  walls  and  by  a  central  newel. 

A  variation  of  the  latter,  and  a  very  common  construction,  espe- 
cially for  circular  staircases  of  small  diameter,  is  shown  in  Fig. 

153- 

Each  step  is  cut  out  in  the  form  indicated,  with  a  circular  portion 
on  the  inner  end  having  a  diameter  equal  to  that  of  the  intended 
newel. 

304.  BOND-STONES  AND  STONE  TEMPLATES.— The 
building  regulations  of  certain  cities  require  that  bond-stones  shall 
be  used  in  brick  piers  of  less  than  a  certain  size.  When  such  stones 
are  used  they  should  be  of  some  strong  variety,  and  should  be  cut 
the  full  size  of  the  pier.  It  is  also  very  important  that  the  outside 
and  inside  bricks  be  brought  exactly  to  the  same  level  to  receive  the 
stones;  for  if  the  latter  bear  on  the  outside  bricks  only,  the  weight 


TREATMENT— CUT-STONE    IN    WALL.  295 


will  cause  these  bricks  to  buckle  and  separate  from  the  pier,  whil^ 
if  the  weight  is  borne  by  the  middle  part,  the  pier  is  liable  to  crack 
through  at  that  point. 

Bond-stones  should  not  be  used  in  a  wall  in  the  manner  shown  in 
Fig.  154,  as  they  prevent  any  spreading  of  the  pressure,  and  keep 
concentrating  it  back  to  that  part  of  the  wall  which  is  immediately 
under  the  bond-stones,  as  shown  by  the  short  vertical  lines. 

Bearing-stones  used  under  the  ends  of  beams  or  girders,  to  dis- 
tribute the  weight  along  the  walls,  are  called  templates.  They  should 
always  be  very  hard,  strong  stones,  laminated  if  possible;  and  the 

thickness  of  each  stone  should  be  one-third 
of  its  narrowest  dimension,  unless  the  stone 
is  large,  but  in  no  case  less  than  4  inches. 
It  is  always  better  to  have  templates  too 
large  than  too  small. 

The  bearing  surface  of  the  templates 
should  be  such  that  the  pressure  which  it 
transmits  to  the  wall  below  shall  not  exceed 
120  pounds  per  square  inch,  or  about  8^^ 
tons  per  square  foot  for  common  brick- 
work; or  150  pounds,  or  about  10^  tons 
per  square  foot  for  common  rubble  with 
flat  beds. 

It  is  also  a  good  idea  to  place  a  flat  stone  above  the  end  of  a 
wooden  girder,  so  that  the  wall  will  not  rest  on  the  wood,  which  is 
quite  sure  to  shrink  and  possibly  affect  the  wall. 

4.    TREATMENT  OF  CUT-STONEWORK  IN  THE 

WALL. 


Fig.     154. — Bond-stones  and 
Template  in  I'rick  Wall. 
Incorrect  Method  of 
Construction. 


305.  LAYING  OUT  ASHLAR.— After  the  kind  and  size  of 
ashlar  to  be  used  has  been  determined  upon,  the  draughtsman  should 
show  each  piece  of  ashlar  on  the  elevation  drawings  if  coursed- 
ashlar  with  plumb  bond  is  to  be  used,  and  stones  of  particular 
lengths  desired.  If  there  are  piers  on  the  outside  of  the  building  a 
section  drawing  should  be  made  showing  how  the  stones  in  the  piers 
are  to  be  bonded  with  the  rest  of  the  wall. 

In  all  public  buildings  and  most  office  and  business  blocks  it  is 
generally  better  to  show  every  stone  on  the  plans  unless  broken-ashlar 
is  to  be  used,  in  which  case  the  labor  would  be  wasted.    As  a  rule. 


296 


BUILDING  CONSTRUCTION. 


(Ch.  VI) 


ii»  ordinary  stone  dwellings,  and  in  fact  in  most  stone  buildings, 
either  broken-ashlar  or  coursed-ashlar  of  irregular  lengths  is  used, 
and  in  either  case  it  is  not  necessary  to  indicate  the  ashlar  on  the 
elevation  drawings,  except  to  show  the  heights  of  the  courses,  if 
coursed-ashlar  is  used.  When  broken-ashlar  is  used  only  the  quoins 
and  jambs  and  a  small  piece  of  ashlar  indicating  the  kind  of  work 
desired  need  be  shown,  as  it  is  almost  impossible  for  masons  to 
careiully  follow  a  drawing  showing  broken-ashlar. 

306.  THICKNESS  OF  ASHLAR.— Broken-ashlar  and  coursed- 
ashlar  not  exceeding  12  inches  in  height  generally  varies  from  4 

to  8  inches  in  thickness,  and 
averages  6  inches.    The  dif- 
ferent courses  should  vary  in 
Ml  ^      thickness,  as  shown  in  Fig. 

In,.    i55.-Usual    Form    of   Anchor    for    Thin      159^    ^ud    it    is   better   tO  have 

Ashlar  facing.  ^^^^  coursc  4  iuchcs  and  the 

next  8  inches  than  to  have  all  6  inches  thick.  No  ashlar,  however, 
even  if  of  marble,  should  be  less  than  4  inches  in  thickness.  Ashlar 
laid  in  alternating  high  and  low  courses,  such  as  6  inches  and  14  or 
20  inches,  should  be  cut  so  that  the  low  courses  will  be  at  least  8 
inches  thick  and  the  high  courses  4  inches  thick ;  and  each  stone  in 
the  high  thin  courses,  when  18  inches  or  more  in  height,  should  have 
at  least  one  iron  anchor  extending  through  the  wall. 

Fig.  155  shows  the  form  of  anchor  generally  used.  The  high 
courses,  when  of  sandstone  or  limestone,  are  generally  sawed  to  a 
uniform  thickness. 

307.  JOINTS  IN  CUT-STONEWORK. 


-It  is  important  that 


Fig. 


56. — Bed-joint  in  .Stonework 
Worked  Hollow. 


Fig.  157. — Back  of  Bed-joint 
in    Stonework    Slack  or 
Hollow. 


the  exposed  surfaces  of  each  stone  should  be  ''out  of  winde" ;  that 
is,  true  planes  and  square  to  the  bed- joints  and  end  joints. 

The  bed-joints  should  be  full  and  square  to  the  face  and  n6t 
worked  hollow,  as  in  Fig.  156,  as  with  hollow  joints  the  least  settle- 


TREATMENT— CUT-STONE    IN    WALL.  297 


» 


298 


BUILDING    CONSTRUCTION,         (Ch.  VI) 


ment  in  the  mortar  will  throw  the  whole  pressure  onto  the  edge  of 
the  stone  as  shown  at  C,  and  cause  "spalls"  or  small  pieces  to 
splinter  off,  ruining  the  appearance  of  the  building,  and  suggesting 
unsafe  construction.  Stone-cutters  are  very  apt  to  work  the  joints 
hollow  and  the  back  of  the  joints  slack,  as  in  Fig.  157,  as  such  joints 
require  much  less  labor  than  evenly  dressed  joints;  and,  unless  care- 
fully looked  after,  they  will  cut  the  stones  slack  in  nine  cases  out  of 
ten.  If  the  back  of  a  joint  is  left  slack  and  underpinned,  as  in  Fig. 
157,  the  stone  is  then  supported  at  the  front  and  back  only,  and 
is  liable  to  break  in  the  middle,  as  shown.  Of  course,  in  a  wall 
not  exceeding  20  feet  in  height,  the  danger  arising  from  imperfect 
joints  is  not  as  great  as  in  a  wall  of  six  or  more  stories.  The 
higher  the  wall  the  more  carefully  should  the  joints  be  cut.  It  is 
also  desirable  that  the  joints  should  not  be  convex. 

For  very  heavy  masonry,  as  in  the  basement  or  first  story  of  tall 
buildings,  it  is  desirable  to  use  rusticated  joints  (see  Fig.  123),  as 
with  such  joints  the  face  is  less  apt  to  spall. 

The  thickness  of  ashlar  joints  varies  from  to  ^  of  an  inch.  A 
j4-inch  joint,  when  pointed,  makes  very  good-looking  work.  A 
J^-inch  joint  is  too  wide  for  anything  but  rock-faced  ashlar,  and 
nothing  over  a  i^-i^^ch  joint  should  be  used  for  heavy  work. 

308.  JOINTS.  GENERAL  PRINCIPLES.  JOINTS  IN 
TRACERY. — The  following  general  principles  should  be  observed 
in  arranging  the  joints  of  masonry  and  cut-stonework: 

(1)  All  bed- joints  should  be  arranged  at  right-angles  to  the  pres- 

sure coming  upon  them. 

(2)  All  joints  should  be  arranged  in  such  manner  that  all  members, 

such  as  sills,  shall  be  free  from  any  cross  or  flexural  stress. 

(3)  All  joints  should  be  arranged  in  such  manner  that  there  are 

no  acute  angles  on  either  one  of  the  pieces  of  stone  coming 
together. 

Principle  (i)  applies  to  all  kinds  of  masonry,  and  takes  account 
of  the  tendency  of  one  stone  to  slide  upon  the  other. 

Principle  (2)  applies  chiefly  to  stone  window  and  door  sills.  In 
stonework,  where  the  sills  must  be  set  as  the  work  proceeds,  their 
cracking  or  breaking  may  be  prevented  by  making  a  vertical  joinl 
in  the  line  of  the  face  of  the  reveal,  as  shown  in  the  elevation  of 
the  Gothic  window  in  Fig.  158.  When  heavy  stone  mullions  trans- 
mit considerable  Weight  to  the  sills,  the  same  precautions  must  be 
taken  with  the  latter;  while  if  the  mullions  are  light,  and  cause  no 


TREATMENT— CUT-STONE    IN    WALL.  299 


\ 

material  pressure,  continuous  sills  may  be  employed,  and  no  joint 
is  necessary  under  the  mullions.  It  is  better,  in  all  cases,  to  build 
the  stone  tracery  work  in  position,  especially  if  very  light,  after  the 
building  is  erected  and  all  settlement  has  taken  place.  This  prevents 
any  weights  being  transmitted  down  through  mullions  and  other 
portions  of  the  light  tracery. 

Principle  (3)  applies  especially  to  the  tracery  joints,  and  in  gen- 
eral to  exposed  joints  in  any  other  work.  Acute  angles  in  cut-stone 
weather  badly,  and  in  stone  tracery  in  which  several  members  inter- 
sect, the  stones  must  be  cut 
so  as  to  contain  the  entire 
intersection  and  also  a  short 
length  of  each  intersecting 
member,  as  shown  in  Fig. 
158.  The  joints  in  the  dif- 
ferent members  abutting 
should  always  be  cut  at 
right-angles  to  their  direc- 
tions. By  this  means  acute 
angles  are  prevented,  as  they 
would  not  be  in  case  the 
joints  were  made  along  the 
line  of  either  section  of  the 
moldings,  and  a  much  bet- 
ter finish  is  insured. 

Joints  should  never  be 
made  in  cut-stonework,  in 
tracery^ 
in  other 
miter  line. 

moldings  cannot  be  cut  or 
carved  when  mortar  joints  are  made  along  these  lines  of  intersection. 

309.  BACKING  OF  CUT-STONEWORK.— Both  stone  and 
brick  are  used  for  the  backing  of  ashlar.  Brick  is  used  more  largely 
than  stone  for  this  purpose,  because  in  most  cases  it  is  the  cheaper, 
and  because  in  dry  climates  plaster  can  be  applied  to  it  directly, 
whereas,  stone  backing  generally  has  to  be  plugged  and  stripped  for 
lathing.  If  brick  is  used  for  backing,  the  joints  should  be  made  as 
thin  as  possible,  and  it  is  desirable  to  use  some  cement  in  the  mortar 
to  prevent  shrinkage  in  them.   The  backing,  if  of  brick,  should  never 


I— 


Fig.  159.^ — Bonding  and  Backing  of  Stonework. 
A.   Brick   Backing.     B.    Stone  -Backing. 

Neat  and  lasting  intersections  of 


moldings 


at  anv 


300 


BUILDING    CONSTRUCTION.         (Ch.  VI) 


be  less  than  8  inches  in  thickness.  If  a  hard  laminated  stone,  with 
perfectly  flat  and  parallel  beds  can  be  obtained  for  backing,  a  stronger 
construction  will  result  than  if  bricjc  is  used;  but  irregular  rubble 
blocks  are  not  suitable  for  any  walls  but  dwelling-house  walls,  unless 
such  walls  are  made  one-fourth  thicker  than  they  would  be  with 
brick  backing.  The  backing,  whether  of  brick  or  stone,  should  be 
carried  up  at  the  same  time  the  ashlar  is  laid,  and,  if  of  stone,  it 
should  be  built  in  courses  of  the  same  height  as  the  ashlar  courses, 
as  shown  in  B,  Fig.  159. 

31a  BONDING  OF  CUT-STONEWORK.— Ashlar  not  ex- 
ceeding 12  inches  in  height  is  usually  sufficiently  bonded  to  the 
backing  by  making  the  stones  of  different  thickness,  as  in  Fig. 
159,  and  by  using  one  through  stone  to  every  10  square  feet  of  wall. 

Where  the  ashlar  is  only  from  2  to  4  inches  thick,  as  is  generally 
the  case  with  marble,  and  often  the  case  with  sandstones,  each  piece 
should  be  tied  to  the  backing  by  an  iron  clamp,  about  %  of  an 
inch  thick  and  i  or  1^4  inches  wide,  with  the  ends  turned  at  right- 
angles,  as  shown  in  Fig.  155.  The  anchors  should  be  made  of 
just  the  right  length  for  the  longer  end  to  turn  up  close  against  the 
inside  of  the  wall.  Every  stone  should  have  one  clamp,  and  if  a 
stone  is  over  3  feet  long  two  clamps  should  be  used  for  it.  There 
should  be  belt-courses,  also,  about  every  6  feet,  extending  8  inches 
or  more  into  the  walls,  to  add  support  to  the  ashlar. 

The  effective  thickness  of  a  wall  faced  with  thin  ashlar  is  the 
thickness  of  the  backing  only.  When  iron  clamps  are  used  for 
tying  the  ashlar  they  should  be  either  galvanized  or  dipped  into  hot 
tar  to  prevent  their  destruction  by  rust. 

311.  SETTING  CUT-STONEWORK.— All  stones  should  be 
set  in  a  full  bed  of  mortar,  and  any  stone  too  large  to  be  easily  lifted 
by  one  man  should  be  set  with  a  derrick. 

In  some  localities  slips  of  wood  of  the  thickness  desired  for  the 
joints  are  prepared  and  laid  on  the  top  of  the  stone  below ;  so  that 
when  a  stone  of  a  course  above  is  set  the  mortar  squeezes  out  until 
the  stone  rests  on  these  slips.  After  the  mortar  has  set  or  hardened 
the  slips  are  withdrawn.  The  bed  of  mortar  should  always  be  kept 
back  an  inch  or  more  from  the  edge  of  the  stone.  This  will  prevent 
the  stone  from  bearing  on  its  outer  edge,  and  save  raking  out  the 
mortar  preparatory  to  pointing.  In  damp  places  stonework  should 
be  set  in  cement,  or  in  lime-and-cement  mortar;  in  dry  places  it 
may  be  set  in  lime  mortar. 


TREATMENT— CUT-STONE    IN  WALL. 


Most  granular  limestones  and  marbles,  and  some  sandstones,  are 
stained  by  either  Portland  or  natural  cement,  and  when  using  any 
of  these  stones  for  the  first  time  the  architect  should  ascertain  their 
liability  to  be  stained.  The  mortar  for  bedding  the  stone  can  always 
be  kept  from  its  face  by  exercising  a  little  care,  and  the  joints  can 
be  afterward  pointed  w^ith  some  material  that  does  not  stain.  Stone- 
masons are  often  very  careless  in  setting  stonework,  and  do  not 
bed  the  stones  evenly,  so  that  when  a  considerable  weight  comes 
upon  them  they  crack. 

Marble  and  limestone  are  sometimes  set  in  a  cement  made  of  lime, 
plaster  of  Paris  and  marble  dust,  and  called  Lafarge  cement.  When 
such  cement  is  used  for  setting  the  cut-stonework,  and  other  cements 
for  the  backing,  the  back  of  the  cut-stone  should  be  plastered  with 
the  former  cement.    Window  and  door  sills  should  be  bedded  at 


1 


Fig.   160. — Jointer  for  Stonework  Joint.  "V -.v ' r' : ■  ^^^^ 

their  ends  only  with  no  mortar  under 
the  middle  part,  as  otherwise  any  set- 
tlement of  the  walls  will  break  them. 

312.  PROTECTING  CUT- 
STONEWORK.— The  carpenter's 
specifications  should  contain  a  clause 
providing  for  the  boxing  of  all  mold- 
ings, sills  and  ornamental  work  with 
rough  pine  to  prevent  the  stone  from 
being  damaged  during  the  construction  of  the  building.  Hemlock 
stains  the  stonework,  and  should  therefore  never  be"  used  for  this 
purpose. 

313.  POINTING  CUT-STONEWORK.— As  the  mortar  in  the 
exposed  edges  of  the  joints  is  very  apt  to  be  dislodged  by  the 
expansion  and  contraction  of  the  masonry  and  the  effects  of  the 
weather,  it  is  customary,  after  the  masonry  is  laid,  to  refill  the 


161. — Pointed  Joints 
Stonework. 


302 


BUILDIXG    COXSTRUCTIOK         (Ch.  VI) 


joints  to  a  depth  of  half  an  inch  or  more  with  mortar  prepared  espe- 
cially for  this  pnrpose.    This  operation  is  called  ''pointing/' 

Pointing  is  generally  done  as  soon  as  the  outside  of  the  building 
is  completed,  unless  it  should  be  too  late  in  the  season,  when  it  should 
be  delayed  until  spring.  Under  no  circumstances  should  it  be  done 
in  freezing  weather,  and  it  is  better  to  postpone  it  in  extremely  hot 
weather,  as  the  mortar  dries  too  quickly. 

Portland  cement  mixed  with  not  more  than  an  equal  volume  of 
fine  sand  and  such  coloring  matter  as  may  be  required,  with  just 
enough  water  to  give  the  compound  a  mealy  consistency,  makes  the 
most  durable  mortar  for  pointing.  If  the  stone  employed  is  stained 
by  a  cement,  either  Lafarge  cement  should  be  used,  or  else  a  putty 
made  of  lime,  plaster  of  Paris  and  white  lead. 

Before  doing  the  pointing  the  joints  should  be  raked  out  to  a 
depth  of  about  an  inch,  brushed  clean  and  well  moistened. 

The  mortar  is  applied  with  a  small  trowel  made  for  this  purpose 
and  is  then  squeezed  in  and  rubbed  smooth  with  a  t6ol  called  a 
"jointer"  (Fig.  i6o).  Jointers  are  made  with  both  hollow  and  con- 
cave edges,  so  as  to  give  a  raised  or  concave  joint,  as  shown  in 
Fig.  i6i.  The  concave  joint  is  the  most  durable,  although  the 
raised  joint  makes  perhaps  the  handsomest  work. 

314.  CLEANING  DOWN  CUT-STONEWORK.— This  con- 
sists in  washing  and  scrubbing  the  stonework  with  muriatic  acid 
and  water.  Wire  brushes  are  generally  used  for  marble  work  and 
sometimes  for  sandstone,  but  stiff  bristle  brushes  usually  answer 
the  purpose  just  as  well.  The  stones  should  be  scrubbed  until  all 
mortar  stains  and  dirt  are  entirely  removed.  The  cleaning  down  is 
done  in  connection  with  the  pointing. 

For  cleaning  an  old  front,  the  sand-blast,  using  either  steam  or 
compressed  air,  does  the  work  most  effectively,  as  it  removes  from 
1-64  to  1-32  of  an  inch  from  the  surface  of  the  stone,  making  it 
look  like  new.    Even  carving  can  be  successfully  treated  in  this  way. 

315.  SLIP' JOINTS  IN  WALLS.— Where  two  walls  differing 
considerably  in  height  come  together,  as,  for  instance,  where  the 
front  or  side  wall  of  a  church  joins  its  tower,  these  two  walls  should 
not  be  bonded  together,  but  the  low  wall  should  be  ''housed"  into 
the  other,  so  as  to  form  a  continuous  vertical  joint  from  bottom  to 
top,  as  shown  in  Fig.  162. 


STRENGTH    OF  CUT-STOXEWORK. 


303 


Such  a  joint  is  called  a  "slip  joint."  All  masonwork  built  with 
lime  mortar  will  settle  somewhat,  owing  to  the  slight  compression 
in  the  joints,  and  this  settlement  is  sometimes  sufficient  to  cause  a 
crack  where  a  high  and  low  wall  are  bonded  together.  In  such 
cases  there  is  a  chance  also  for  uneven  settlement  in  the  foundations, 
even  when  carefully  proportioned.  With  a  slip  joint  a  moderate 
settlement  may  take  place  without  showing  on  the  outside. 


5.    STRENGTH  OF  CUT-STONEWORK. 

316.    STRENGTH  OF  STONE  PIERS,  COLUMNS  AND 
LINTELS. — Practically  the  only  cases  in  which  the  strength  of 
stonework  need  be  considered  by  the  architect, 
other  than  those  having  to  do  with  the  proper 


type  of  construction,  are  those  involving:  a,  the 

strength  of  columns ; 


There  is  a  great 


Fig.  162.    Slip  Joint  in 
Stone  Walls. 


Strength  of  piers ;  h,  the 
c,  the  strength  of  lintels. 

a.  Strength  of  Stone  Piers 
variation  in  the  strength  of  stone,  even  when 
taken  from  the  same  quarry.  The  strength  of 
walls  and  piers  is  also  affected  by  the  kind  and 
quality  of  the  mortar  used,  by  the  way  the  work  is  built  and  bonded, 
and  it  also  depends  upon  whether  the  stone  is  laid  dry  or  wet. 
The  values  which  are  usually  given,  therefore,  for  strength  are 
values  which  will  be  safe  for  the  different  kinds  of  masonry  built 
in  the  usual  manner. 

The  larger  cities  have  building  laws  which  specify  the  greatest 
loads  allowed  per  square  foot  on  stone  piers  and  other  kinds  of 
masonry. 

A  factor  of  safety  of  at  least  10  should  be  allowed  for  stone 
piers,  when  the  safe  resistance  to  crushing  is  estimated  from  tests 
on  the  ultimate  strength  of  work  of  the  same  character. 

Some  building  ordinances  fix  the  maximum  stress  for  dimension- 
stone  piers  at  one-thirtieth  of  the  ultimate  strength  of  the  stone 
when  the  beds  are  dressed  to  a  uniform  bearing  over  their  entire 
surface,  and  at  one-fiftieth  of  the  ultimate  strength  when  the  beds 
are  not  dressed.  They  also  require  all  stones  to  be  bedded  in  Port- 
land cement  mortar  when  the  compressive  stress  exceeds  one- 
seventieth  of  the  ultimate  strength. 


304 


BUILDING    CONSTRUCTION.  (Ch.  VI) 


The  following  table  gives  the  safe  working  loads  for  stone  walls 
or  piers : 

TABLE  XXIV. 
Safe  Working  Loads  for  Stone  Walls  or  Piers. 

Rubble  walls,  irregular  stones  3     tons  per  square  foot. 

Rubble  walls,  coursed,  soft  stone  2]/2  tons  per  square  foot. 

Rubble  walls,  coursed,  hard  stone.  5  to  16  tons  per  square  foot. 

Dimension  stone,  squared,  in  cement : 

Sandstone  and  limestone  '..lo  to  20  tons  per  square  foot. 

Granite   20  to  40  tons  per  square  foot. 

Dressed  stone,  with  ^-inch  dressed  joints  in  cement: 

Granite   60  tons  per  square  foot. 

Marble  or  limestone,  best  40  tons  per  square  foot. 

Sandstone   30  tons  per  square  foot. 

The  height  of  these  piers  should  not  exceed  eight  times  the  least  di- 
mension in  plan. 

Ashlar  should  be  at  least  as  thick  as  it  is  high  and  it  should  be  well  bonded. 
When  piers  are  constrttcted  of  strong  stone  in  courses,  one  stone 
to  each  course,  and  all  bedded  even  and  true,  they  will  support  very 
heavy  loads.  When  the  height  of  such  pier  is  greater  than  eight 
times  the  least  dimension,  there  should  be  a  reduction  of  the  safe 
load,  and  in  any  case  the  height  should  not  exceed  ten  times  the 
least  dimension. 

The  stones  should  be  laid  in  i  to  2  Portland  cement  mortar, 
wdiich  should  be  kept  back  i  inch  from  the  faces  of  the  pier,  and 
the  thickness  of  the  joints  should  not  exceed  ^  of  an  inch.* 

b.  Strength  of  Stone  Columns. — A  stone  column,  free  from 
defects,  carefully  bedded  and  not  exceeding  ten  diameters  in  height, 
should  safel\  carry  a  load  equal  to  one-fifteenth  of  the  breaking 
load  of  stone  of  the  same  kind  and  quality.  Any  column  loaded 
with  over  fifteen  tons  to  the  square  foot  should  be  bedded  in  Port- 
land cement  mortar,  of  not  more  than  i  to  i  proportions,  and  the 
mortar  should  be  kept  back  i  inch  from  the  face  of  the  column 
until  after  the  work  is  completed,  when  the  joints  may  be  pointed 
as  in  ashlar.  As  it  is  difficult  to  make  a  mortar  joint  which  will 
stand  more  than  forty  tons  to  the  square  foot,  that  pressure  should 
be  the  limit  of  load  for  a  stone  column,  no  matter  how  strong  the 
stone  is,  imless  extra  precautions  are  taken  with  such  joints.  The 
following  values  may  be  used  for  the  safe  loads  of  columns  built 

*  For  additional  data,  records  of  tests,  etc.,  on  "The  Working  Strength  of  Masonry," 
"Stone  Piers,"  "Crushins^  Resistances  of  \'^arious  Building  Stones,"  etc.,  see  Chapter  V 
of  the  "Architect's  and  Builder's  Pocket-Book,"  by  F.  E.  Kidder. 


STRENGTH    OF  CUT-STONEWORK. 


305 


of  the  different  stones  specified,  the  shaft  of  each  cokimn  being  in 
one  piece : 

Columns.    One  Piece. 


Longmeadow  (Mass.)  red  sandstone,  best.  ...  35  tons  per  square 

foot. 

 40 

'i 

Manitou  (Colo.)  red  sandstone,  best.  . 

.  .25  to  30  " 

  25 

i  < 

  35  " 

<< 

.  .25  to  35 

<( 

......  40 

(( 

  40  " 

<l 

.  .30  to  35 

<c 

 .  .  40 

<( 

If  a  cohnim  is  built  up  of  several  pieces  the  joints  should  not 
exceed  i^ch  in  thickness,  and  the  bed  surfaces  should  be 

perfectly  true  and  square  to  the  axis  of  the  column. 

c.  Strength  of  Stone  Lintels:^' — A  lintel  is  nothing  more  than 
of  stone  beam,  and  the  same  formulas  apply  to  stone  and  to  wood, 
with  the  exception  of  the  quantity  representing  the  strength  or 
''modulus  of  rupture"  of  the  material.  The  following  formulas  give 
the  strength  of  lintels  under  symmetrically  distributed  and  centrally 
concentrated  loads,  the  only  cases  likely  to  occur  in  practice : 

2  X  breadth  X  square  of  depth 

Distributed  breaking  load  =   -. —  X  C. 

span  m  feet 

Concentrated  center  breaking  load=one-half  the  distributed  load. 

The  breadth  and  depth  should  be  taken  in  inches  and  the  break- 
ing load  in  pounds.  C  is  one-eighteenth  of  the  average  modulus  of 
rupture,  and  may  be  taken  as  follows : 

Granite,  100;  marble,  120;  limestone,  83;  sandstone,  70;  slate, 
300;  bluestone  flagging,  150. 

These  formulas  give  the  breaking  strength  of  the  lintel.  If  the 
load  on  the  lintel  consists  of  masonry  only,  and  is  not  subject  to 
shocks  or  impacts  of  any  kind,  the  safe  load  may  be  taken  at  one- 
sixth  of  the  breaking  load.  If  there  are  any  unfavorable  circum- 
stances the  safe  load  should  not  exceed  one-tenth  of  the  breaking 
load. 

Nearly  all  laminated  stones  are  stronger,  as  beams,  when  set  on 

*  For  a  discussion  of  the  "General  Principles  of  the  Strength  of  Beams,"  "Modulus 

of  Rupture"  or  "Flexural  Fiber  Strength,"  "Formulas  for  the  Strength  of  Beams,"  "Co- 
efficient«  for  Beams,"  etc.,  see  Chapters  XV  and  X\'I  of  the  "Architect's  and  Builder's 
Pocket-Book,"  by  F.  E.  Kidder. 


3o6 


BUILDING  CONSTRUCTION. 


(Ch.  VI) 


edge ;  and  where  the  full  strength  of  a  stone  is  required,  and  where 
it  is  known  to  weather  well,  it  may  with  advantage  be  set  in  this 
way  and  protected  from  the  weather  by  placing  a  molded  course 
above,  set  on  its  natural  bed. 

Floor  beams,  and  any  construction  carrying  a  live  or  moving  load, 
should  never  be  supported  on  stone  lintels.  These  formulas 
apply  to  slabs  as  well  as  to  lintels,  although  if  a  slab  has  a  bear- 
ing on  all  four  sides  its  strength  is  considerably  decreased. 

Example  I. — What  is  the  safe  distributed  load  for  a  granite  lintel 
over  a  6- feet  opening,  20  inches  in  height  and  8  inches  in  thick- 
ness? 

2  X  8  X  20^ 

Solution.— YSr^2.kmcr  load  =  p   X  100  =  106,666^  lbs. 

6 

One-sixth  of  this  gives  17,778  pounds  for  the  safe  distributed  load. 
Example  II. — What  is  the  safe  distributed  load  for  a  bluestone 
flag  of  4  feet  clear  span,  4  feet  in  width  and  4  inches  in  thickness? 

Solution. — Breaking  load  =  ^  ^  ^8  X  4  X  15Q  _  ^^  500  pounds. 

4 

As  the  load  on  the  flagstone  would  very  probably  be  a  live  or 
moving  load,  the  safe  load  should  be  only  one-tenth  of  the  breaking 
load,  or  5,760  pounds. 

6.    MEASUREMENT  AND  COST  OF  CUT- 
STONEWORK. 

317.  UNITS  OF  MEASUREMENT.^Rough  stone  from  the 
quarry  is  usually  sold  under  two  classifications,  rubble-stone  and 
dimension-stone.  Rubble  includes  the  pieces  of  irregular  size  most 
easily  obtained  from  the  quarry,  and  suitable  for  cutting  into  ashlar 
12  inches  or  less  in  height  and  about  2  feet  long.  Stone  ordered  of  a 
certain  size,  or  to  square  over  24  inches  each  way,  and  of  a  particular 
thickness,  is  called  ''dimension-stone."  The  price  of  the  latter  varies 
from  two  to  four  times  the  price  of  rubble. 

Rubble  is  generally  sold  by  the  ton  or  carload.  Footings  and 
lagging  are  usually  sold  by  the  square  foot ;  dimension-stone  by  the 
cubic  foot.  In  Boston  granite  blocks  for  foundations  are  usually 
sold  by  the  ton. 

In  estimating  on  the  cost  of  stonework  put  into  the  building,  the 
custom  varies  with  difYerent  localities,  and  even  among-  contractors 
in  the  same  city. 


MEASUREMENT    AND  COST. 


307 


Dimension-stone  footings  (that  is,  square  stones  2  feet  or  more  in 
width)  are  usually  measured  by  the  square  foot.  If  built  of  large 
rubble  or  irregular  stones  the  footings  are  measured  in  with  the 
wall,  allowance  being  made  for  the  projections  of  the  footings. 

Rubble-zi'ork  is  almost  universally  measured  by  the  perch  of  t6^ 
cubic  feet.  The  author  has  been  unable  to  find  any  locality  where 
the  legal  perch  of  24}^  cubic  feet  is  used  by  stone-masons.  In 
Philadelphia,  St.  Louis  and  some  portions  of  Illinois  22  cubic  feet 
are  called  a  perch. 

It  is  customary  to  measure  railroad  work  by  the  cubic  yard,  or 
27  cubic  feet. 

If  work  is  let  by  the  perch,  the  number  of  cubic  feet  that  are  to 
constitute  a  perch  should  be  distinctly  stated  in  the  contract,  as  the 
custom  of  the  place  would  probably  prevail  in  case  of  a  dispute. 
It  should  also  be  stated  whether  or  not  openings  are  to  be  deducted, 
because,  as  a  rule,  rubble  walls  are  figured  solid,  unless  an  opening 
exceeds  70  square  feet  in  superficial  area. 

Occasionally  nibble  is  measured  by  the  cord  of  128  cubic  feet. 

Stone  backing  is  generally  figured  the  same  as  rubble. 

Ashlar  is  almost  invariably  measured  by  the  square-foot  face,  the 
price  varying  with  the  kind  of  work  and  size  of  stones.  Openings 
are  generally  deducted,  but  the  widths  of  jambs  are  usually  measured 
in  with  the  face  work.  This  custom  varies,  however,  with  different 
localities  and  kinds  of  work.  In  common  rock-faced  ashlar  the  wall 
is  often  figured  solid,  unless  the  openings  are  of  unusual  size. 

Flagging  and  slahs  of  all  kinds  are  always  figured  by  the  square 
foot.  Curbing,  moldings,  belt-courses  and  cornices  are  usuallv 
figured  by  the  lineal  foot,  and  irregular-shaped  pieces  by  the  cubic 
foot.  All  carving  is  figured  by  the  piece.  Some  contractors  figure 
all  kinds  of  triinniings  by  the  cubic  foot,  varying  the  price  according 
to  the  amount  of  labor  mvolved.  Others  figure  the  number  of  cubic 
feet  in  all  the  stone,  to  get  the  value  of  the  rough  stone,  and  then 
figure  the  labor  separately,  so  much  per  lineal  foot  for  moldings, 
so  much  for  the  columns,  etc.,  giving  a  separate  figure  for  carving. 
This  is  the  most  accurate  method,  and  is  usually  employed  by  con- 
tractors for  granite  work.  Of  course,  considerable  experience  is 
necessary  in  order  to  know  how  much  to  allow  for  labor,  while  the 
value  of  the  stone  itself  can  be  very  easily  computed. 

318.  THE  COST  OF  STONEWORK.— The  prices  of  different 
kinds  of  stonework  vary  according  to  the  value  of  the  stone,  the 


3o8  BUILDING    CONSTRUCTION/       (Ch.  VI) 

cost  of  quarrying,  the  transportation,  the  demand,  the  prevaihng 
vvages,  the  sizes  of  the  stones,  the  amount  of  cutting,  carving  and 
dressing,  etc. 

It  is  impossible  to  give  data  for  estimating  a  cost  that  will  not 
vary  between  wide  limits,  and  any  figures  given  would  serve  only  as 
approximations  or  guides  in  forming  rough  estimates^' 

7.    SUPERINTENDENCE  OF  CUT-STONEWORK. 

319.  SUPERINTENDENCE  IN  GENERAL.— As  with  all 
other  building  operations,  the  superintendent  needs  to  be  very  watch- 
ful in  inspecting  the  cut-stonework  and  its  setting  to  prevent  defects 
and  imperfect  work  from  being  imposed  upon  him.  When  a  stone 
is  once  built  into  a  wall  it  can  be  removed  only  at  consrderable  ex- 
pense and  after  delay  and  much  vexation ;  and  it  is  therefore  im- 
portant that  all  defects  be  discovered  before  it  is  set.  The  super- 
intendent must  be  well  posted  on  the  various  ways  in  which  defects 
are  covered  up,  so  that  he  will  discover  them,  if  they  exist,  and  he 
must  have  sufficient  firmness  to  demand  that  all  unsound  or  defective 
stones  shall  be  replaced  by  sound  ones,  and  that  the  work  shall 
be  done  in  the  manner  directed  by  the  architect. 

Defects. — The  following  are  the  defects  most  likely  to  occur  in 
cut-stonework : 

Good  granites  are  liable  to  contain  local  defects,  such  as  seams, 
black  or  white  lumps  called  "knots,"  and  also  brown  stains  known 
as  sap.  Any  of  these  defects  should  be  sufficient  cause  to  reject  the 
stone.  Seams  may  be  detected  by  striking  the  stones  with  a  hammer, 
and  those  which  do  not  ring  clearly  should  be  rejected. 

In  sandstones  the  two  most  common  defects  are  "sand  holes," 
which  are  small  holes  filled  with  sand,  without  any  cementing  mate- 
rial to  prevent  the  sand  from  washing  out,  and  uneven  color.  Stones 
from  the  same  quarry  often  vary  considerably  in  color,  and  the 
superintendent  must  see  that  the  color  of  the  stone  is  uniform 
throughout. 

Patching. — Often  in  cutting  a  stone  a  small  piece  is  broken  ofif 
from  a  large  stone,  and  the  contractor,  rather  than  throw  the  stone 
away,  either  sticks  the  piece  on  again  or  cuts  out  the  fractured  part 
and  fits  in  a  new  piece.    The  pieces  are  glued  on  with  melted  shellac 


*  For  "Data  for  E?timatiiTT  Tost  of  Stonework,"  of  all  kinds,  with  average  prices  p*^d 
fP'otations  for  labor  and  rn'^*^<^'-ir)i=  sef-  discussion  under  this  heading  in  Part  III  of  the 
"Architect's  and  Builder's  Pocket-Book, "  by  F.  E.   Kidder.  . 


*     SUPERINTENDENCE.  ■  309 

and  then  rubbed  with  stone  dust  until  they  eannot  be  detected  by  a 
casual  glance,  and  it  is  necessary  for  the  superintendent  to  look  very 
closely  at  the  stones  in  order  to  be  sure  that  they  are  not  patched  in 
this  waw 

At  first  these  patches  are  hardly  noticeable  and  do  no  harm,  but 
when  the  stone  gets  wet  the  patch  becomes  conspicuous,  and  in  time 
the  shellac  in  the  joint  is  washed  away  and  the  patch  drops  off„ 

When  the  damaged  stone  is  large,  and  cannot  be  replaced  except 
at  great  expense  and  considerable  delay,  the  superintendent  might 
consent  to  have  it  patched,  but  he  should  see  that  it  is  done  correctly, 
and,  where  possible,  a  square  hole  cut  in  the  stone  and  a  correspond- 
ing piece  tightly  fitted  in,  and  then  cut  to  fit 'the  stone  or  molding. 
If  it  is  on  the  corner  of  a  stone,  the  piece  can  generally  be  dove- 
tailed, so  that  it  will  stay  in  place  without  the  aid  of  shellac.  If  any 
patched  stones  are  put  into  the  building  the  superintendent  should 
know  of  it  beforehand,  and,  as  a  rule,  it  is  wise  to  consult  the  owner 
of  the  building  about  it  before  the  stone  is  set. 

Poor  Workmanship. — In  the  cutting  of  the  stone  the  most  com- 
mon fault  to  be  found  is  poor  workmanship  or  too  coarse  a  surface. 
Naturally,  the  finer  a  surface  is  tooled  or  crandalled  the  greater  the 
expense,  and  hence  contractors  generally  finish  the  stone  with  as 
coarse  a  finish  as  they  think  the  superintendent  will  pass.  Very 
often,  also,  sufficient  care  is  not  taken  in  matching  the  ends  of 
molded  belt-courses,  cornices,  etc.  The  superintendent  should 
insist  on  having  all  the  pieces  cut  exactly  to  the  same  pattern,  and  all 
edges  true  and  free  from  nicks. 

Scant  Stone  Windozv  Sills. — It  is  not  unusual  to  find  some  window 
sills  that  are  not  of  sufficient  width  to  be  well  covered  by  the  wood 
sills.  The  back  of  the  stone  sills  should  extend  at  least  1}^  inches 
back  beyond  the  face  of  the  wood  sill,  and  the  back  of  the  wash 
should  be  cut  to  a  straight  line,  without  any  holes  or  scant  surfaces. 

Ashlar  Work. — The  ashlar,  especially  when  rock-faced,  is  apt  to 
be  too  thin  in  places,  and  to  have  very  poor  bed- joints.  The  super- 
intendent should  insist  on  having  the  bed-joints,  top  and  bottom,  at 
least  3  inches  wide  at  the  thinnest  part,  and  on  having  them  cut 
square  to  the  face  of  the  work.  He  should  also  examine  the  stones 
to  see  if  thev  have  been  cut  so  as  to  lie  on  their  natural  beds.  The 
proper  bondmg  and  anchoring  of  the  ashlar  and  trimmings  should 
also  receive  careful  attention. 

Stone  Gable  Copings. — The  anchoring  of  gable  copings  should  be 


3IO  BUILDING    CONSTRUCTION.         (Ch.  VI) 

especially  looked  after,  as  not  infrequently  such  copings  slide  out  of 
place  and  fall  to  the  ground  from  neglect  in  this  particular.  One 
wou4d  naturally  suppose  that  the  builder  himself  would  see  that  his 
work  is  done  securely,  if  not  handsomely ;  but  it  seems  to  be  a 
general  fault  among  builders  to  trust  a  good  deal  to  luck,  and  to 
use  as  few  precautions  as  possible  to  insure  it.  In  these  days,  when 
there  is  a  tendency  to  do  everything  with  a  rush,  there  are  also  many 
builders  who  are  ignorant  of  the  best  methods  of  doing  work,  or  who 
consider  them  unnecessary  and  not  "practical." 

Anchoring  Stone  Finials. — When  finials  or  similar  stones  are  cut 
into  two  pieces,  they  should  be  secured  together  by  iron  dowels  set  in 
almost  neat  Portland  cement.  The  superintendent  should  constantly 
bear  in  mind  the  fact  that  stonework  cannot  be  too  securely  anchored 
and  bonded. 

Omitting  Mortar  from  Face  loints  of  Cut-stone. — The  superin- 
tendent should  caution  the  foreman,  when  setting  arches,  columns, 
etc.,  to  keep  the  mortar  about  ^  of  an  inch  back  from  the  face  of 
the  stones.  ^lokled  arches,  particularly,  need  to  be  set  with  great 
care,  for  if  the  mortar  comes  out  to  the  face  the  joints  may  be 
a  little  full  at  the  edges  and  cause  .the  moldings  to  "sliver"  or  "spall" 
at  those  points.  It  is  not  uncommon  to  see  arch  stones  and  columns 
cracked  because  of  the  neglect  of  this  precaution. 

Pointing  of  Cut-stonezvork. — When  the  pointing  is  being  done 
the  superintendent  must  carefully  watch  the  operation  of  raking  out 
the  joints  to  receive  it.  The  old  mortar  should  be  raked  out  to  a 
depth  of  at  least  }i  of  an  inch.  If  the  work  is  not  watched,  how- 
ever, it  may  be  found  after  a  year  or  two  that  the  raking  out  of  the 
joints  was  only  partially  done,  if  not  altogether  neglected,  and  that 
the  pointing  mortar  was  struck  only  on  to  the  face  of  the  joints. 

There  will  naturally  be  manv  other  matters  in  connection  with  the 
stonework  requiring  careful  supervision  to  secure  a  good  and  dur- 
able job,  but  careful  attention  to  those  above  noted  will  lead  to  a 
pretty  thorough  inspection  of  the  whole  work, 


Chapter  Vlf. 

Bricks  and  Brickwork 


I.    BRICKS-MANUFACTURE,  KINDS  AND  USE. 

320.  GENERAL  NOTES  AND  DESCRIPTION.— Bricks  are 
more  extensively  used  in  the  construction  of  buildings  than  any 
other  material  except  wood,  and  with  the  rapidly  increasing  scarcity 
of  timber  it  is  probable  that  before  long  bricks,  terra-cotta  and 
concrete  will  largely  take  the  place  of  wood  in  many  kinds  of  con- 
struction. At  the  present  time  brick,  terra-cotta  and  concrete  archi- 
tecture is  decidedly  in  the  ascendency,  and  a  great  deal  of  capital  is 
invested  in  the  manufacture \)f  bricks  of  all  kinds,  shapes  and  colors. 

As  far  as  durability  is  concerned,  good  bricks  are  to  be  preferred 
to  stone,  as  they  are  practically  indestructible,  either  from  the  action 
of  the  weather,  from  the  acids  of  the  atmosphere  or  froiii  fire;  they 
may  be  had  in  almost  any  desirable  shape,  size  or  color,  and  are  more 
easilv  handled  and  built  into  a  wall  than  stone.  Brickwork  is  also 
much  cheaper  than  cut-stonework,  and  in  most  localities  is  less 
expensive  than  common  rubble.  Unfortunately,  however,  all  bricks 
cannot  be  classed  under  the  above  heading,  as  there  are  many  that 
are  soft  and  porous,  and  far  from  durable  when  exposed  to  damp- 
ness. Except  in  very  dry  soils  brickwork  is  not  as  suitable  as  stone- 
work for  foundations,  nor  can  it  be  used  for  piers  and  columns  that 
support  very  heavy  loads. 

As  there  are  many  different  kinds  and  qualities  of  bricks,  as  well 
as  good  and  bad  methods  of  using  them,  the  architect  must  know 
somethinp;  about  their  manufacture  and  their  characteristics;  and 
also  about  the  best  methods  of  using  them  in  order  to  properly  pre- 
pare his  designs  and  specifications  and  to  superintend  the  construc- 
tion. 

321.  COMPOSITION  OF  BRICKS.— Ordinary  building  bricks 
are  made  of  a  mixture  of  clay  and  sand  (to  which  coal  and  other 
foreign  substances  are  sometimes  added),  which  is  subjected  to 
various  processes,  differing  according  to  the  nature  of  the  materials, 

311 


312 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


the  methods  of  manufacture  and  the  character  of  the  finished 
products. 

After  being  properly  prepared  the  clay  is  put  into  molds  of  the 
desired  shape ;  then  taken  out,  dried  and  burned. 

The  Clav. — The  quality  of  a  brick  depends  principally  upon  the 
kind  of  clay  used.  The  material  generally  employed  for  making 
common  bricks  consists  of  a  sandy  clay,  or  silicate  of  alumina, 
usually  containing  small  quantities  of  lime  magnesia  and  iron  oxide. 
If  the  clay  consists  almost  entirely  of  alumina  it  will  be  very  plastic ; 
but  it  will  shrink  and  crack  in  drying,  and  warp  and  become  very 
hard  under  the  influence  of  heat. 

Silica,  when  added  to  pure  clay  in  the  form  of  sand,  prevents 
cracking,  shrinking  and  warping,  and  allows  a  partial  vitrification  of 
the  materials.  The  larger  the  proportion  of  sand  present  the  more 
shapely  and  the  more  uniform  in  texture  will  be  the  bricks.  An 
excess  of  sand,  however,  renders  the  bricks  too  brittle  and  dimin- 
ishes the  cohesion.  Twenty-five  per  cent  of  silica  is  said  to  be  a 
good  proportion. 

The  presence  of  oxide  of  iron  in  the  clay  renders  the  silica  and 
alumina  fusible  and  adds  greatly  to  the  hardness  and  strength  of 
the  bricks.  Iron  has  a  great  influence  also  upon  the  color  of  the 
bricks  (see  Article  334),  the  red  color  being  due  to  its  presence. 
A  clay  which  burns  to  a  red  color  will  make  stronger  bricks,  as  a 
rule,  than  one  whose  natural  color  when  burned  is  white  or 
yellow. 

Lime  has  a  twofold  effect  upon,  the  clay  containing  it.  It  dimin- 
ishes the  contraction  of  the  raw  bricks  in  drying,  and  it  acts  as 
a  flux  in  burning,  causing  the  grains  of  silica  to  melt,  and  thus 
bind  the  particles  of  the  bricks  together.  An  excess  of  lime  causes 
the  bricks  to  melt  and  lose  their  shape.  Again,  whatever  lime  is 
present  must  be  in  a  very  divided  state.  Lumps,  of  limestone  are 
fatal  in  a  clay  used  for  brickmaking.  When  a  brick  containing 
a  lump  of  limestone  is  burned  the  carbonic  acid  is  driven  off,  and 
the  lump  is  formed  into  quicklime  which  is  liable  to  slake  as  soon 
as  the  brick  is  wet  or  exposed  to  the  weather.  Pieces  of  quick- 
lime not  larger  than  pin-heads  have  been  known  to  detach  por- 
tions of  a  brick  and  to  split  it  to  pieces.  The  presence  of  lime 
may  be  detected  by  treating  the  clay  with  a  little  dilute  sulphuric 
acid.    If  there  is  lime  present  an  effervescence  will  take  place. 


BRICKS— MANUFACTURE.  313 

For  the  best  qnaHties  of  pressed  bricks  the  clay  is  carefully 
selected  for  both  chemical  composition  and  color;  and  very  often 
two  or  three  qualities  of  clay  from  different  sources  are  mixed 
together  to  obtain  the  .  desired  composition. 

Clays  of  especially  fine  quahty  are  often  mixed  and  shipped, 
like  other  raw  materials,  to  distant  parts  of  the  country.  ^ 

322.  MANUFACTURE,  (i)  HAND-MADE  BRICKS.— Most 
of  the  common  bricks  used  in  this  country,  especially  in  the  smaller 
towns  and  cities,  are  still  made  by  hand.  The  process  consists  of 
throwing  the  clay  into  a  circular  pit,  where  it  is  mixed  with  water 
and  tempered  with  a  tempering  wheel  worked  by  horse  power  until 
it  becomes  soft  and  plastic,  and  then  taking  it  out  and  pressing 
it  into  molds  by  hand.  Unless  the  clay  contains  sufficient  sand 
already,  additional  sand  is  added  to  it  as  it  is  put  into  the  pit, 
and  coal  dust  or  sawdust  is  often  added  to  assist  the  burning. 
In  some  localities  screened  cinders  are  mixed  with  the  clay. 

In  molding  bricks  by  hand  the  molds  are  dipped  in  either  water 
or  fine  sand  to  prevent  the  bricks  from  adhering  to  the  molds. 
If  the  molds  are  dipped  in  water  the  process  is  called  ''slop-mold- 
ing," and  if  in  sand  the  bricks  are  called  "sand-struck."  The 
latter  method  gives  cleaner  and  sharper  bricks  than  those  pro- 
duced by  "slop-molding." 

After  being  shaped  in  the  meld  the  bricks  are  laid  in  the  sun, 
or  in  a  dry-house,  to  dry  for  three  or  four  days,  after  which  they 
are  stacked  in  kilns  and  then  fired.  ^ 

When  the  green  bricks  are  dried  in  the  open  air  they  are  occa- 
sionally caught  in  a  showier,  which  gives  them  a  pitted  effect, 
that  is  generally  considered  Undesirable.  Unless  the  edges  are 
much  rounded,  however,  this  does  'not  affect  the  strength  of  the 
bricks,  and  they  may  be  used  in  the  interior  of  walls. 

323.  MANUFACTURE.  (2)  MACHINE-MADE  BRICKS.— 
Where  bricks  are  made  on  a  large  scale  the  work  is  now  done 
almost  entirely  by  machinery,  commencing  with  the  mining  of  the 
clay  by  steam-shovels  and  ending  by  the  burning  in  patent  kilns. 

Machines  in  great  variety  are  now  made  for  preparing  the  clay 
and  for  making  the  raw  bricks.  They  differ  more  or  less  widely 
in  construction  and  principle,  but  may  be  divided  into  three  classes, 
according  to  the  methods  of  manufacture  for  which  they  are 
adapted. 


314 


BUILDING  CONSTRUCTION.        (Cii.  VII) 


There  are  practically  three  processes  employed  in  making  bricks, 
viz.:  a.  The  soft-mud  process;  h.  The  stiff-mud  process,  and  c.  The 
dry-clay  process.  The  machines  are  also  classed  under  these  same 
headings. 

The  general  processes  are  as  follows : 

a.  The  Soft-mud  Process. — This  is  essentially  the  same  proc- 
ess as  that  employed  when  the  bricks  are  made  by  hand.  When 
machinery  is  used  the  various  steps  are  about  as  follows :  As 
the  clay  is  brought  from  the  bank  it  is  thrown  into  a  pit  (about 
6  feet  deep  and  8  by  I2  feet  in  area)  lined  with  planks.  Water 
is  then  turned  into  this  pit  and  the  clay  allowed  to  soak  for  twenty- 
four  hours.  Three  pits  are  generally  provided,  so  that  the  clay 
in  one  may  be  soaking  while  the  second  is  being  emptied  and 
the  third  being  filled.  If  coal-dust  is  to  be  mixed  with  the  clay 
it  is  thrown  into  the  pit  in  the  proper  proportions.  After  soaking 
twenty-four  hours  in  the  pit  the  clay  is  thrown  out  on  an  end- 
less chain,  which  carries  it  along  to  the  machinery,  into  which 
it  falls.  The  upper  part  of  a  soft-clay  machine  contains  a  revolv- 
ing shaft,  to  which  arms  are  affixed.  These  arms  break  up  and 
thoroughly  work  the  soft  clay,  which  falls  to  the  bottom  of  the 
machine,  where  revolving  blades  force  it  forward ;  and  a  plunger 
working  up  and  down  then  forces  it  into  a  mold  placed  under  an 
opening.  The  filled  mold  is  then  drawn  or  forced  out  on  a 
shelf  or  table  and  another  mold  placed  under  the  opening.  There 
are  several  types  of  machines,  but  they  all  work  on  about  this 
plan.  Sometimes  the  clay  is  worked  in  a  pug-mill  before  being 
thrown  into  the  machine. 

After  being  drawn  from  the  machines  the  filled  molds  are  emp- 
tied by  hand  and  the  bricks  taken  to  the  dry-sheds.  For  drying 
soft-mud  bricks  the  "pallet"  system  is  generally  employed.  The 
"pallets"  are  thin  boards  about  I2  by  24  inches  in  size.  The 
bricks  are .  placed  on  these,  which  are  then  put  upon  racks, 
arranged  so  that  the  air  will  have  free  circulation.  The  stacks 
should  always  be  protected  by  a  low  roof  covering. 

b.  The  Stiff-mud  Process. — The  essential  difiference  between 
this  process  and  the  foregoing  is  that  in  the  stiflf-mud  process  the 
clay  is  first  ground,  or  disintegrated,  and  only  enough  water  added 
to  make  a  stiff  mud.    This  mud,  after  being  pugged,  is  forced 


BRICKS— MANUFACTURE. 


315 


through  a  die  in  a  continuous  stream,  whose  cross-section  is  the 
size  of  a  brick,  and  the  bricks  are  then  cut  off. 

The  process  varies  more  or  less  in  different  yards  and  with  dif- 
ferent clays;  but  when  most  thoroughly  carried  out  the  various 
steps  in  their. order  are  as  follows:  First,  the  mining  of  the  clay; 
secondly,  the  breaking  up  of  the  lumps  (generally  in  a  pug-mill)  ; 
thirdly,  the  grinding  of  the  clay,  either  in  a  separate  pug-mill  or  in 
the  machine,  and  fourthly,  the  passing  of  the  clay  through  the 
machine  and  the  cutting  off  of  the  bricks. 

There  are  two  primary  types  of  stiff-mud  brick-machines,  viz. : 
The  auger  type  and  the  plunger  type.  Of  these  the  auger 
machines  are  the  more  numerous  and  are  generally  considered 
the  more  satisfactory.  The  auger  machine  consists  of  a  closed 
tube  of  cylindrical  or  conical  shape,  in  which,  on  the  line  of  the 
axis  of  the  tube,  a  shaft  revolves.  To  this  shaft  the  auger  and 
auger  knives  are  attached.  The  knives  are  arranged  so  as  to  cut 
and  pug  the  clay  and  force  it  forward  into  the  auger.  The  func- 
tion of  the  auger  is  to  compress  and  shape  the  clay  and  force  it 
through  the  die.  When  the  clay  passes  through  the  die  it  is 
compressed  as  much  as  i:.  possible  in  its  semi-plastic  condition. 
The  opening  in  the  die  13  made  the  same  size  as  either  the  end 
or  the  side  of  a  brick,  and  a  continuous  bar-shaped  stream  of 
clay  is  constantly  forced  through  it  and  on  to  a  long  table. 
Various  automatic  arrangements  are  provided  for  cutting  up  this 
bar  into  pieces  the  size  of  a  brick.  If  the  section  of  the  bar  is 
the  same  size  as  the  end  of  a  brick,  the  bricks  are  called  "end- 
cut"  ;  if  the  section  of  the  bar  is  that  of  the  side  of  a  brick,  the 
bricks  are  called  ''side-cut."  With  the  end-cut  bricks  the  clay 
may  issue  from  the  machine  in  one,  two,  three  or  even  four 
streams. 

From  the  cut-off  table  the  green  bricks  pass  to  the  off-bearing 
belts,  from  which  they  are  taken  to  the  repressers  or  driers. 

In  the  plunger  brick-machine  the  clay  is  forced  into  a  closed  box 
or  pressing-chamber,  in  which  a  piston  or  plunger  reciprocates  and 
forces  the  clay  through  the  die.  The  action  of  this  type  of  machine 
must  of  necessity  be  intermittent.  When  the  plunger  machine  is 
used  the  clay  is  generally  tempered  in  a  pug-mill  before  passing  to 
the  machine.  ^ 

c.  The  Dry-clay  Process. — This  process  is  especially  adapted  to 


3i6 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


clays  that  contain  only  about  7  per  cent  of  moisture  as  they  come 
from  the  banks,  the  clays  being  apparently  perfectly  dry.  Wet 
clays  are  sometimes  dried  and  then  subjected  to  the  same  treat- 
ment, but  the  expense  of  drying  materially  increases  the  cost  of 
manufacture. 

The  various  operations  generally  employed  in  making  bricks  by 
this  process  may  be  briefly  described  as  follows :" 

The  first  step  is  the  mining  of  the  clay,  which  may  be  done  either 
by  hand  or  with  steam-shovels,  as  circumstances  may  determine. 
After  being  mined  the  clay  is  generally  stored  under  cover,  in 
order  to  have  a  supply  always  on  hand,  and  also  to  permit  of 
further  drying  and  disintegrating.  Sometimes,  however,  the  clay 
is  taken  directly  from  the  bank  to  the  dry-pans. 

Probably  most  of  the  dry-press  bricks  are  made  from  two  or 
more  grades  of  clay,  mixed  in  proportions  determined  by  trial 
as  it  is  thrown  into  the  dry-pans. 

From  the  dump  the  clay  is  thrown  into  a  dry-pan,  which  is  a 
circular  machine  about  4  feet  in  diameter  and  2  feet  deep,  with  a 
perforated  metal  bottom.  In  this  machine,  or  pan,  as  it  is  called, 
are  two  wheels,  which  constantly  revolve  on  a  horizontal  axis  and 
grind  the  clay  between  them  and  the  bottom  of  the  pan,  the  pan 
itself  revolving  at  the  same  time.  The  clay  as  it  is  ground  passes 
through  holes  in  the  bottom  of  the  pan  and  falls  to  a  wide  belt, 
which  carries  it  above  an  inclined  screen,  upon  w^hich  it  falls. 
The  portions  of  the  clay  that  are  ground  fine  enough  fall  through 
the  screen  and  on  another  belt,  and  the  coarser  particles  roll  into 
the  dry-pan,  to  be  again  ground  and  carried  to  the  screen. 

The  belt  which  receives  the  fine  clay  from  the  screen  carries  it 
to  a  mixing-pan,  a  machine  contrived  to  thoroughly  mix  the  par- 
ticles of  the  clay.  From  the  mixing-pan  the  clay  falls  into  the 
hopper  of  the  pressing  machine,  and  from  the  hopper  it  falls  into 
the  molds,  where  it  is  subjected  to  great  pressure,  and  compressed 
to  the  size  of  the  bricks.  The  pressed  bricks  are  then  pushed  out 
and  on  to  a  table.  From  the  table  of  the  machine  the  bricks  are 
taken  by  hand,  placed  on  a  barrow,  or  car,  and  transferred  to  the 
kiln. 

Different  manufacturers  vary  these  operations  somewhat,  but 
the  processes,  and  also  the  machines,  used  in  manufacturing  pressed 
bricks  are  essentially  like  the  above. 


BRICKS— MANUFACTURE. 


317 


The  pressing  machines  are  so  ccMistrticted  that  the  loose  clay  is 
made  to  evenly  fill  steel  boxes  of  the  widths  and  lengths  of  the 
intended  bricks,  but  much  deeper.  Into  these  boxes  plungers  are 
forced,  which  compress  the  clay  until  the  desired  thicknesses  are 
reached,  when  the  plungers  stop.  If  the  clay  falls  more  com- 
pactly into  one  box,  or  mold,  than  into  another,  the  bricks  from 
the  first  mold  will  be  the  denser,  as  the  plunger  falls  just  so  far, 
no  matter  how  much  clay  is  in  the  mold. 

Molded  bricks  are  made  in  exactly  the  same  way,  the  only  dif- 
ference being  that  the  boxes  are  made  to  give  the  desired  shape 
of  bricks. 

Most  of  the  pressed-brick  machines  admit  a  small  jet  of  steam 
into  the  clay  to  slightly  moisten  it  just  before  it  passes  into  the 
molds. 

Bricks  made  by  this  process  are  very  dense  and  generally  show  a 
high  resistance  to  compression ;  but  the  general  opinion  is  that 
the  particles  do  not  adhere  as  well  as  when  the  clay  is  tempered^ 
and  that  -dry-pressed  bricks  will  not  prove  as  enduring  as  soft- 
mud  bricks,  although  the  former^  are  now  more  extensively  used 
for  face-bricks. 

When  the  term  ''pressed  bricks"  is  used  it  should  refer  to  bricks; 
made  by  the  dry  process,  although  many  so-called  pressed  bricks,, 
or  face-bricks,  are  made  by  re-pressing  soft-mud  bricks. 

324.  COMPARISON  OF  SOFT-MUD  AND  STIFF-AIUD 
BRICKS. — Soft-mud  bricks  are  made  under  little  or  no  pressure,, 
and  are,  therefore,  not  as  dense  as  the  stiff-mud  bricks.  It  Is. 
claimed,  however,  that  in  the  soft-mud  bricks  the  particles  adhere 
more  closely,  and  that  when  they  are  properly  made  and  burned 
they  are  the  most  durable  of  all  bricks.  Soft-mud  bricks,  after 
having-  lain  in  a  foundation  on  the  shore  of  a  river  for  fiftv-four 
years,  were  found  in  as  perfect  condition  as  when  laid.  Soft- 
mud  bricks  are  also  generally  more  perfect  in  shape  than  stiff-mud 
bricks  and  better  adapted  for  painting. 

Stiff-mud  bricks,  owing  to  the  nature  of  the  clay  and  the  details 
of  manufacture,  often  contain  laminations,  or  planes  of  separation, 
which  more  or  less  weaken  them. 

Those  made  by  the  plunger  machine  also  sometimes  contain  voids 
caused  by  the  air  which  occasionally  passes  with  the  loose  clay 
into  the  pressure  chamber,  and  being  unable  to  escape,  passes  out 


3i8 


BUILDING  CONSTRUCTION. 


(Ch.  VII) 


again  with  the  clay  stream  whi^h  it  renders  more  or  less  imperfect.  - 
The  manufacture  of  stifif-mud  bricks,  however,  is  constantly  - 
increasing. 

In  some  localities  soft-mud  bricks  are  the  cheaper;  in  others  the 
stiff-mud  bricks  have  the  advantage.  The  difference  in  cost,  how- 
ever, is  usually  very  slight. 

The  soft-mud  bricks  take  longer  to  dry,  but  are  more  easily 
burned. 

325.  RE-PRESSING.— Both  soft  and  stiff-mud  bricks  are  often 
re-pressed  in  a  separate  machine.  Re-pressing  reshapes  the  bricks, 
rounds  the  corners  if  required,  trues  them  in  outline  and  makes 
a  considerable  improvement  in  their  appearance.  Properly  formed 
stiff-mud  bricks,  however,  are  not  improved  in  structure  by 
re-pressing. 

326.  DRYING  AND  BURNING.— Bricks  made  by  the  soft- 
mud  process  always  have  to  be  dried  before  being  placed  in  the 
kiln ;  those  made  by  the  stiff-mud  process  are  generally,  although 
not  always,  stacked  in  a  dry-house  from  twelve  to  twenty-four 
hours.  The  drying  of  the  bricks  i,s  an  important  process,  and  where 
they  are  manufactured  on  a  large  scale  the  drying  is  generally 
accomplished  by  artificial  means. 

After  being  sufficiently   dried  they  are  stacked   in   kilns  and 
burned. 

Three  types  of  kilns  are  used  for  burning  bricks,  viz.:  Up-draft, 
dozvn-draft  and  continuous  kilns. 

327.  UP-DRAFT  KILNS. — These  kilns  were  almost  uni- 
versally used  in  this  country  for  burning  bricks  previous  to  1870, 
and  are  still  used  more  than  either  of  the  other  types,  especially 
in  small  yards  where  the  bricks  are  manufactured  by  hand. 

The  old-fashioned  up-draft  kilns  are  nothing  but  the  bricks  them- 
selves built  into  piles  from  20  to  30  feet  wide,  from  30  to  40  feet 
long  and  from  12  to  15  feet  high.  The  sides  and  ends  of  the 
piles  are  plastered  with  mud  to  keep  in  the  heat,  and  the  tops 
are  generally  covered  with  dirt  and  sometimes  protected  with  shed 
roofs. 

The  bricks  are  piled  so  as  to  form  a  row  of  arched  openings 
extending  entirely  across  the  kilns,  and  in  these  openings  the  fires 
are  built.  The  dried  bricks  are  loosely  piled  above  these  arches, 
and  as  the  kilns  are  burnt,  those  nearest  the  fire  are  so  intensely 


BRICKS— MANUFACTURE. 


heated  that  they  become  vitrified,  while  those  at  the  tops  of  the 
kihis  are  but  shghtly  burned,  with  a  gradual  graduation  of  hard- 
ness between  them.  It  is  from  this  difference  in  the  burning  that 
the  terms  "arch-brick,"  "red  brick"  and  "salmon  brick"  originated. 
As  the  natural  tendency  of  heated  air  is  to  rise  and  to  j^roduce 
a  draft,  its  direction  is  upward,  and  hence  the  name  "up-draft'* 
kiln. 

The  modern  up-draft  kilns  have  permanent  sides  made  of  from 
12  to  i6-inch  brick  walls  laid  in  mortar,  and  heat  is  generated  in 
ovens  with  iron  grates  built  outside  of  the  permanent  walls.  Only 
flames  and  heat  enter  the  kilns  through  fire  passages  in  the  walls 
connecting  the  furnaces  with  the  kilns  proper.  The  tops  of  the 
kilns,  also,  are  paved  with  smooth,  hard  bricks,  laid  so  as  to  form 
close  covers  that  can  be  opened  or  closed  as  desired.  The  bricks 
are  piled  in  the  same  way  as  described  above,  the  arches  being- 
left  opposite  the  furnaces.  With  these  improvements  the  bricks 
can  be  much  more  evenly  burned  and  with  a  smaller  consump- 
tion of  fuel.  The  burning  of  a  kiln  of  bricks  requires  about  ix 
week.  After  the  fires  have  been  burning  a  sufficient  length  of 
time  they  are  permitted  to  go  out,  and  all  the  outside  openings  are 
tightly  closed  to  keep  out  the  cold  air,  and  thus  allow  the  bricks 
to  cool  gradually.  It  requires  much  skill  and  practice  to  burn  a 
kiln  of  bricks  successfully. 

328.  DOWN-DRAFT  KILNS.— Kilns  of  this  class  require 
permanent  walls  and  tight  roofs.  The  floors  must  be  open  and 
connected  by  flues  with  chimneys  or  stacks.  These  kilns  are  more 
often  made  circular  in  plan  and  in  the  shape  of  beehives,  although 
they  are  also  made  rectangular  in  plan.  The  heat  is  generated  in 
ovens  built  outside  of  the  main  walls,  and  the  flames  and  gases  enter 
the  kilns  through  vertical  flues,  carried  to  about  half  the  height 
of  the  kilns.  The  heat,  therefore,  practically  enters  the  kilns  at 
the  top  and  being  drawn  downward  by  the  draft  produced  in  the 
chimneys,  passes  through  the  piles  of  bricks  and  the  openings  in 
the  floors  into  the  flues  beneath,  and  hence  to  the  chimneys  or 
shafts.  It  is  claimed  that  all  kinds  of  clay  wares  can  be  burned 
more  evenly  in  drawn-draft  kilns.  Terra-cotta  and  pottery  are 
almost  always  burned  in  such  kilns.  For  terra-cotta  and  pottery 
the  beehive-shapes  are  generally  used,  several  kilns  being  con- 
nected with  one  stack. 


320  BUILDIXG  COXSTRUCTfOK.        (Ch..  VII) 

329.  CONTINUOUS  KILNS.— These  derive  their  name  from 
the  fact  that  the  heat  is  continuous  and  the  kihis  kept  continuously 
l:)urning.  Continuous  kilns  are  very  different,  both  in  construction 
and  working,  from  the  other  two  types,  and  the  expense  of  build- 
ing- them  is  also  relatively  great.  There  are  various  types  of 
continuous  kilns,  each  being  protected  by  letters  patent. 

The  most  common  type  is  that  of  two  parallel  brick  tunnels  con- 
nected at  the  ends.  The  outer  walls  are  sometimes  8  feet  thick  at 
the  bottom  and  4  feet  thick  at  the  top.  Numerous  flues  are  built 
in  these  walls.  The  coal  in  continuous  kilns  is  put  in  at  the  top. 
The  bricks  are  piled  in  the  kilns  in  sections,  which  are  separated 
by  paper  partitions,  each  section  being  provided  with  about  four 
-openings  in  the  top  for  putting  in  the  coal.  After  a  kiln  is. started, 
one  section  at  a  time  is  kept  burning,  and  the  heated  gases  are 
drawn  through  the  next  section  so  as  to  dry  the  bricks  in  that 
section  before  burning.  There  are  often  twenty  or  more  sections 
in  one  kiln,  and  while  some  sections  are  burning  and  some  drying, 
.others  are  being  filled  and  others  cooling  or  being  emptied. 

Continuous  kilns  require,  a  powerful  draft  to  make  them  work 
-successfully,  and  this  draft  is  generally  provided  by  tall  stacks. 

The  principal  advantages  claimed  for  continuous  kilns  are  that 
they  take  less  fuel  to  burn  the  bricks,  and  that  a  greater  percentage 
of  No.  I  bricks  are  obtained  than  with  other  kilns.  The  question 
of  the  kind  of  kiln  to  be  used,  however,  is  principally  one  of 
•economy  to  the  manufacturer,  as  it  makes  no  particular  dift'erence 
to  the  architect  in  what  kind  of  a  kiln  the  bricks  are  burned. 

330.  GLAZED  AND  ENAMELLED  BRICKS.— These  terms 
;are  used  to  designate  bricks  that  have  a  glazed  surface,  the  term 
^'enamelled"  being  applied  indiscriminately  to  all  bricks  having  such 
a  surface. 

There  is,  however,  quite  a  difference  between  glazed  bricks  and 
enamelled  bricks.  The  true  enamel  is  fused  into  the  clay  without 
an  intermediate  coating,  and  the  enamel  is  opaque  in  itself ;  whereas 
a  glaze  is  produced  by  first  covering  the  clay  with  a  "slip"  and 
then  with  a  second  coat  of  transparent  glaze  resembling  glass. 

In  the  manufacture  of  glazed  bricks  the  unburnt  bricks  are  first 
coated  on  the  sides  which  are  to  be  glazed  with  a  thin  layer  of 
"slip,"  which  is  a  composition  of  ball-clay,  kaolin,  flint  and  feld- 
spar.   The  slip  adheres  to  and  covers  the  clay,  and  at  the  same 


BRICKS— MANUFACTURE. 


321 


time  receives  and  holds  the  glaze.  The  glaze,  which  is  put  on  very 
thin,  is  composed  of  materials  which  fuse  at  about  the  temperature 
required  to  melt  cast-iron,  and  which  leave  a  transparent  body 
covering  the  white  slip.  With  glazed  bricks  it  is  the  slip  that  gives 
them  their  color ;  and  as  the  slip  covers  them  they  may  be  either 
red  or  white.    Not  all  bricks,  however,  are  suitable  for  glazing. 

Enamelled  bricks  are  made  from  a  particular  quality  of  clay,  gen- 
erally containing  a  considerable  proportion  of  fire-clay.  The  enamel 
may  be  applied  either  to  the  unburned  bricks  or  to  the  bricks  after 
they  are  burned.  The  latter  method,  it  is  claimed,  produces  the 
most  perfect  bricks. 

In  burning,  the  enamel  fuses  and  unites  with  the  body  of  the 
brick ;  but  as  it  does  not  become  transparent,  each  brick  shows  its 
own  color. 

The  manufacture  of  genuine  enamelled  bricks  is  a  much  more 
expensive  operation  than  that  of  glazed  bricks,  besides  involving 
very  difficult  processes.  For  this  reason  the  glazing  process  is 
the  one  generally  employed,  both  in  this  country  and  in  England. 

It  is  claimed  that  enamelled  bricks  are  more  durable  than  glazed 
bricks  and  that  they  will  not  chip  or  peel  so  readily.  Enamel  also 
shows  a  purer  white. 

Enamelled  surfaces  may  be  distinguished  from  those  which  are 
simply  glazed  by  chipping  off  pieces  of  the  bricks.  Glazed  bricks 
show  the  layer  of  slip  between  the  body  and  the  glaze,  while 
enamelled  bricks  show  no  line  of  demarcation  between  the  body 
and  the  enamel. 

After  the  bricks  are  in  the  wall  none  but  an  expert  can  dis- 
tinguish between  the  two  kinds.  Probably  most  of  the  so-called 
enamelled  bricks  that  have  been  used  in  this  country  are  really 
glazed. 

Each  brick  is,  of  course,  enamelled  or  glazed  only  on  one  face, 
or  one  face  and  one  end.  The  color  is  generally  white,  although 
light  blue  and  some  other  colors  can  be  obtained. 

Until  quite  recently  most  of  the  glazed  bricks  used  in  this 
country  were  imported  from  England,  'but  there  are  now  many 
factories  in  this  country  making  them,  and  they  produce  a  very 
large  percentage  of  all  the  glazed  bricks  now  used  in  the  United 
States. 

Enamelled  bricks  generally  differ  in  size  from  ordinary  bricks. 


322 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


The  sizes  of  the  English  bricks  are  3  inches  by  9  inches  by  4^/^ 
inches.  Part  of  the  American  factories  adhere  to  the  EngHsh 
sizes,  while  others  make  the  regular  American  sizes. 

The  American  glazed  bricks  are  now  more  nearly  perfect  than 
when  first  put  on  the  market,  aiid  appear  to  be  giving  satisfaction. 

The  genuine  enamelled  bricks  are  just  as  good  for  exterior  as 
for  interior  use.  They  will  stand  the  severest  climatic  changes, 
and  may  be  used  in  any  climate  and  in  any  situation.  They  are 
also  fire-proof. 

Both  glazed  and  enamelled  bricks  reflect  light,  acquire  no  odor, 
are  impervious  to  moisture  and  form  a  finished  and  highly  orna- 
mental surface. 

Use. — Glazed  and  enamelled  bricks,  on  account  of  the  above 
properties,  are  very  desirable  for  facing  the  walls  of  interior  courts, 
elevator  shafts,  toilet-rooms,  etc.,  and  especially  for  use  in  hospitals. 
They  may  be  used  also  with  good  effect  in  public  waiting-rooms, 
corridors,  markets,  groceries  and  butter  stores,  and  wherever  clean, 
light  and  non-absorbent  surfaces  and  those  which  will  stand 
drenching  with  water  are  required. 

331.  PAVING  BRICKS. — The  introduction  of  brick  paving 
for  streets  has  led  to  the  manufacture  of  this  class  of  bricks  on 
an  extensive  scale. 

Paving  bricks  do  not  strictly  come  within  the  province  of  the 
architect ;  but  as  he  may  have  occasion  to  use  such  bricks  for 
paving  driveways,  etc.,  it  is  well  for  him  to  know  something  about 
them. 

Thin  paving  bricks  are  also  sometimes  used  for  paving  flat  roofs 
of  office-buildings,  apartment-houses,  etc. 

Paving  bricks  are  commonly  made  by  the  stifT-clay  process,  and 
the  bricks,  after  being  cut  from  the  bar,  are  generally,  although 
not  always,  re-pressed  to  give  them  a  better  shape.  The  clay  used 
for  making  these  bricks  is  generally  shale,  almost  as  hard  as  rock, 
although  it  ,  is  sometimes  found  in  a  semi-plastic  condition.  With 
the  shale  a  certain  proportion,  often  30  per  cent,  of  fire-clay  is 
generally  added. 

The  principal  difference  in  the  manufacture  of  paving  bricks  and 
common  building  bricks  is  in  the  burning.  Paving  bricks,  to  stand 
the  frost  and  wear,  must  be  burned  to  vitrification,  or  until  the 
particles  of  the  body  have  been  united  in  chemical  combination  by 


BRICKS— MANUFACTURE,  323 


means  of  heat.  Besides  being  vitrified,  paving  bricks  are  also 
annealed,  or  toughened,  by  controlhng  the  heat  and  permitting  the 
bricks  to  cool  under  certain  conditions. 

Paving  bricks,  in  order  to  resist  the  wear  and  disintegration  to 
which  they  are  exposed  in  streets  or  driveways,  or  even  on  roofs, 
must  be  homogeneous  and  compact  in  texture,  and  must  be  vitri- 
fied and  tough.  They  should  be  free  from  loose  lumps  of 
uncrushed  clay,  extensive  laminations  and  fine  cracks  or  checks 
of  more  than  superficial  character  or  extent ;  and  they  should  not 
be  so  distorted  as  to  lie  unevenly  in  the  pavement.  They  should 
be  free  from  lime  or  magnesia  in  the  form  of  pebbles,  and  should 
show  no  signs  of  cracking  or  spalling  after  remaining  in  water 
ninety-six  hours.  They  should  have  a  crushing  strength  of  not 
less  than  8,000  pounds  per  square  inch,*  and  a  modulus  of  rupture 
of  from  1,800  to  2,500  pounds  per  square  inch. 

The  best  test  of  vitrification  is  that  of  porosity.  A  common 
hard-burned  brick  may  be  very  dense  and  strong  and  still  absorb 
from  10  to  15  per  cent  of  water.  The  same  brick  when  vitrified 
will  absorb  much  less  water. 

Engineers,  when  specifying  bricks  for  pavements,  generally  limit 
the  absorption  to  3  or  4  per  cent,  the  bricks  being  first  dried  to  212 
degrees  Fahr.  It  is  claimed,  however,  that  a  brick  may  be  vitri- 
fied and  still  absorb  as  high  as  6  or  8  per  cent,  owing  to  its  con- 
taining considerable  air  spaces.  The  density  or  specific  gravity 
also  gives  a  valuable  idea  of  the  degree  of  vitrification  of  paving 
bricks.  Great  density  or  high  specific  gravity  usually  indicates 
durability. 

For  testing  the  toughness  and  resistance  to  wear  under  the 
horses'  feet,  a  machine  resembling  a  barrel  and  called  a  "rattler" 
is  used.  Several  bricks  together  with  pieces  of  scrap  iron  are  put 
into  the  rattler,  which  is  then  revolved  rapidly  for  a  given  length 
of  time.  The  amount  that  the  bricks  lose  in  weight  is  taken  as 
the  test  of  their  durability. 

It  is  claimed  by  good  authorities  that  the  rattler  test  when  prop- 
erly conducted  is  the  most  important  test  for  durability,  and  that 
any  bricks  which  will  successfully  withstand  this  test  will  be  found 
satisfactory. 

332.    FIRE-BRICKS. — Fire-bricks  are  used  in  places  where  a 

*■  H.  A.  Wheeler,  E.  M.,  in  the  Clay  Worker,  August,  1895. 


324' 


BUILDIXG  CONSTRUCTION.        (Ch.  VII) 


very  high  temperature  is  to  be  resisted,  as  in  the  Hning  of  furnaces, 
fireplaces  and  tall  chimneys.  The  ordinary  fire-bricks  used  for  the 
above  purposes  are  made  from  a  mixture  of  about  50  per  cent  raw 
flint  clay  and  50  per  cent  plastic  clay,  the  proportion  varying  with 
different  manufacturers.  The  bricks  are  made  both  by  the  stiff- 
mud  and  dry-press  processes,  and  also  by  the  soft-mud  process 
with  hand  molding.  It  is  claimed  that  the  last  process  gives  the 
most  perfect  bricks. 

Fire-bricks,  to  admit  of  rapid  absorption  or  loss  of  heat,  should 
be  open-grained  or  porous,  and  at  the  same  time  free  from  cracks. 
They  should  also  be  uniform  in  size,  regular  in  shape,  homogene- 
ous in  texture  and  composition,  easily  cut  and  infusible. 

Fire-bricks  are  generally  larger  than  the  ordinary  building  bricks. 

333.  CLASSES  OF  BUILDING  BRICKS.— Common  Bricks, 
— This  term  includes  all  those  bricks  which  are  intended  simply 
for  constructional  purposes,  and  with  which  no  especial  pains  are 
taken  in  their  manufacture.  There  are  three  grades  of  common 
bricks,  determined  by  their  position  in  the  kiln. 

Arch-bricks  or  hard  bricks  are  those  just  over  the  arch,  and 
which,  being  near  the  fire,  are  usually  heated  to  a  high  tempera- 
ture and  often  vitrified.  They  are  very  hard,  and  if  not  too  brittle 
are  the  strongest  bricks  in  the  kiln.  They  are  often  baldly  warped, 
so  that  they  can  only  be  used  in  footings  and  in  the  interior  of 
walls  and  piers. 

Red  or  zvcU-biirncd  bricks  should  constitute  about  half  the  bricks 
in  the  ordinary  up-draft  kiln ;  and  when  made  of  clay  containing 
iron  they  should  be  of  a  bright  red  color.  For  general  purposes 
they  constitute  the  best  bricks  in  the  kiln. 

Salmon  or  soft  bricks  are  those  which  form  the  top  of  the  kiln 
and  are  usually  underburned.  They  are  too  soft  for  heavy  work 
or  for  piers,  though  they  may  be  used  for  filling  in  light  walls  and 
for  lining  chimneys. 

The  strength  and  hardness  of  common  bricks  of  all  grades  vary 
greatly  with  the  locality  in  which  they  are  made  on  account  of  the 
difference  in  the  clay.  Some  of  the  salmon  bricks  of  New  England 
are  fully  as  hard  and  strong  as  the  red  bricks  of  other  localities, 
particularly  the  West.  As  the  color  of  bricks  may  be  due  more 
to  the  presence  or  absence  of  iron  than  to  the  burning,  it  cannot  . 
be  used  as  an  absolute  guide  to  their  quality. 


4 


BRICKS— MANUFACTURE.  325 

Stock  bricks  arc  hand-made  bricks  which  are  intended  for  face- 
work,  and  with  which  greater  care  is  taken  in  the  manufacture  and 
burning  than  wath  common  bricks.  In  the  East  they  are  some- 
times called  facc-bricks. 

The  expressions  pressed  bricks  or  face-bricks  generally  refer  to 
bricks  that  are  made  in  a  dry-press  machine,  or  that  have  been 
re-pressed.  They  are  usually  very  hard  and  smooth,  with  sharp 
angles  and  corners  and  true  surfaces ;  and  they  may  be  either 
stronger  or  weaker  than  common  bricks,  according  to  the  character 
of  the  clay  and  the  extent  to  which  they  are  burned.  Pressed 
bricks  are  not  usually  burned  as  hard  as  are  common  bricks,  and 
they  are,  therefore,  sometimes  not  as  durable.  Pressed  bricks 
cost  from  two  to  five  times  as  much  as  common  bricks,  and  are, 
therefore,  generally  used  only  for  the  facings  of  walls. 

Molded  bricks,  arch-bricks  and  circle  bricks  are  special  forms  of 
pressed  bricks.  A  great  variety  of  molded  or  ornamental  bricks 
are  now  made,  by  means  of  which  moldings  and  cornices  may  be 
built  entirely  of  bricks.  Most  of  the  companies  manufacturing 
pressed  bricks  will  also  make  any  special  shapes  of  bricks  from  an 
architect's  designs.  Arch-bricks  are  made  in  the  form  of  truncated 
wedges  and  are  used  for  the  facing  of  brick  arches.  They  can 
be  made  for  any  radius  required.  Circle  bricks  are  made  for  facing 
the  walls  of  circular  towers,  bays,  etc.  The  radius  of  the  bay 
should  be  given  when  ordering  these  bricks. 

Radial  Blocks. — Radial  blocks  for  chimney  construction  are  made 
in  several  forms  and  are  designed  to  fit  the  curve  and  radius  of  the 
chimney  in  which  they  are  used,  their  purpose  being  to  reduce  the 
area  and  number  of  mortar  joints  and  increase  the  bond.  Properly 
designed  blocks  make  much  stronger  chimneys  than  can  be  made 
with  ordinary  bricks.    See  Article  374. 

334.  COLOR  OF  BRICKS. — The  color  of  common  bricks 
depends  largely  upon  the  composition  of  the  clay  and  the  tem- 
perature to  which  it  is  raised.  Pure  clay,  free  from  iron,  will 
burn  white,  but  the  color  of  white  bricks  is  generally  due  to  the 
presence  of  lime.  Iron  in  the  clay  produces  a  tint  which  varies  from 
light  yellow  to  orange  and  red,  according  to  the  proportion  of  iron 
contained  in  the  clay.  A  clear  bright  red  is  produced  by  a  large 
proportion  of  oxide  of  iron,  and  a  still  greater  proportion  of  iron 
gives  a  dark  blue  or  purple  color.    When  the  bricks  are  intensely 


326 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


heated  the  iron  mehs  and  runs  through,  causing  vitrification  and 
giving  increased  strength.  The  presence  of  iron  and  hme  pro- 
duces a  cream  or  hght  drab  color.  Magnesia  produces  a  brown 
color,  and  when  present  with  iron  makes  the  bricks  yellow. 

The  color  of  pressed  bricks  is,  of  course,  the  same  as  that  of  com- 
mon bricks  made  from  the  same  clay ;  but  pressed  bricks  are  also 
colored  artificially,  either  by  mixing  together  clays  of  dififerent  chem- 
ical composition,  or  by  mixing  mineral  paints  or  mortar  colors  with 
the  clay  in  the  dry-pan.  Bricks  are  also  sometimes  colored  by  apply- 
ing a  mineral  pigment  to  their  faces  before  burning.  This  latter 
method,  however,  is  not  very  satisfactory.  At  the  present  time  the 
use  of  colored  bricks  is  very  popular,  and  face-bricks  are  made  in  all 
shades  of  red,  pink,  buff,  cream  and  yellow.    Some  of  these  colors 


I  I 

I  I 

I  I 

M.     1  I 

,1   I 


11    3:10  i'H 


2:1  i 


2:6- 


Fig.  163. — Diagram  of  Coursing  for         by  4  by  L'?/^-Inch  Bricks,  3/16-Inch  Joints. 

are  very  effective  when  used  in  an  artistic  manner,  but  the  use  of 
colored  bricks  has  been  much  abused,  and  it  requires  a  fine  sense  of 
color  to  use  them  effectively,  especially  where  two  or  more  shades 
are  used  in  the  same  building. 

335.  SIZES  AND  WEIGHTS  OF  BUILDING  BRICKS.— In 
this  country  there  is  no  legal  standard  for  the  size  of  bricks,  and  the 
dimensions  vary  with  the  maker  and  also  with  the  locality.  In  the 
New  England  States  the  common  bricks  average  about  7^  by  3^ 
by  2^  inches.  In  most  of  the  Western  States  common  bricks  meas- 
ure about  8^  by  4^/3  by  2^  inches,  and  the  thicknesses  of  the  walls 
measure  about  9,  13,  18  and  22  inches  for  thicknesses  of  i,  i^,  2 
and  2^  bricks.    The  sizes  of  all  common  bricks  vary  considerably 


BRICKS— MANUFACTURE. 


327 


in  each  lot,  according  to  the  degree  to  which  the  bricks  are  burnt; 
the  hard  bricks  being  from  yi  to  of  an  inch  smaller  than  the 
salmon  bricks. 

Pressed  bricks  or  face-bricks  are  more  uniform  in  size,  as  most 
of  the  manufacturers  use  the  same  sizes  of  molds.  The  prevail- 
ing size  for  pressed  bricks  is  8^  by  4^^  by  2^  inches.  Pressed 
bricks  are  also  made  ij/  inches  thick  and  12  by  4  by  inches, 
those  of  the  latter  size  being  generally  termed  "Roman  Bricks,'* 
or  "Roman  Tiles." 

Pressed  bricks  should  be  made  of  such  sizes  that  two  headers  and 
a  joint  will  equal  one  stretcher,  and  it  is  also  desirable  that  the 
length  of  a  brick  be  made  equal  to  three  courses  of  bricks  when 
laid.  The  National  Brickmakers'  Association  in  1899  adopted 
8^4  by  4  by  2>4  inches  as  the  standard  size  for  common  bricks,  8^ 


I  J       I      '-'16    i        I       I       I  I 

ni  2:9 1 A  1    ■  r.3r  1    I    I  I 


ni  -^-^^  H  ;    I  1-11 
II  ^'-^r^  I  I 


i[^      lu      ![r:zzDU      i^^^w^  i. 

Fig.  164. — Diagram  for  gj^  by  4  by  i^-Inch  Bricks,  3/16-Inch  Joints. 

by  4  by  2^  for  face-bricks,  8>^  by  4  by  2^^  inches  for  paving 
bricks  and  12  by  4  by  i>4  inches  for  Roman  bricks. 

Figs.  163  and  164  are  diagrams,  reproduced  through  the  courtesy 
of  Gladding,  McBean  &  Co.,  San  Francisco. 

Fig.  163  shows  the  average  coursing  and  length  of  pressed  bricks 
of  dimensions  8^4  by  4  by  2^  inches,  when  laid  with  j^'V-inch  bed 
and  head  mortar  joints. 

Fig.  164  shows  the  same  for  a  ''Roman"  shape  of  dimensions 
834  by  4  by         inches,  laid  with  joints  of  the  same  thickness. 

As  all  bricks  shrink  more  or  less  in  burning,  it  is  generally  neces- 
sary to  assort  even  pressed  bricks  into  piles  of  different  thicknesses 
in  order  to  get  first-class  work. 

The  weight  of  bricks  varies  considerably  with  the  quality  of  the 
clay  from  which  they  are  made,  and  also  of  course  with  their  size. 


328 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


Common  bricks  average  about  4^  pounds  each,  and  pressed  bricks 
vary  from  5  to  5I/2  pounds  each. 

336  REQUISITES  OF  GOOD  BRICKS.— i.  Good  building 
bricks  shoukl  be  sound,  free  from  cracks  and  flaws  and  from  stones 
and  lumps  of  any  kind,  especially  lumps  of  lime. 

2.  To  insure  neat  work,  the  bricks  must  be  uniform  if!  size  and 
the  surfaces  true  and  square  to  each  other,  with  sharp  edges  and 
angles. 

3.  Good  bricks  should  be  quite  hard  and  burned  so  thoroughly 
that  there  is  incipient  vitrification  all  through  the  bricks.  A  sound,' 
well-burned  brick  will  give  out  a  ringing  sound  when  struck  with 
another  brick  or  with  a  trowel.  A  dull  sound  indicates  soft  or 
shaky  bricks.  This  is  a  simple  and  generally  a  sufficient  test  for 
common  bricks,  as  bricks  with  a  good  ring  are  generally  sufficiently 
strong  and  durable  for  any  ordinarv  work. 

4.  A  good  brick  should  not  absorb  more  than  one-teiith  of  its 
weight  of  water.  The  durability  of  brickwork  that  is  e:^posed  to  the 
action  of  water  and  frost  depends  more  ■  upon  the  absorptive 
power  of  the  bricks  than  upon  any  other  condition ;  hence,  other 
conditions  being  the  same,  those  bricks  which  absorb  the  least 
amount  of  water  will  be  the  most  durable  in  outside  walls  and  foun- 
dations. As  a  rule  the  harder  a  brick  is  burned  the  less  water  it  will 
absorb.  "Very  soft,  underburned  bricks  will  absorb  from  25  to  35 
per  cent  of  their  weight  of  water.  Weak,  light  red  ones,  such  as 
are  frequently  used  in  filling  in  the  interior  of  walls,  will  absorb 
from  20  to  25  per  cent,  while  the  best  bricks  will  absorb  only  4  or  5 
per  cent.  A  brick  may  be  called  ''good"  which  will  absorb  not  more 
than  10  per  cent."* 

337.  STRENGTH  OF  BRICKS.— Good  common  bricks,  suit- 
able for  piers  and  heavy  work,  should  not  break  under  a  crushing 
load  of  less  than  4,000  pounds  per  square  inch ;  any  additional 
strength  is  not  of  great  importance,  provided  the  bricks  meet  the 
preceding  requirements.  In  a  wall  the  transverse  strength  is  usually 
of  more  importance  than  the  crushing  strength.  For  an  unusually 
good  common  brick  the  modulus  of  rupture  should  be  not  less  than 
720  pounds  per  square  inch,  or,  in  other  words,  a  brick  8  inches  long, 
4  inches  wide  and  2]/^  inches  thick  should  not  break  under  a  center 
load  of  less  than  1,620  pounds,  the  brick  lying  flatwise  and  having 
a  bearing  at  each  end  of  i  inch  and  a  clear  span  of  6  inches.  A 

*  Ira  O.  Raker,  in  "Masonry  Construction." 


BRICKS— MA  N  UFA  CTURE.  329 

brick  which  is  considered  very  hard  and  first-class  in  every  respect 
should  carry  2,250  pounds  in  the  middle  without  breaking,  and 
bricks  have  been  tested  which  carried  9,700  pounds  before  breaking. 

338.  SAND-LIME  BRICKS.— General  Description.— Ssiud- 
lime  bricks  were  originally  made  of  lime  mortar,  molded  in  brick 
form  and  hardened  by  exposure  to  the  air.  Such  bricks  are  said 
to  have  been  largely  used  in  ancient  times,  and  it  is  claimed  that 
remains  of  such  material  are  now  in  evidence  and  in  a  good  state 
of  preservation.  It  is  know^n  that  thev  were  formerly  used  in 
Europe  in  localities  where  other  materials  were  not  readily  avail- 
able, and  that  they  have  been  used  in  some  localities  in  this  country 
during  the  last  thirty  years.  The  writer  knows  of  several  houses 
in  Haddonfield,  N.  J.,  built  of  such  bricks,  generally  with  exterior 
surfaces  plastered.  One  of  them,  however,  said  to  be  about  twenty 
years  old,  has  not  been  plastered,  and  an  inspection  showed  the 
bricks  to  be  in  an  excellent  state  of  preservation. 

Lime-mortar  bricks  harden  by  the  absorption  of  carbonic  acid 
gas  from  the  air,  which  enters  into  combination  with  the  lime,  form- 
ing carbonate  of  lime.  The  hardening  process  requires  several 
weeks'  exposure  under  cover  and  the  product  has  not  virtues 
sufficient  to  commend  it  where  other  materials  are  available. 

It  was  discovered  in  Germany  about  forty  years  ago  that  lime- 
mortar  bricks  could  be  hardened  in  a  few  hours  under  heat  and 
pressure,  and  it  was  found  later  that  the  chemical  reaction  under 
the  new  process  differs  essentially  from  that  just  described,  and  that 
the  percentage  of  lime  can  be  greatly  reduced. 

The  fundamental  principles  of  sand-lime  brick  manufacture  are 
now  common  property  and  only  the  details  of  manufacture  are 
patentable.  The  commercial  development  of  the  industry  dates  back 
about  twenty  years  in  Europe,  to  about  1888,  and  only  seven  years 
in  this  country,  to  1901.  There  are  now,  in  1908,  over  300  factories 
in  Germany,  one  of  them  with  a  capacity  of  200,000  bricks  per  day. 
There  are  said  to  be  now  over  200  factories  in  operation  in  this 
country. 

The  economic  features  of  the  manufacture  are  such  that  the 
industry  will  doubtless  be  rapidly  extended  and  the  product  come 
into  more  general  use  than  in  the  past. 

The  Process, — Pure  silica  sand,  mixed  with  from  5  per  cent  to  10 
per  cent  of  high  calcium  lime  and  a  certain  proportion  of  water,  is 
molded  under  very  high  pressure  into  the  form  of  bricks.  These 


330 


BUILDING  CONSTRUCTION. 


(Ch.  VII) 


are  piled  loosely  on  cars  holding  about  i,ooo  bricks  each  and  placed 
in  a  steel  cylinder  large  enough  to  hold  from  lo  to  20  cars.  The 
cylinder  is  then  closed,  and  steam  is  turned  in  and  maintained  at  a 
pressure  of  from"  120  to  135  pounds  to  the  square  inch  for  from  8 
to  10  hours,  when  the  cylinder  is  opened  and  the  bricks  removed, 
ready  for  use. 

The  tremendous  pressure,  which  is  said  to  be  100  tons  on  each 
brick,  under  which  the  bricks  are  formed,  causes  great  density  and 
a  bringing  of  the  component  elements  into  close  contact.  The  heat 
in  the  cylinder  dries  the  bricks  and  causes  a  chemical  reaction  be- 
tween the  lime  and  a  portion  of  the  silica,  forming  calcium  silicate, 
an  insoluble  and  perfectly  durable  element,  which  bonds  the  remain- 
ing particles  of  the  sand  together.  The  small  residue  of  uncom- 
bined  lime  combines,  in  the  course  of  time,  either  with  silica  or  with 
carbonic  acid  gas  from  the  air,  until  no  free  lime  remains.  The 
bricks  thus  become  harder  and  stronger  with  age. 

In  regard  to  the  constitution  of  sand-lime  bricks,  Mr.  Edwin  C. 
Eckel,  in  the  chapter  on  "The  Production  of  Lime  and  Sand-lime 
Brick  in  1906,"  in  the  Government  Report  on  "The  Mineral  Re- 
sources of  the  United  States  for  the  Calendar  Year,  1906,"  dated 
1907  and  published  in  1908,  writes  as  follows : 

*Tn  previous  publications  on  the  sand-lime  brick  industry  the 
writer  has  stated  that  conclusive  evidence  had  not  yet  been  pro- 
duced as  to  the  constitution  of  the  binding  medium  of  sand-lime 
brick.  The  advocates  of  the  new  product  not  only  claimed  that  a 
definite  lime  silicate  was  formed  during  processes  of  manufacture, 
but  usually  made  the  additional  claim,  by  implication  at  least,  that 
this  silicate  was  the  same  as  that  which  exists  in  Portland  cement. 
The  fact  was  overlooked  that  purely  chemical  means  could  not  be 
relied  on  to  prove  these  facts,  if  facts  they  were.  Under  these  cir- 
cumstances the  writer,  admitting  his  own  incompetency  to  decide 
the  question,  believed  it  advisable  to  consider  the  matter  unsettled, 
pending  a  decisive  test  by  the  only  means  possible — the  petrographic 
microscope,  used  by  one  of  the  very  few  investigators  intimately 
acquainted  with  the  lime-silicate  series. 

"During  the  past  year  evidence  has  been  submitted  which  seems 
conclusive.  Mr.  Frederick  E.  Wright,  at  the  writer's  request,  ex- 
amined several  specimens  of  commercial  sand-lime  brick  in  the 
geophysical  laboratory  of  the  Carnegie  Institution.  Mr.  Wright 
states  that  the  binding  material  of  these  specimens  is  a  hydrous  lime 


BRICKS— MANUFACTURE. 


331 


silicate  somewhat  akin  to  the  famiHar  minerals  of  the  zeolite  group. 
The  reactions  involved  in  the  formation  of  such  a  hydrous  silicate 
from  lime  and  sand  in  the  presence  of  steam  are  simple  and  well 
known.  It  is  to  be  noted,  however,  that  these  reactions  are  in  no 
way  comparable  to  those  which  take  place  during  the  processes  of 
Portland  cement  manufacture  and  that  the  binding  material  of 
sand-lime  brick  is  very  different  in  composition  and  relationship 
from  Portland  cement  clinker. 

'Tt  may  safely  be  assumed,  then,  that  a  sand-lime  brick  as  mar- 
keted consists  of  (i)  sand  grains  held  together  by  a  network  of  (2) 
hydrous  lime  silicate,  with  probably  (if  a  magnesian  lime  were 
used)  some  allied  magnesian  silicate,  and  (3)  lime  hydrate  or  a 
mixture  of  lime  and  magnesia  hydrates.  These  three  elements  will 
always  be  present,  and  the  structural  value  of  the  brick  will  depend 
in  large  part  on  the  relative  percentages  in  which  the  sand  and  the 
hydrates  occur." 

Quality. — The  quality  of  the  product  depends  mainly  upon  the 
selection  and  treatment  of  the  sand  and  the  lime.  Pure  silica  sands, 
containing  a  large  percentage  of  fine  grains  passing  through  screens 
of  from  80  to  150  mesh,  are  preferable.  Clay  or  kaolin  are  danger- 
ous elements  and  should  not  be  present  in.  quantities  of  more  than  5 
per  cent.  The  lime  should  be,  preferably,  high  calcium  lime,  the 
magnesium  silicates  formed  by  impure  limes  not  being  as  strong  as 
calcium  silicates.  Some  manufacturers  use  ready-hydrated  lime, 
others  hydrate  the  lime  themselves,  before  mixing  it  with  the  sand, 
and  others  grind  the  quicklime,  mix  it  with  the  sand  and  slaken  it 
in  the  sand. 

The  other  most  important  element  affecting  quality  is  the  press. 
After  pressing  and  before  steaming,  the  bricks  are  very  fragile  and 
the  press  should  be  such  that  they  are  subjected  to  no  shaking  nor 
friction  after  the  pressure  is  removed  from  the  mold.  Vertical 
clay  brick-presses  have  been  commonly  used,  but  do  not  appear  to 
be  well  adapted  to  the  purpose.  The  rotary  table-presses  seem  to  be 
most  successful. 

Tests. — If  the  sand  is  reasonably  clean  and  pure,  and  the  lime 
finely  divided ;  and  if  the  bricks  are  sound  and  have  a  good  metallic 
ring,  they  will  stand  weather  exposure  perfectly. 

If  a  brick  stands  in  still  water  for  an  hour  and  the  moisture  rises 
more  than  ^  an  inch,  it  is  not  a  first-class  brick ;  if  the  moisture 
rises  2  inches,  its  use  for  facings  is  questionable ;  if  the  moisture 


332 


BUILDING  CONSTRUCTION.         (Ch.  VII) 


rises  3  inches,  it  should  not  be  used  on  outside  work  of  any  impor- 
tance. 

Authentic  tests*  have  been  made  for  crushing,  fire,  frost  and 
acid-resistance  and  for  absorption,  from  which  it  may  be  concluded 
that  under  proper  conditions  of  manufacture  sand-lime  bricks  are 
produced  having  the  following  physical  characteristics :  Crushing 
strength,  average,  between  2,500  and  3,000  pounds  per  square  inch, 
although  some  specimens  in  tests  have  shown  over  5,000  pounds  per 
square  inch ;  modulus  of  rupture,  average  about  450  pounds  per 
square  inch;  fire-resistance,  but  little  inferior  to  that  of  fire-brick; 
frost-resistance,  perfect ;  acid-resistance,  very  superior ;  absorption, 
from  8  per  cent  to  10  per  cent  in  48  hours;  average  for  complete 
saturation,  15  per  cent;  reduction  of  compressive  strength  by  satu- 
ration for  absorption  test,  average  33  per  cent. 

The  New  York  laws  require  for  the  absorption  test,  an  average 
not  exceeding  15  per  cent,  and  no  result  over  20  per  cent;  for  the 
modulus  of  rupture  test,  an  average  of  450  pounds  per  square  inch, 
with  no  result  below  350;  for  the  compression  test,  an  average  of 
3,000  pounds  per  square  inch,  with  no  result  less  than  2,500  pounds ; 
and  for  the  reduction  of  compressive  strength  after  saturation,  a 
loss  of  not  more  than  one-third. 

The  bricks  are  square,  straight  and  uniform  in  size  and  homo- 
geneous in  composition  and  density.  They  cleave  accurately  under 
the  stroke  of  the  trowel  and  present  a  weather  surface  with  the 
good  qualities  of  stone.  They  can  be  cut,  carved  or  sand-blasted, 
are  easily  washed  clean  and  show  no  efflorescence.  These  claims 
are  well  established  for  properly  manufactured  sand-lime  bricks. 
It  should  be  further  stated  that  common  bricks  and  facings  are 
made  in  the  same  press,  the  only  difference  being  in  the  selection 
of  the  materials  and  in  the  handling  of  the  raw  bricks.  It  is  there- 
fore claimed  that  a  rational  and  homogeneous  exterior  wall  struc- 
ture is  possible,  since  backings  and  facings  may  be  built  and  bonded 
in  even  courses,  with  Flemish  or  other  ornamental  bonds. 

Many  factories,  however,' are  producing  inferior  bricks  and  care 
should  be  taken  in  their  selection. 

Colors  in  Sand-lime  Bricks. — The  natural  color  is  pearl  gray, 
varying  in  warmth  with  the  composition  of  the  sand.  Permanent 

*  See  also  "Tests  Upon  Sand-lime  Bricks,"  made  by  Professor  Ira  H.  Woolson,  in 
November,  1905,  at  the  Testing  Laboratory,  Columbia  University,  New  York,  for  The 
National  Association  of  Manufacturers  of  Sand-lime  Products. 


BRICKS-MANUFACTURE. 


333 


colors  are  produced  by  introducing  mineral  oxides  with  the  raw- 
materials  in  quantities  varying  according  to  the  intensity  of  color 
fiesired ;  but  as  the  oxides  are  foreign  materials  in  the  bricks,  they 
affect  the  quality  of  the  latter  in  proportion  to  the  quantity  used- 
Production  of  Sand-liuic  Bricks. — In  the  year  1906  the  product 

TABLE  XXV. 

Production  of  Sand-lime  Bricks  in  the  United  States  in: 

1906,  BY  States. 


state 


Alabama,  Kentucky. 
Mississipri  and  Ten- 


nessee  

Arkansas,  Kansas, 
Minnesota,Nebraska, 
South  Dakota  and 
Texas  

California  

Colorado  and  Idaho. . . 

Delaware,  Maryland 
and  Virginia  

Florida.'.  

Georgia  

Illinois  and  Wisconsin 

Indiana  

Iowa  

Michigan  

New  Jersey  

New  York  

North  Carolina  

Ohio  

Pennsylvania  

Other  States  6  


Total  

Average  value  per  M 


Num- 
ber of 
oper- 
ating 
firms 
re- 
port- 
ing 


Common 
bricks 


87 


Quan- 
tity 
(thou- 
sands) 


Value 


14,877 
4,837 
5G9 

9,403 

11,678 
5,139 
8,150 

17,077 
3,921 

27,281 
6,.52() 

21,288 
3,147 
1,232 
6,673 


148,669 


$51,079 


'96,128 
"  38,789 
6,043 

61.719 
83,306 
37,701 
49,150 
84,361 
28,271 

162,879 
49,143 

169,257 
22,225 
7,049 
50,211 


997,311 
6.71 


Front 
bricks 


QuaTi- 

tity 
(thou- 
sands) 


1,276 


1.897 
1,900 
2,191 

(a) 

(a) 

ia) 
690 
326 

(a) 

1,796 


1,910 

(a) 

(a) 

978 
2,718 


15,682 


Value 


Fancy 
bricks 


Quan- 
tity 
(thou- 
sands) 


$11,94^ 


17,982  ((f) 

22,400'  

22,743   


(-0 

(n) 

in) 

6,060 

2,474 

(a) 

12,022 


22,064 
(a) 
(a) 

12,710 
32,963 


163,345 
10.42 


Value 


(a) 


in) 
(a) 
(a) 


121 


121 


(ft) 
ia) 
(a) 


$3,473 


3,473 
28.70 


Block.^ 
value 


(^0 


Totar 
valuer 


(a) 
'ia) 


$5,876  ! 


$63,02® 


114,360> 
61,189 
31,464 

67,U9' 
89,306;. 
40,701 
55,210. 
86,880- 
38,255:. 

174.921 
50,14X: 

191,321 
32,975. 
10,184 
62,921 


5,876  1,170,00* 


a  Included  in  other  States. 

b  Includes  all  products  made  by  less  than  three  producers  in  one  State,  to  prevent  dis- 
closing individual  operations. 

c  The  total  of  other  States  is  distributed  among  the  States  to  which  it  belongs  im 
order  that  they  may  be  fully  represented  in  the  totals. 

Value  of  production  of  sand-lime  bricks  in  the  United  States,  igo^-rgod. 


Year 

Number 
of  plants 

Value  of 
product 

1903  

16 

$155,040* 
46:3, 128-. 
972,064 
1,170,005. 

1904  

57 

1905  

84 

1906  

87 

of  the  sand-lime  brick  industry  was  valued  at  $1,170,005,  an  increase 
of  20  per  cent  over  the  value,  $972,064,  in  1905.    During  1906  the 


334 


BUILDING  CONSTRUCTION.     '   (Ch.  VII)' 


value  of  the  common  building  bricks  made  by  this  process  averaged 
$6.71  per  thousand,  as  against  $6.59  in  1905.  The  front-bricks 
averaged  $10.42  per  thousand,  as  against  the  1905  average  of 
$11.02.  Almost  90  per  cent  of  the  entire  sand-lime  product  is 
marketed  as  common  bricks,  a  result  which  could  hardly  have  been 
anticipated  when  these  bricks  were  first  introduced  into  this  country. 

Detailed  statistics  for  1906  are  presented  in  Table  XXV. 

339.  CEMENT  BRICKS. — Cement  bricks  are  on  the  market  in 
many  places,  and  are  used  generally  for  facing  purposes.  Their 
characteristics  are  similar  to  those  of  concrete  hollow  blocks,  and 
observations  made  of  one  product  are  generally  true  of  the  other. 
They  are  manufactured  by  machine,  by  hand  or  by  power  presses, 
and  the  following  general  principles  should  be  observed. 

Other  conditions  being  equal,  wet  concrete  mixtures  tend  to 
density,  non-absorption  and  fineness  of  face. 

Concrete  attains  its  normal  strength  with  its  seasoning.  Cement 
bricks  should  not  be  used  earlier  than  two  weeks,  and  should  not 
carry  considerable  loads  earlier  than  one  month  after  the  date  of 
manufacture.  Lean  mixtures,  however,  require  more  time  than 
rich  mixtures. 

Cement,  sand  and  stone  mixtures  are  stronger,  denser  and  less 
absorbent,  and  require  less  cement  than  cement  and  sand  mix- 
tures. One  part  of  cement  to  4  of  sand,  or  i  part  of  cement  to  3 
of  sand  and  3  of  aggregates  from  io  lA  an  inch  in  size,  are 
given  as  minimum  proportions  of  cement  for  cement  bricks. 

Much  depends  upon  the  character  of  the  sand.  It  should  contain 
both  fine  and  coarse  grains  and  should  be  clean  and  sharp. 

By  the  selection  of  the  color,  shape  and  size  of  the  aggregates 
and  by  the  subsequent  treatment,  either  by  washing  with  acid  or 
with  water  and  stifif  brushes,  the  faces  of  the  bricks  may  be  given 
various  textures  and  colors.  Various  colors,  also,  are  used  in  the 
cement. 

Good  cement  bricks  should  stand  the  following  minimum  tests 

Average  minimum  ultimate  compressive  strength,  at  28  days, 
1,000  pounds  per  square  inch. 

Average  modulus  of  rupture  at  same  age,  not  less  than  150 
pounds  per  square  inch. 

Absorption  not  over  15  per  cent. 

*  "Standard  Specifications  for  Concrete  Hollow  Blocks,"  prepared  by  E.  S.  Larned, 

C.  E.,  for  National  Association  of  Cement  Users 


BRICKWORK  IN  GENERAL. 


335 


Cement  bricks  for  any  particular  building  should  be  carefully 
investigated  and  rigidly  inspected  for  uniformity  of  quality. 

For  further  discussions  of  concrete  mixtures,  concrete  blocks, 
etc.,  see  Chapter  X. 

2.    BRICKWORK  IN  GENERAL. 

340.  In  order  to  build  any  kind^of  brick  structure  so  as  to  make 
a  strong  and  durable  piece  of  work,  it  is  necessary  to  have  a  bed 
of  some  kind  of  mortar  between  the  bricks.  Brickwork,  there- 
fore, consists  of  both  bricks  and  mortar,  and  the  strength  and  dur- 
ability of  any  piece  of  work  depend  upon  the  quality  of  the  bricks, 
the  quality  of  the  mortar,  the  way  in  which  the  bricks  are  laid  and 
bonded  and  whether  or  not  they  are  laid  wet  or  dry. 

The  strength  and  stability  of  a  wall,  arch  or  pier  also  depend 
upon  its  dimensions  and  the  load  it  supports  ;  but  for  the  quality 
of  the  brickwork,  only  the  above  items  need  be  considered. 

The  kinds  and  qualities  of  mortars  used  for  laying  brickwork  are 
described  in  Chapter  IV.  The  majority  of  the  brick  buildings  in 
this  country  have  been  built  with  common  white  lime  mortar,  to 
which  natural  ' or  Portland  cement  has  been  added.  For  brickwork 
below  ground  either  hydraulic  lime  or  cement  mortar  should  be 
used.    (See  Articles  153,  164  and  200.) 

The  function  of  the  mortar  in  brickwork  is  threefold,  viz. : 

1.  To  keep  out  wet  and  changes  in  temperature  by  filling  al! 
crevices. 

2.  To  unite  the  whole  into  one  mass. 

3.  To  form  a  cushion  to  take  up  any  inequalities  in  the  brick?^ 
and  to  distribute  the  pressure  evenly. 

The  first  object  is  best  attained  by  grouting,  or  thoroughlv  ''flush- 
ing" the  work ;  the  second  depends  largely  upon  the  strength  of  the 
mortar,  and  the  third  is  effected  principally  by  the  thickness  of  the 
joints. 

341.  THICKNESS  OF  MORTAR  JOINTS.— Common  bricks 
should  be  laid  in  a  bed  of  mortar  at  least       and  not  more  than 

of  an  inch  thick,  and  every  joint  and  space  in  the  wall  not. 
occupied  by  other  materials  should  be  filled  with  mortar.  The  best 
method  of  specifying  the  thickness  of  joints  is  by  the  height  of 
eight  courses  of  bricks  measured  in  the  wall.  This  height  should 
not  exceed  by  more  than  2  inches  the  height  of  eight  courses  of 
the  same  bricks  laid  dry. 


33^ 


BUILDING  CONSTRUCTION.         (Ch.  VII) 


As  common  bricks  are  usually  quite  rough  and  uneven,  it  is  not 
always  easy  to  determine  the  thickness  of  a  single  joint;  but  the 
variation  from  the  specification  in  any  eight  courses  that  may  be 
selected  should  be  very  slight.  It  is  not  uncommon  to  see  joints 
^  of  an  inch  thick  in  common  brickwork,  especially  where  the 
Avork  is  not  superintended.  ^ 

Pressed  bricks,  being  usually  quite  true  and  smooth,  can  be  laid 
with  ^-inch  joints,  and  they  are  often  so  specified.  A  yVi^ch  thick- 
ness is  probably  stronger,  however,  as  it  permits  a  more  thorough 
filling  of  the  joint. 

It  is  impossible  to  completely  fill  or  -f^-inch  joints  with 
mortar.  Numerous  small  holes  admit  driving  rains  in  streams. 
Efflorescence  can  in  many  cases  be  traced  to  holes  in  the  facing. 

\^ery  little  first-class  work  is  now  done  with  fine  joints,  the 
tendency  being  toward  wall  surfaces  with  character  and  texture. 
The  joints'  should  be  thick  enough  to  bring  the  facings  to  an  even 
bed  with  the  backings,  and  to  allow  them  to  be  bonded  with  the 
headers,  and  they  may  be  from  j4  of  an  inch  to  i  inch  in  thickness. 
They  are  frequently  recessed  from  j/^  to  ^  of  an  inch.  The  hori- 
zontal joints  may  be  recessed  with  the  vertical  joints  flush  ;  or  the 
horizontal  joints  may  be  thick  and  the  vertical  joints  thin. 

342.  LAYING  BRICKS.— A.  C-ommon  Bricks.— Tht  best 
way  to  build  a  brick  wall  is,  first,  to  lay  the  two  outside  courses 
by  spreading  the  mortar  with  a  trowel  along  the  outer  edge  of 
the  last  course  of  bricks,  to  form  a  bed  for  the  bricks  to  be  laid, 
scraping  a  dab  of  mortar  against  the  outer  vertical  angle  of  the 
last  brick  laid ;  and  then  to  press  the  bricks  to  be  laid  into  their 
places  with  a  sliding  motion,  forcing  the  mortar  to  completely 
fill  each  joint.  • 

Having  continued  the  two  outer  courses  of  bricks  to  an  angle  or 
opening,  the  space  between  the  courses  is  filled  with  a  thick  bed 
of  soft  mortar  and  the  bricks  pressed  into  this  mortar  with  a 
downward  diagonal  motion,  so  as  to  press  the  mortar  up  into 
the  joints.  This  method  of  laying  is  called  "shoving."  If  the 
mortar  is  not  too  stiff,  and  is  thrown  into  the  wall  with  some  force, 
it  will  completely  fill  the  upper  part  of  the  joints,  which  are  not 
filled  by  the  shoving  process.  A  brick  wall  laid  up  in  this  way  is 
very  strong  and  difficult  to  break  down.    This  class  of  work  is 


BRICKWORK 


IN  GENERAL. 


337 


commonly  called  ''shoved  work."  It  is  done  only  under  constant 
supervision  and  is  more  expensive  than  ordinary  brickwork.  « 

A  very  common  method  of  laying  the  inside  bricks  in  a  wall  is 
to  spread  a  bed  of  mortar  and  on  this  lay  the  dry  bricks.  If  the 
bricks  are  laid  with  open  joints  and  thoroughly  slushed  up  it  makes 
very  good  work;  but  unless  the  men  are  carefully  watched  the  joints 
are  not  filled  with  mortar  and  the  wall  is  not  as  strong  as  when 
the  bricks  are  shoved. 

Grouting. — Another  method  of  laying  the  inside  bricks  is  to  lay 
them  dry  on  a  bed  of  mortar,  as  described  above,  and  then  to  fill 
all  the  joints  full  with  a  very  thin  mortar.  This  is  called  "grout- 
ing," and,  while  it  is  condemned  by  many  writers,  it  is  contended 
by  persons  having  large  experience  in  building  that  masonry  care- 
fully grouted,  when  the  temperature  is  not  lower  than  40  degrees 
Fahr.,  will  give  the  most  efficient  result ;  and  the  author  knows  from 


Fig.   165. — Struck  Joint  Fig.  i66. — Struck  Joint 

with  Drip.  without  Drip. 

actual  experience  that  when  properly  done  it  makes  very  strong 
work.  Many  of  the  largest  buildings  of  New  York  City  have 
grouted  walls.  The  iMersey  Docks  and  Warehouses  at  Liverpool, 
England,  one  of  the  greatest  masonry  works  in  the  world,  were 
grouted  throughout.  No  more  water  than  is  necessary  to  make 
the  mortar  fill  all  the  joints  should  be  used,  and  grouting  should 
not  be  used  in  cold  or  freezing  weather.  Grouting  is  especially 
valuable  when  very  porous  bricks  are  used.  (See  Article  206, 
"Grout,"  in  Chapter  IV.) 

Striking  the  Joints. — For  inside  walls  that  are  to  be  plastered  the 
mortar  projecting  from  the  joints  is  merely  cut  off  with  the  trowel 
flush  with  the  face  of  the  walls.  For  outside  walls  and  inside  walls, 
where  the  bricks  are  left  exposed,  the  joints  should  be  "struck'' 
as  in  Fig.  165.    This  is  done  with  the  point  of  the  trowel,  by  hold- 


338 


BUILDING  CONSTRUCTION.         (Ch.  VII) 


ing  it  obliquely.  Fig.  i66  is  the  easiest  joint  to  make,  and  is  the 
one  ^generally  made  unless  that  shown  in  Fig.  165  is  insisted  on. 
For  inside  work  it  makes  no  particular  difference  which  joint  is 
used,  but  for  outside  work  Fig.  165  is  much  more  durable,  as  the 
water  will  not  lodge  in  it  and  soak  into  the  mortar,  as  will  be  the 
case  when  it  is  made  as  in  Fig.  166. 

When  "struck  joints"  are  desired  they  should  always  be  specified, 
otherwise  the  brick-mason  may  claim  that  he  is  not  obliged  to  strike 
them. 

B.  Face-bricks. —  (See  also  Article  341.)  Face-bricks  are 
usually  laid  in  mortar  made  of  lime  putty  and  very  fine  sand,  often 
colored  with  a  mineral  pigment.  (See  also  Articles  150,  216,  217 
and  218.)  The  joints  should  not  exceed  Vie  of  an  inch,  except 
in  cases  where  a  horizontal  effect  is  desired,  when  the  horizontal 
joints  are  made  ^  of  an  inch  and  the  vertical  joints  as  narrow  as 
possible.  For  very  fine  work  the  joints  are  sometimes  kept  down 
to  of  an  inch.  The  joints  should  be  carefully  filled  with  mortar 
and  either  ruled  at  once  with  a  small  jointer  or  else  raked  out  and 
left  for  pointing.  In  very  particular  work  a  straight-edge  is  held 
under  the  joint  and  the  jointer  drawn  along  the  top  of  it,  thus 
making  a  perfectly  straight  joint.  This  is  called  ''ruled  work."  In 
laying  the  soffits  of  arches  and  vaults  with  face-bricks,  the  joints 
cannot  be  finished  until  the  centers  are  removed  ;  the  joints  should 
therefore  be  not  quite  filled  with  mortar,  and  should  be  raked  out 
and  pointed  after  the  centers  are  removed. 

Many  makes  of  pressed  bricks  and  some  hand-made  bricks  have 
one  or  more  depressions  in  the  larger  surfaces  to  give  better  keys  to 
the  mortar.  When  the  depressions  are  on  one  side  of  a  brick 
only,  that  side  should  be  uppermost. 

When  building  with  face-bricks,  a  piece  of  brickwork  at  least  2 
feet  6  inches  long  should  be  built  up,  as  a  sample  piece,  in  an  out- 
of-the-way  place  as  soon  as  the  first  lot  of  bricks  is  delivered ;  and 
all  stone  or  terra-cotta  work  should  be  made  to  conform  absolutely 
to  this  brickwork. 

Sorting. — Pressed  bricks,  even  from  the  same  kiln,  generally 
vary  in  size  and  shade,  the  darker  bricks  being  often 
inch  thinner  than  the  lighter  bricks  and  also  shorter.    If,  therefore, 
a  perfectly  uniform  color  is  desired  the  bricks  must  be  sorted  into 


BRICKWORK  IN  GENERAL. 


339 


piles,  so  that  each  lot  will  be  of  the  same  shade,  and  each  shade  laid 
in  the  building  by  itself.  The  changes  between  the  different  shades 
should  occur,  where  possible,  at  string-courses  or  at  angles  in  the 
building.  Many  architects,  however,  consider  that  handsomer  and 
brighter  walls  are  secured  by  mixing  the  different  shades,  so  that 
hardly  two  bricks  of  exactly  the.  same  shade  come  together.  If 
the  mixing  is  well  done  the  general  tone  of  a  wall  at  a  distance 
will  be  uniform.  With  colored  bricks  this  haphazard  method 
undoubtedly  gives  the  most  artistic  and  sparkling  effects. 

Circular  Work. — For  circular  walls,  faced  with  pressed  bricks, 
the  latter  should  be  made  of  the  same,  or  of  very  nearly  the  same, 
curvature  as  that  of  the  wall.  ]\Iany  manufacturers  of  pressed  bricks 
carry  circle  bricks  of  different  curvatures  in  stock,  and  bricks  of 
any  curvature  can  be  made  to  order. 

When  circle  bricks  cannot  be  obtained,  straight  bricks  may  be 
used  for  curvatures  with  a  radius  of  12  feet  or  over,  and  for 
shorter  radii  half  bricks  or  headers  should  be  used. 

343.  WETTING  BRICKS.— Mortar,  unless  very  thin,  will  not 
adhere  to  dry,  porous  bricks,  because  they  rob  the  mortar  of  its 
moisture,  preventing  its  proper  setting.  On  this  account  bricks 
should  never  be  laid  dry,  except  in  freezing  weather;  and  in  hot, 
dry  weather  it  is  impossible  to  get  the  bricks  too  wet.  When  using 
very  porous  bricks  the  wetting  of  them  is  of  more  consequence  in 
obtaining  a  strong  wall  than  any  detail  of  the  operation.  As  wetting 
the  bricks  greatly  increases  their  weight  and  consequently  the  labor 
of  handling  them,  besides  making  it  harder  on  the  hands,  masons 
do  not  like  to  wet  them  unless  they  are  obliged  to,  and  it  should 

,  always  be  specified  and  insisted  upon  by  the  superintendent,  except 
in  freezing  weather. 

Pressed  bricks  cannot  very  well  be  laid  dry,  and  the  masons 
generally  wet  them  for  their  own  convenience ;  but  they  will  often 
tell  all  sorts  of  stories  to  escape  wetting  the  common  bricks. 

344.  LAYING  BRICKS  IN  FREEZING  WEATHER.— 
Brickwork  in  lime  mortar  should  not  be  laid  in  freezing  weather. 
If  the  temperature  is  below  40  degrees  Fahr.  and  liable  to  fall  below 
32  degrees  at  night,  salt  should  be  mixed  with  the  mortar,  the  bricks 
heated  before  laying  and  the  top  of  the  wall  covered  with  boards 
and  straw  at  night.    If  the  mortar  in  any  part  becomes  frozen,  the 


340 


BUILDING  CONSTRUCTION.         (Ch.  VII) 


courses  in  that  part  should  be  removed  and  cleaned  before  they  are 
used  again. 

Cement  mortar  is  not  injured  by  frost  after  the  first  set  has  taken 
place.  It  may  be  used  in  freezing  weather  if  precautions  are  taken 
by  heating  the  materials,  by  protecting  the  walls  or  by  the  use  of 
salt,  to  prevent  freezing  before  this  set  has  taken  place;  otherwise 
a  sudden  thaw  is  liable  to  soften  the  mortar  and  cause  settlement. 
But  it  is  not  considered  good  practice  to  attempt  to  lay  bricks  in 
temperatures  below  from  17  degrees  to  23  degrees  Fahr.  unless  the 
walls  are  in  warmed  enclosures. 

Lime  in  the  mortar  retards  the  setting,  and  mixing  the  mortar 
with  hot  water  hastens  the  setting  and  keeps  the  walls  warm  longer. 
Salt  in  amount  from  2  per  cent  to  8  per  cent  of  the  water  by  weight 
prevents  frost,  but  is  objected  to  by  many  on  account  of  a  resulting 
tendency  to  efflorescence.  Higher  percentages  retard  setting  and 
reduce  the  strength  at  short  periods.  In  any  case  the  bricks  should 
not  be  freezing  cold  nor  wet,  and  they  must  be  clean. 

For  the  efifect  of  freezing  on  mortar  see  Articles  213  and  214. 

345.  PROTECTION  FROM  STORMS.— Moisture  without 
frost  does  not  injure  the  strength  of  brickwork,  but  if  rain  strikes 
the  top  of  a  wall  it  will  wash  the  mortar  out  of  the  joints  and  stain 
the  face  of  the  wall. 

The  excessive  wetting  of  walls  is  also  injurious,  as  it  takes  a  long 
time  for  them  to  dry  out,  and  they  are  likely  never  to  dry  to  a  uni- 
form color.  For  this  reason  the  tops  of  the  walls  should  always 
be  protected  at  night,  or,  when  leaving  ofif  work,  by  boards  placed 
so  as  to  shed  the  water. 

346.  ORNAMENTAL  BRICKWORK.— American  practice  in 
the  design  of  ornamental  brickwork  has  been  derived  chiefly  from 
examples  in  England  and  northern  Italy,  and  it  is  well  to  note  that 
the  long  continued  cold  weather  in  our  northern  localities  demands 
a  treatment  of  such  work  very  different  from  the  practice  in  those 
countries. 

The  upper  surfaces  of  copings  and  brick  projections  are  the 
sources  of  serious  danger  to  the  continued  good  appearance  and  to 
the  permanency  of  the  walls  in  which  they  occur,  unless  protected 
by  overhanging  coverings  with  drips.  Through  the  action  of  the 
frost  the  mortar  in  the  exposed  joints  finally  loses  its  hold  upon  the 
bricks  and  permits  moisture  to  follow  the  joints  to  the  interior  of 
the  walls.    Thence  the  water  is  likely  to  percolate  to  lower  levels 


BRICKWORK  IN  GENERAL. 


341 


and  to  the  outside  surfaces,  depositing  the  chemicals  dissolved  in  its 
path  upon  the  faces  of  the  walls  in  stains  or  efflorescence,  decom- 
posing the  mortar  in  the  joints  and  ultimately  destroying  the  walls. 

The  ornamental  effects  to  be  obtained  by  the  varied  uses  of  bricks 
are  exceedingly  numerous.  First,  there  are  the  constructive  fea- 
tures, such  as  arches,  impost  courses,  pilasters,  belt-courses  and 
string-courses,  cornices  and  panels ;  then  there  is  a  large  field  for 
design  in  surface  ornament,  by  the  use  of  bricks  of  different  hues, 
tints  or  shades,  laid  so  as  to  form  patterns. 

For  the  constructive  features  both  plain  and  molded  bricks  may 
be  used,  although  only  very  plain  effects  can  be  produced  with 
plain  bricks  alone. 

In  nearly  all  of  our  large  cities,  and  especially  in  those  near  which 


Fig.  167. — Brick  Belt-course  Fig.  168. — Brick  Belt-courses, 

with  Wash. 


pressed  bricks  are  manufactured,  a  great  variety  of  molded  bricks 
can  be  obtained,  by  means  of  which  it  is  possible  to  construct  almost 
any  moldings,  belt-courses,  etc.,  that  may  be  desired. 

Belt-courses  and  cornices,  and  in  fact  any  details  of  molded  work 
built  of  bricks,  are  much  cheaper  than  the  same  moldings  cut  in 
stone. 

In  designing  brick  details  the  projections  should  be  kept  small. 

The  tops  of  the  belt-courses  should  have  washes  on  the  top  sur- 
face, as  shown  in  Fig.  167. 

The  top  course,  W,  should  be  laid  with  stretchers*  when  the  pro- 
jection is  not  over  3  inches,  in  order  to  reduce  the  number  of  end 
joints;  and  the  bricks  should  also  be  laid  in  cement  mortar,  so  that 
that  which  is  in  the  end  joints  will  not  be  washed  out. 

If  IV  is  2L  stretcher  course  at  least  every  other  brick  in  the  course 
below  should  be  a  header'. 

If  bevelled  bricks  cannot  be  obtained  for  the  top  courses,  and  if 


342 


BUILDING  CONSTRUCTION. 


(Ch.  VII) 


plain  bricks  must  be  used,  the  upper  surface  should  be  protected 
by  sheet-lead  built  into  the  second  joint  above  it,  as  shown  in  Fig. 
i68  A;  or  the  top  of  the  bricks  may  be  plastered  with  Portland 
cement,  as  shown  in  Fig.  i68  5.*  Unless  some  such  precautions 
are  taken  to  protect  the  tops  of  the  projecting  bricks  from  excessive 
moisture,  the  rain-water  will  after  a  while  soften  the  mortar  in 
the  joints,  P,  and  penetrate  the  wall.  The  end  joints  in  the  belt- 
courses  are  always  liable  to  be  washed  out. 

Belt-courses  and  cornices  should  always  be  well  tied  to  the  walls 
by  using  plenty  of  headers  or  iron  ties.  The  tops  of  the  walls  should 
also  be  well  anchored  to  the  rafters  or  ceiling  joists  by  iron  anchors, 
as  the  projection  of  a  cornice  tends  to  throw  a  wall  outward. 

In  using  molded  bricks  in  string-courses  and  cornices,  it  is  more 
economical  to  use  bricks  that  can  be  laid  at  stretchers,  as  it  takes 


a  smaller  number  of  stretchers  than  of  headers  to  fill  given  lengths, 
and  the  cost  is  the  same. 

One  of  the  greatest  objections  to  brick  moldings  is  the  difficulty 
in  getting  them  perfectly  straight  and  true.  Nearly  all  molded 
bricks  become  more  or  less  distorted  in  molding  and  burning,  so 
that  when  laid  the  abutting  ends  do  not  match  evenly,  and  mold- 
ings present  an  appearance  like  that  shown  in  Fig.  169. 

Some  makes  of  bricks,  however,  are  quite  free  from  these  defects, 
and  before  selecting  molded  bricks  to  be  used  in  this  way  the  archi- 
tect should  endeavor  to  ascertain  what  makes  give  the  truest  and 
most  perfect  work. 

By  being  very  careful  in  laying  the  bricks  so  as  to  average  the 
defects,  and  by  ruling  the  joints,  the  effects  of  the  distortion  may  be 
largely  overcome.  Distortion  is  more  apt  to  show  with  stretchers 
than  with  headers. 


347.    BRICK  CORNICES.— Brick  bed-molds  for  wood  or  iron 


Fig.   169. — Molded  Brick  Course,  Showing  Distortion. 


*  A  temporary  expedient,  which  must  be  renewed  from  time  to  time. 


BRICKWORK  IN  GENERAL. 


343 


ig.  172.— Simple  ^ji^c^'j^CoJ-nice  with  Copper  Fig.  173.— Design  of  Molded  Brick  Cornice. 


344 


BUILDING  CONSTRUCTION. 


(Cii.  VII) 


cornices  may  be  designed  in  wide  variety  and  with  excellent  effect. 
Whole  cornices  may  be  designed  in  brick,  although  only  a  com- 
paratively slight  projection  is  practicable,  and  metal  or  terra-cotta 
coverings  with  efficient  overhanging  drips  are  essential. 


Fig.  175. — Design  for  Molded  Brick  Cornice 


has  used 


Fig. 


76. — Design  for  Molded 
Brick  Cornice. 


•Design  for  Molded  Brick  Cornice. 

Figs.  170  and  171,  taken 
from  The  Brickhuilder,  are 
suggestions  for  molded  brick 
cornices  for  three  and  four- 
story  buildings.  Fig.  172 
shows  a  section  of  a  simple 
brick  cornice  that  the  author 
on  brick  churches  having 
pitched  roofs. 

All  brick  walls  or  cornices  should  be 
capped  by  projecting  copings  of  metal, 
terra-cotta  or  stone,  provided  with  a  hol- 
low drip  to  throw  off  the  water. 

For  brick  cornices  a  copper  or  galva- 
nized-iron  crown-mold,  such  as  is  shown 
in  Fig.  170,  is  very  appropriate.  The 
metal  should  be  carried  over  the  top  of 
the  wall,  if  a  parapet,  and  down  5  inches 
at  the  back. 


BRICKWORK  IN  GENERAL. 


345 


Figs.  173,  174,  175  and  176  show  additional  designs  for  brick 
cornices,  reproduced  through  the  courtesy  of  the  Eastern  Hydrau- 
lic-press Brick  Company,  Philadelphia,  from  ''Suggestions  in  Brick- 
work." Figs.  173  and  175  show  overhanging  eaves  which  may  or 
may  not  be  used.  The  height  of  the  brick  cornice  in  Fig.  173  is 
16  inches  and  the  projection  13  inches;  in  Fig.  174  the  height  is 
24  inches  and  the  projection  14  inches;  in  Fig.  175  the  height  is 
42  inches  and  the  projection  14  inches ;  and  in  Fig.  176  the  height  is 
12  inches  and  the  projection  7  inches. 


Fig-  177- — Brick  Cornice  Modelled  After  Cornice  of  Baptistry  of  San  Stefano,  Bologna, 

Italy. 

Fig.  177  is  a  design  modelled  closely  after  the  cornice  of  the  Bap- 
tistry of  San  Stefano,  Bologna,  Italy. 

If  the  walls  terminate  as  shown  in  Fig.  171  the  upper  courses 
should  be  laid  in  cement  mortar  and  the  tops  well  plastered  with 
Portland  cement  at  the  same  time  the  bricks  are  laid.  This  will 
protect  the  walls  for  several  years,  but  is  not  as  lasting  as  terra- 
cotta or  metal. 

348.    SURFACE   PATTERNS.— Surface  patterns,  or  diaper 


346 


BUILDING  CONSTRUCTION.        (Cii.  VII) 


work,  are  very  common  in  brick  buildings  in  Europe,  and  they  have 
been  introduced  to  a  considerable  extent  in  this  country. 

Their  chief  object  is  to  give  variety  to  a  plain  wall  space.  When 
used  in  exterior  walls  they  should  not  be  so  marked  as  to  make  the 


Fig.   178. — Simple  Brick  Diaper  Pattern  for  Frieze. 


pattern  insistent  and  thus  interfere  with  other  features  of  the 
building. 

Sorting  the  bricks  into  light  and  dark  shades,  or  varying  the 
color  of  the  mortar  in  which  the  pattern  is  laid,  is  usually  sufficient 
for  any  surface  decoration,  the  best  success  in  this  class  of  decora- 
tion being  obtained  by  using  comparatively  simple  designs  and  quiet 
contrasts  of  color. 

If  different  colors  are  used  the  greatest  care  must  be  exercised  in 


Fig.   179. — Surface  Pattern  for  Brick  Panel. 


their  selection,  and  even  with  care  and  thought  it  is  not  granted  to 
all  architects  to  use  color  successfully. 

One  of  the  best  opportunities  for  the  use  of  color  lies  in  the  direc- 
tion of  pattern  work  for  frieze-courses  and  band-courses. 


BRICKWORK  IN  GENERAL. 


347 


Fig.  1/8.  shows  a  simple  brick  diaper  for  a  frieze,  and  Figs.  179 
and  180  an  ornamental  panel  and  a  chimney,  the  latter  designed  by 
Mr.  H.  P.  Marshall. 

Fig.  181  shows  some  diagrams  which  suggest  possibilities  of 
arrangement  in  band  patterns,  as  indicated  in  the  upper  drawings, 


5CAL^  :   \  -         ?  FUtLT 

Fig.   181. — Brick  Band  and  Diaper  Patterns. 


and  in  diaper  work,  as  indicated  in  the  two  lower  drawings.  These 
drawings  are  reproduced  through  the  courtesy  of  the  Eastern  Hy- 
draulic-press Brick  Company,  Philadelphia,  from  "Suggestions  in 
Brickwork."  All  the  designs  in  Fig.  181  are  made  by  the  use  of 
stretchers  only.  Proportions  and  sizes  of  designs  can  be  materially 
changed  by  the  use  of  headers.  The  lower  pattern  suggests  three 
different  shades  of  bricks.  The  coloring  is  optional,  but  strong 
contrasts  should  be  avoided. 

Fig.  182  is  an  interesting  example  of  mediceval  Italian  brickwork 


348 


BUILDING  CONSTRUCTION. 


(Ch.  VII) 


from  San  Stefano,  Bologna,  Italy.  The  patterns  are  partly  filled 
with  pieces  of  stone  and  terra-cotta. 

Fig.  183  is  an  example  of  English  wall  pattern  in  brickwork,  the 
figure  being  in  bricks  of  a  slightly  lighter  shade  than  that  of  the  wall 
itself.  The  detail  is  from  a  residence  in  North  Mymms,  Hertford- 
shire, England. 

Surface  patterns  should  generally  be  flush  with  the  walls.  When 


1      I  I 


I   I .  ■  I 


]  r 


r  r 


.     1     1     1  1 

'  1  '  1  '  

1 

Fig.  182.— Brick  Wall  Surface  from  San  Stefano,  Bologna,  Italy. 

used  as  in  Fig.  180  the  pattern  may  project  j4  i^ch  from  the  surface 
or  panels. 

Diaper  work  may  also  be  used  with  good  effect  on  interior  brick 
walls  of  waiting-rooms,  corridors,  public  baths,  etc. 

3.    CONSTRUCTION  OF  BRICK  WALLS. 

349.  GENERAL  CONSIDERATIONS.— The  proper  construc- 
tion of  a  brick  building  involves  many  things  besides  the  mere  lay- 
ing of  one  brick  on  top  of  another  with  a  bed  of  mortar  between. 
The  manner  of  laying  or  bedding  the  bricks  and  the  general  methods 


CONSTRUCTION  OF  BRICK  WALLS. 


349 


of  doing  the  work  having  been  considered,  we  will  next  consider 
the  details  of  construction  required  to  obtain  strong  and  durable 
walls,  and  the  precautions  to  be  taken  to  prevent  settlements  and 
cracks  and  to  adapt  the  work  to  the  purposes  for  which  it  is 
intended. 

Aside  from  the  quality  of  the  materials  and  the  character  of  the 
work,  the  bonding  of  a  wall  has  the  most  to  do  with  its  strength. 


4  — 

 M  

— 1= — 

1       1       1       1                     1       1       1  1 

1    1     I    1             1    1    1  1 

II              II              II  II 

 ^  

 rV  : — W  VS^ — 

'  1  'l   1  'l  '        l'  1   1 ' l' 

,0'  ^ 

II                 II  II 

I!      !  , 

11          -11  II 

Fig.  183.— Detail  from  Residence,  North  Mymms,  Hertfordshire,  England. 


350.  BOND  IN  BRICKWORK.— Bond  in  brickwork  is  the 
arrangement  of  the  bricks  adopted  for  the  purpose  o^  tying  all  parts 
of  a  wall  together  by  means  of  the  weight  resting  on  the  bricks,  and 
also  for  the  purpose  of  distributing  the  effects  of  a  concentrated 
weight  over  an  ever-increasing  area. 

Common  Bond.— A  brick  laid  with  its  long  sides  parallel  to  the 
face  of  the  wall  is  called  a  "stretcher,"  and  with  its  long  sides  at 
right-angles  to  the  face  of  the  wall  a  "header."  Common  brick  walls 
in  this  country  are  almost  universally  built  by  laying  all  the  bricks  as 


350 


BUILDIXG  CONSTRUCTION.         (Ch.  VII) 


stretchers  for  from  four  to  six  courses,  and  then  by  laying  a  course 
of  headers  as  shown  in  Fig.  184.  When  a  wall  is  more  than  one 
brick  in  thickness,  the  heading  courses  should  be  arranged  as  at 
cither  A  or  B,  Fig.  185.  For  first-class  work  such  a  wall  should  be 
bonded  with  a  heading  course  every  sixth  course. 

Plumb  Bond  or  Diagonal  Bond. — This  is  sometimes  called  ''Amer- 
ican bond,"  and  is  generally  used  when  the  walls  are  faced  with 
pressed  bricks.  All  the  face-bricks  are  laid  as  stretchers  with  the 
joints  plumb  above  each  other  from  bottom  to  top  of  walls,  as  shown 
at  A,  Fig.  186.   The  bonding  of  the  face-bricks  to  the  common  bricks 


Fig.    184. — Common  Bond. 


Fig.   185. — Cross-section  of 
Common   Bond  Brick 
Wall. 


is  accomplished  by  clipping  ofif  the  back  corners  of  the  face-bricks 
in  every  sixth  or  seventh  course  and  by  laying  diagonal  headers 
behind,  as  shown  at  B,  Fig.  186.  This  does  not  make  as  strong  a 
tie  as  the  use  of  regular  headers,  but  if  carefully  done  it  appears 


Fig.   186.— Plumb  Bond. 

to  answer  for  some  purposes.  Very  often  where  this  bond  is  used 
only  one  corner  of  each  face-brick  in  the  outside  course  is  clipped,  so 
that  only  half  as  many  diagonal  bricks,  or  headers,  as  are  indicated 
in  Fig.  186,  are  used.  This  of  course  does  not  make  as  strong  a 
bond  as  when  both  of  the  back  corners  are  clipped.  In  walls  exceed- 
ing one  story  in  height  the  architect  should  see  that  both  corners 
are  clipped.  The  strongest  method  of  bonding  for  face-bricks  is 
by  the  Flemish  or  cross  bonds,  described  further  on.  The  objec- 
tion to  these  bonds,  however,  .is  the  increased  expense  occasioned 
by  using  so  many  face-brick  headers,  and  also  the  fact  that  the  face- 


CONSTRUCTION  Of  BRICK  WALLS.  331 


bricks  and  common  bricks  cannot  usually  be  laid  so  as  to  come  out 
to  exactly  the  same  heights.  In  this  case  it  is  necessary  to  clip 
the  common  bricks  if  face-brick  headers  are  used  in  every  course^ 
or  even  in  every  third  or  fourth  course. 

Face-bricks,  when  laid  as  in  Fig.  186,  are  often  tied  to  the  back- 
ing, as  shown  in  Fig.  187,  by  pieces  of  galvanized-iron  or  tin,  which 
have  their  ends  turned  over  stiflf  wires,  about  4  inches  long.  The 
wires  are  not  absolutely  essential,  but  should  always  be  used  in  first- 
class  work.  Still  better  ties  for  bonding  face-bricks  to  the  backing- 
are  the  Morse  wall-ties,  shown  in  Fig.  188,  or  similar  ties. 

These  ties  are  made  from  -'/^.^  and  ^-inch  galvanized-steel  wire, 
7,  9,  12  and  16  inches  in  length.  The  / .^,,-'mch  wire  is  used  for 
ordinary  pressed  brickwork,  and  the  ^-inch  size  for  very  closely 


Fig.    187. — ]\Ietal    Tie   for   Face-brick  Fig.  i88. — Morse  Wall-tie  for  Face-brick 

and  Backing.  and  Backing. 


laid  w^ork.  These  ties,  or  similar  ties,  are  now  very  extensively 
Ased  in  the  eastern  portion  of  the  country. 

One  advantage  obtained  in  using  metal  ties  is  that  it  is  not  neces- 
sary to  have  the  joints  in  the  face-work  and  backing  on  the  same 
level,  as  the  ties  can  be  bent  to  conform  to  the  dififerences  in  level, 
as  shown  in  Fig.  187.  Face-bricks  bonded  in  this  way  should  be  tied 
at  least  every  fourth  course  with  one  tie  to  each  face-brick. 

The  common  American  practice  of  laying  all  the  facing  bricks 
as  stretchers,  with  ^-inch  joints,  is  peculiar  to  this  country,  and  is 
recognized  the  world  over  as  thoroughly  bad,  constructively  and 
artistically.  Such  facings  are  mere  veneers  and  contribute  but  little 
to  the  strength  of  walls.  The  building  laws  of  New  York,  San 
Francisco  and  some  other  cities  require  that  they  be  ignored  in  com- 


352 


BUILDING  CONSTRUCTION, 


(Ch.  VII) 


pitting  the  necessary  thickness  of  exterior  walls;  while  the  Boston 
law  requires  full  headers  and  prohibits  ''diagonal  bond/' 

''This  class  of  work  is  laid  up  with  joints  which  are  too  thin  to 
be  of  use  constructively,  and  which  rob  the  work  of  all  character, 
giving  to  it  a  hard,  dry,  sleek  appearance,  that  appeals  to  no  artistic 
instinct."* 

The  better  method  is  to  lay  the  facings  on  even  beds  with  the 
backings  and  to  bond  with  headers  in  such  an  arrangement  as  will 
best  suit  the  architectural  purposes  of  the  designer.  Thick  joints 
and  headers  give  character  and  texture  to  the  wall  surfaces,  and 
•every  different  arrangement  of  headers  has  its  own  decorative  value. 
Figs.  i89,t  i9ot  and  191  are  good  examples. 

"The  supposed  economy  of  the  common  method  will 

be  found,  upon  examinaton,  not  to  be  economical,  but  the  reverse.''^ 
The  principal  additional  expense  in  bonded  work  is  in  the  labor. 
Our  bricklayers  are  generally  not  accustomed  to  such  work  and  take 
more  time  per  square  foot  of  wall. 


Fig.  189. — Brickwork  for  Singer  Building,  New  York.    Joints  Recessed  Three-eighths  of  an 

Inch. 


English  Bond. — Fig.  192.  This  is  a  method  of  bonding  much  used 
in  England,  and  consists  of  alternate  header  and  stretcher  courses. 
It  is  probably  the  strongest  method  of  bonding  common  bricks,  but 
is  not  applicable  where  face-bricks  are  used  in  the  usual  American 
manner.  It  does  not  make  very  attractive  work,  and  is  scarcely  ever 
used  in  this  country. 

Flemish  Bond. — This  is  shown  in  Fig.  193,  and  consists  of  alter- 

*  Mr.  Ernest  Flagg,  in  The  Brickbuilder.  Vol.  7.  No.  12. 

t  These  and  other  drawings  are  reproduced  through  the  courtesy  of  The  Brick- 
builder.  For  Figs.  189  and  190  see  \^ol.  7.  No.  72,  pages  259  and  260.  Fig.  189  shows 
brickwork  in  the  Singer  building,  New  York;  Fig.  190  shows  brickwork  in  a  house  for 
the  Clark  estate. 

t  Ernest  Flagg,  The  Brickbuilder,  \'ol.  7,  No.  12. 


CONSTRUCTION  OF  BRICK  WALLS. 


q  ii__zr^ir:zz]L 
zz^r — irni-zTZicnczr 
^==°Tr~ii  II  icn 

VCI]CIIZ]III|i  IE 


rni  11  ^1  

II  II      II  II 

II     ~ii  ii  ^   II  "1 

1  1 

r — II  II  iir 

rni  oc_ 

Fig.  190. — Brickwork  of  House  for  Clark  Estate. 


T  r 


rill 


Fig.  191. — Brickwork.    Interior  in  St.  Bartholomew's  Church,  Brighton,  England. 


354 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


nate  headers  and  stretchers  in  every  course,  every  header  being 
immediately  over  the  middle  of  a  stretcher  in  the  course  below. 
Closers  (a)  are  inserted  in  alternate  courses  next  to  the  corner  head- 
ers to  form  the  necessary  lap.  This  makes  a  very  strong  bond.  A 
modification  of  this  bond,  which  consists  in  laying  every  fifth  course 
with  alternate  headers  and  stretchers,  is  sometimes  adopted.  It 


Fig.   1 9 J. — English  Bond. 


Fig.  193. — Flemish  Bond. 


makes  stronger  work  than  the  diagonal  bond  and  looks  about  as 
well. 

English  Cross  Bond. — This  is  a  variety  of  English  bond  and  is  said 
to  be  much  used  in  Holland,  its  name  being  suggested  by  the  appear- 
ance of  the  surface,  on  which  the  bricks  seem  to  arrange  themselves 
into  St.  Andrew's  crosses.  It  differs  from  ordinary  English  bond 
only  in  having  the  stretchers  of  the  successive  stretcher  courses 
break  joint  with  each  other,  as  well  as  with  the  headers  in  the 
adjoining  courses  on  the  face  of  the  wall,  as  shown  in  Fig.  194. 
This  makes  a  iijuch  better-looking  wall  than  results  from  the 
ordinary  English  bond. 

351.  HOOP-IRON  BOND  IN  BRICKWORK.— Pieces  of 
hoop-iron  are  often  laid  flat  in  the  bed-joints  of  brickwork  to 
increase  its  longitudinal  tenacity  and 
to  prevent  cracks  due  to  unequal  set- 
tlement. The  ends  of  the  iron  should 
be  turned  down  about  2  inches  and 
inserted  in  the  vertical  joints.  Noth- 
ing less  than  No.  18  iron  should  be 
used,  and  the  holding  power  of  the 
ties  may  be  greatly  improved  by  dipping  them  in  hot  tar  and  then 
covering  them  with  sand.  Hoop-iron  bond  is  strongly  to  be  recom- 
mended for  strengthening  brick  arches  and  the  walls  above  them, 
the  walls  of  towers,  the  joining  of  interior  with  exterior  walls,  etc. 
Twisted  iron  bars  are  still  better  for  this  purpose. 

352.  ANCHORING  BRICK  WALLS.— Although  this  belongs 


94. — Cross  Bond. 


CONSTRUCTION  OF  BRICK  WALLS,  355 


more  espe^ally  to  the  carpenter's  work,  it  is  mentioned  here  as  a 
very  important  detail  in  securing  the  stabiHty  of  walls  and  in  pre- 
venting any  from  inclining  outward. 

Brick  walls  should  be -tied  to  every  floor  at  least  once  in  every 
6  lineal  feet,  either  by  the  use  of  iron  anchors,  built  solidly  into  the 
walls  and  spiked  to  the  floor  joists,  or  by  means  of  box-anchors  or 
joist-hangers. 

The  forms  of  iron  anchors  commonly  used  for  this  purpose  are 


Fig.   195. — Iron  Anchors  for  Floor  Fig.   197. — Destructive  Effect  of 

Joists.  Anchor  at  Top  of  Joist. 


those  shown  in  Fig.  195,  the  one  shown  at  a  being  the  most  common, 
and  about  as  good  as  any.  The  anchor  shown  at  b  answers  the  pur- 
pose just  as  well,  but  costs  a  little  more.  |^nchors  like  a  and  b  are 
spiked  to  the  sides  of  the  floor  joists  and  built  into  the  walls,  as 
shown  in  Fig.  196. 

In  the  case  of  side  or  rear  walls,  where  appearances  are  not  oi 
much  consequence,  it  is  better  to  have  the  anchors  pass  clear  through 
them,  with  plates  on  the  outside,  as  such  anchors  take  much  bet- 
ter hold  on  walls  than  is  possible  when  they  are  built  into  the  middle 
parts  only.    The  form  of  the  cheapest  anchor  for  this  purpose 


356 


BUILDING  CONSTRUCTION,        (Ch.  VII) 


is  that  shown  at  c.  The  anchor  has  a  thin  plate  of  ii^n  dowelled 
and  upset  on  the  outer  end.  Anchors  of  this  style  may  be  used  also 
for  building-  into  the  middle  of  the  walls. 

Where  the  ends  of  girders  are  to  be  anchored,  or  where  particu- 
larly strong  anchors  are  desired,  the  form  shown  at  d  is  undoubtedly 
the  best.  These  anchors  are  made  from  ^-inch  bolts,  flattened  out 
for  spiking  to  the  joists  and  provided  with  cast-iron  star  washers. 
An  anchor  of  this  kind  possesses  the  advantage  of  having  a  nut 
on  the  outer  end,  which  can  be  tightened  up  if  desired  after  the 
walls  are  built. 

All  of  these  anchors  should  be  spiked  to  the  sides  of  the  joists  or 
girders,  near  the  bottom,  as  shown  in  Fig.  196.  The  nearer  an 
anchor  is  placed  to  the  top  of  a  joist  the  greater  will  be  the  destruc- 


Fig.   198. — Duplex  Wall-hangef.  Fig.   199. — Goetz  Box-anchors. 


tive  effect  on  the  wall  by  the  falling  of  the  joist,  as  shown  in 
Fig.  197. 

For  anchoring  walls  that  are  parallel  to  the  joists,  the  anchors 
must  be  spiked  to  the  tops  of  the  joists ;  and  either  they  should  be 
long  enough  to  reach  ovei*  two  joists,  or  pieces  of  i^-inch  boards 
should  be  let  into  the  tops  of  three  or  four  joists  and  the  anchors 
spiked  to  them. 

The  objection  to  all  of  these  anchors  is  that  in  case  the  beams  fall 
during  a  severe  fire  or  from  any  other  cause,  they  are  apt  to  pull 
the  walls  over  with  tffem.  To  overcome  this  objection,  as  well  as 
to  secure  other  advantages,  the  Duplex  wall-hangers,  shown  in 
Fig.  198,  and  the  Goetz  box-anchors,  shown  in  Fig.  199,  have  been 
invented.  These  devices  hold  the  timbers  by  means  of  ribs  or  lugs 
gained  into  their  lower  surfaces.  The  anchoring  is  perhaps  not  as 
efficient  as  is  secured  by  the  anchors  shown  in  Fig.  195,  but  it  is 
ample  for  all  ordinary  conditions,  as  every  joist  is  anchored  when 
these  devices  are  used. 


CONSTRUCTION  OF  BRICK  WALLS. 


357 


These  devices  ofifer  also  the  additional  advantages  of  not  weaken- 
ing the  walls,  while  they  increase  the  bearings  of  the  timbers  and 
reduce  the  possibility  of  dry  rot  to  a  minimum.  They  also  permit 
of  easily  replacing  the  joists  after  a  fire. 

A  stronger  form  of  the  Duplex  is  the  wall-hanger  shown  in  Fig. 


Fig.  200. — Stronger  Form  of 
Duplex  Wall-hanger. 


201. — Goetz  Wall-hc 


200.  The  Goetz  Box-anchor  Company  also  make  wall-hangers  of  a. 
form  shown  in  Fig.  201,  which  have  the  advantage  of  great  simplicity 
and  strength.  The  ''Truss-coN"  wall-hangers,  Fig.  202,  are  well- 
designed  single-plate  pressed-steel  hangers  which  have  satisfied  very 
high  tests  for  strength. 

Wall-hangers  of  the  general  types  illustrated  in  Figs.  198,  200, 


Fig.  202. — The  "Truss-coN" 
Wall-hanger. 


Fig.  203.— Beam  Anchored  to  Party-wall 
Wall-hangers. 


201  and  202  are  especially  desirable  for  party-walls  and  partition 
walls,  as  they  obviate  the  necessity  of  building  the  beams  into  the 
walls  and  permit  the  walls  to  be  as  solid  at  the  floor  levels  as  in  other 
portions.    (See  Fig.  203.) 


358 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


The  importance  of  anchoring  the  joists  to  the  walls,  and  thus  pre- 
venting the  latter  from  being  thrown  outward  either  from  settle- 
ment in  the  foundation  or  from  pressure  exerted  against  the  insides 
of  the  walls,  is  very  great,  and  should  not  be  overlooked  by  the  archi- 
tect. Many  walls,  which  might  have  been  saved  by  proper  anchor- 
ing, have  either  fallen,  or  have  had  to  be  rebuilt. 

353.  CORBELLING  BRICK  WALLS  FOR  FLOOR  JOISTS. 
— In  some  localities  it  is  the  custom  to  form  ledges  to  support  the 
floor  joists  by  building  continuous  corbels  of  three  or  more  courses. 
This  is  done  to  prevent  the  ends  of  the  floor  timbers  from  weakening 
the  walls;  for,  of  course,  wherever  wooden  timbers  are  built  into 

them,  they  make  the  section  or 
bearing  area  of  the  walls  smaller 
by  just  the  amount  of  space 
taken  up  by  the  timbers ;  and  in 
partition  walls  this  is  very  con- 
siderable. 

The  Chicago  Building  Ordi- 
nance provides  that  all  walls,  16 
inches  or  less  in  thickness,  shall 
have  ledges  of  the  thickness  of 
the  furring,  lath  and  plaster  to 
support  the  floor  joists;  and 
in  all  cases  where  ledges  are 
built  they  are  to  be  carried  to 
the  tops  of  the  joists,  as  shown  in  Fig.  204. 

When  walls  are  corbelled"  in  this  way  it  requires  plaster  or  wooden 
cornices,  as  shown  by  the  dotted  lines,  to  give  a  proper  finish  for  the 
angles  of  the  rooms ;  and  for  this  reason  corbelling  is  not  usually 
done  when  not  required  by  law. 

Corbelling  for  floor  joists  should  not  be  attempted  with  soft  or 
poor  bricks. 

354.  CARRYING  UP  BRICK  WALLS  EVENLY.— The 
walls  of  a  building  should  be  carried  up  evenly,  no  part  being  allowed 
to  be  carried  up  more  than  3  feet  above  any  other  part,  except  where 
it  is  stopped  by  an  opening.  The  building  up  of  one  part  of  a  wall 
ahead  of  the  adjacent  parts  tends  to  cause  unequal  settlements;  and 
the  joints  in  the  higher  parts  setting  before  the  rest  is  added,  the 
brickwork  which  is  laid  last  is  apt  to  settle  away  from  the  other  and 
to  weaken  the  walls,  besides  marring  their  appearance.   Whenever  it 


Fig.  204. — Brick  Corbel  for  Floor  Joists. 


CONSTRUCTIOX  OF  BRICK  IV ALLS. 


359 


is  necessary  to  carry  one  part  of  a  wall  higher  than  the  rest  of  it  the 
end  of  the  higher  part  should  be  stepped  or  racked  back,  and  not 
run  up  vertically,  with  only  toothings  left  for  connecting  the  re- 
mainder of  the  work. 

355.  BONDING  OF  BRICK  WALLS  AT  ANGLES.— An 
important  detail  in  the  construction  of  brick  buildings  is  the  secure 
bonding  of  the  front  and  rear  walls  to  the  side  or  partition  walls. 
When  practicable,  both  walls  should  be  carried  up  together,  so  that 
each  course  of  bricks  in  both  walls  may  be  well  bonded  together. 
If,  in  order  to  avoid  delay,  the  side  walls  must  be  built  up  ahead 
of  the  front  wall,  the  ends  of  the  side  walls  should  be  built  with 
toothings,  as  shown  in  Fig.  205,  eight  or  nine  courses  high,  into 


o 
d 


1  '  '  1 

.1  r 

rr — S 

I 

a 

b 

r  r- 

c 

Fig.  205. — Toothing  and  Anchoring 
of  Side  Brick  Walls. 


Fig.  206. — Cracks  in  Brick  Walls 
Caused  by  Piers  and  Openings. 


which  the  backing  of  the  front  wall  should  be  bonded.  In  addition 
to  the  brick  bonding,  anchors  made  of  ^  by  2-inch  wrought-iron, 
with  one  end  turned  up  2  inches  and  the  other  welded  around  a 
^-inch  round  bar,  should  be  built  into  the  side  walls  about  every  5 
feet  in  height,  as  shown  in  the  figure.  The  anchors  should  be  of 
such  lengths  that  the  rods  will  be  at  least  8  inches  in  from  the  back 
of  the  front  wall  and  extend  at  least  17  inches  into  the  side  walls.^ 
The  building  regulations  of  most  of  the  larger  cities  require  that  all 
intersecting  brick  walls  shall  be  tied  together  in  this  way. 

356.  OPENINGS  IN  BRICK  WALLS.— The  locations  of  all 
door  and  window  openings  in  brick  walls  should  be  carefully  con- 


360 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


sidered,  not  only  as  regards  convenience,  but  also  as  to  their  effect 
on  the  strength  of  the  walls.  The  combined  widths  of  the  openings 
in  any  bearing  wall  should  not  much  exceed  one-fourth  of  the  length 
of  that  wall ;  and  as  far  as  possible  the  openings  in  the  different 
stories  should  be  over  each  other.  The  placing  of  a  window  either 
under  a  pier  or  directly  over  a  narrow  mullion,  as  at  a  or  b,  Fig. 
206,  should  be  especially  avoided.  If  windows  must  be  used  in  these 
positions,  steel  beams  should  be  placed  over  the  windows  a  and  c,  as 
a  stone  lintel  or  a  brick  arch  would  be  quite  sure  to  crack  from  the 

combined  effects  of  the  load  and  the  set- 
tlement of  the  joints  in  the  brickwork  on 
either  side  of  the  windows. 

All  openings  in  exterior  walls  should 
have  either  relieving-arches  or  cast-iron 
or  steel  beams  behind  the  stone  caps  or 
face-arches.  Ordinary  relieving-arches 
(see  Article  372)  are  commonly  used 
where  the  widths  of  the  openings  are  less 
Joining  New  to  Old  Br  ick      than  6  feet,  and  steel  beams  where  the 

Walls 

widths  are  greater.  In  bearing  walls, 
where  the  tops  of  the  openings  come  within  12  inches  of  the  bot- 
toms of  the  floor  joists,  it  is  hardly  safe  to  use  relieving-arches, 
unless  the  floor  loads  are  very  light. 

For  door  openings  in  unplastered  brick  partitions,  cast-iron  lintels 
may  be  used  to  good  advantage,  as  they  give  smooth,  level  soffits  to 
the  openings  and  show  only  narrow  strips  of  metal  on  the  faces  of 
the  walls. 

357.  JOINING  NEW  TO  OLD  BRICK  WALLS.— When  a 
new  wall  is  to  be  joined  to  an  old  one,  at  right-angles,  a  groove 
should  be  cut  in  the  old  wall  similar  to  that  shown  in  Fig.  159  for 

^  the  new  wall  to  fit  into  and  for  the  purpose  of  allowing  it  to  settle 
independently.  A  cheaper  method,  and  one  more  commonly  used  in 
light  work,  is  to  nail  a  scantling,  a  2-inch  by  4-inch  piece  of  timber, 
to  the  wall  of  the  old  building,  so  that  it  will  come  in  the  middle  of 
the  new  wall,  as  shown  in  Fig.  207.  A  similar  method  can  be  used 
for  joining  the  ends  of  old  and  new  walls.  New  work  should  never 
be  toothed  to  old  work  unless  the  former  is  laid  in  cement. 

358.  THICKNESSES  OF  BRICK  WALLS.— There  is  no  prac^ 
tical  rule  by  which  it  is  possible  to  calculate  the  necessary  thickness 


CONSTRUCTION    OF   BRICK    WALLS.  361 


of  a  brick  wall,  as  the  resistance  to  crushing,  which  is  the  only 
direct  stress,  is  usually  only  a  minor  consideration. 

We  must  therefore  rely  principally  upon  experience  in  determin- 
ing the  thicknesses  of  walls  for  any  given  building,  unless  the  con- 
struction of  the  building  is  controlled  by  municipal  or  State  regula- 
tions. 

In  nearly  all  of  the  larger  cities  of  the  country  the  minimum  thick- 
nesses of  the  walls  are  prescribed  by  law  or  ordinance ;  and  as  these 
requirements  are  generally  ample  they  are  usually  adhered  to  by 
architects  when  designing  brick  buildings. 

TABLE  XXVL='^ 
Thicknesses  of  Walls  of  Mercantile  Buildings  in  Various 
Cities,  Shown  Graphically. 


Cities 


JBoston 

Sam  ri-arioSsco 

.Den.ver 

Minneapolis 

Chicago 

Philadelphia 

Memphis 
Kevy  Yoi'k 

jBoston 
San  Erancisco 
.Denver 
.Minneapolis 
Chicago 
-■Philadelphia 
Memphis 
J^lew  York 

San  Francisco 

Denver 

Minneapolis 

Chicago 

Philadelphia 

Memphis 

.New  York 

San  Trancisco 

Denver 

^Minneapolis 

Chicago 

Philadelphia 

Memphis 


s  §       ^  ^  ^ 


Cities 


San  Francisco 

Denver 

Minneapolis 

Chicago 

Philadelphia 

.Memphis 

New  York 

P.uston 

Denver 

Munieapolis 

Chicago 

Philadelphia, 

Memphis 

Denver 
Minneapolis 
Chicago 
Philadelphia 
Memphis 
New  York- 
Denver 

Minneapolis 
Chicago 
Philadelphia 
3Iemphis 

Boston 

Minneapolis' 

Chicago 

Philadelphia 

Memphis 

SeAv  YorJi 


Table  XXVI  and  other  matter  of  this  chapter  was  prepared  by  Mr.  Julian  Millard. 
See  also  Tables  X  and  Y  in  Appendix. 


362  BUILDING  CONSTRUCTION.        (Ch.  VII) 


TABLE  XXVII. 
Maximum  Story-heights  for  Thicknesses  in  Table  XXVI. 


Cities 

Maximum  story-heighis 

in  feet 

Limits  of 
lengths  in  feet 

1st 

2d 

Inter- 
mediate 

Top 

More 
than 

Less 
than 

40 

105 

is* 

15* 

14* 

75 

125 

100 

4of 

14 

12 

16 

40 

125 

18* 

15^- 

14* 

100 

*  In  the  clear. 

t  Applies  to  walls  over  60  feet  high. 


Table  XXVI  shows  graphically  the  thicknesses  of  walls  of  ware- 
houses and  mercantile  buildings  in  eight  representative  American 
cities.  In  this  table  each  vertical  subdivision  represents  ten  feet  of 
wall  height  and  each  horizontal  line  represents  a  half-brick  (4  or 
inches)  of  wall  thickness.  Thus,  three  lines  represent  a  12  or 
13-inch  wall.  The  short  cross  lines  show  story-heights.  If  the  law 
limits  heights  of  stories,  such  limits  are  indicated  by  the  small  circles. 

Table  XXVII  shows  the  maximum  story-heights  in  feet  for  which 
the  thicknesses  in  Table  XXVI  apply ;  and  the  minimum  and  maxi- 
mum lengths  (not  heights)  in  feet  within  which  the  thicknesses  of 
Table  XXVI  apply.  The  columns  marked  "limits  of  lengths"  refer 
to  lengths  unsupported  by  buttresses  or  cross-walls. 

Many  ordinances  require  that  in  computing  the  thickness  of 
exterior  walls,  facings  in  ''running  bond"  shall  not  be  included. 

Although  there  is  some  difiference  in  the  thicknesses  of  walls  given 
it|i  the  tables,  a  general  rule  might  be  deduced  from  the  table,  for 
mercantile  buildings  over  four  stories  in  height,  which  would  be 
somewhat  as  follows : 

For  bricks  equal  to  those  used  in  Boston  or  Chicago,  make  the 
thickness  of  the  zvalls  of  the  three  upper  stories  16  inches;  of  the 
next  three  below,  20  inches ;  of  the  next  three,  24  inches ;  and  the 
next  three,  28  inches.  For  a  poorer  quality  of  material,  make  the 
walls  of  the  two  upper  stories  only,  16  inches  thick;  those  of  the  next 
three,  20  inches ;  and  so  on  down. 


CONSTRUCTION  OF  BRICK  WALLS.  363 


In  buildings  less  than  five  stories  in  height  the  top  story  may  be 

12  inches  in  thickness. 

For  the  walls  of  dwellings,  13  inches  and  9  inches  may  be  used  for 
two-story  buildings ;  for  three-story  buildings  the  walls  should  be 

13  inches  thick  the  entire  height  above  the  basement;  and  for  four- 
story  buildmgs  17  inches  in  the  first  story  and  13  inches  for  the  entire 
height  above. 

In  determining  the  thickness  of  walls  the  following  five  general 
principles  should  be  recognized : 

First.    Walls  of  warehouses  and  mercantile  buildings  should  be 
heavier  than  those  used  for  living  or  office  purposes. 

Second.  Clear  spans  exceeding  25  feet  and  unusually  high  ^ 
stories  require  thicker  walls. 

Third.  Great  length  is  a  source  of  weakness  in  a  wall,  and  its 
thickness  should  be  increased  4  inches  for  every  25  feet  over  about 
ICQ  feet  in  length. 

Fourth.    Walls  containing  over  33  per  cent  of  openings  should  be 
increased  in  thickness. 

Fifth.  Partition  walls,  if  not  over  60  feet  long,  may  be  4  inches 
less  in  thickness  than  the  outside  walls,  but  no  partition  should  be 
less  than  8  inches  thick. 

359.  BRICK  PARTY-WALLS.— There  is  much  diversity  in 
building  regulations  regarding  the  thickness  of  party-walls,  al- 
though they  all  agree  that  such  walls  should  never  be  less  than  12 
inches  thick.  About  one-half  of  the  laws  require  the  party-walls  to 
be  of  the  same  thickness  as  exterior  walls ;  the  remainder  are  about 
equally  divided  between  making  the  party-walls  4  inches  thicker 
or  4  inches  thinner  than  if  they  were  independent  side  walls. 

When  the  walls  are  proportioned  by  the  rule  previously  given,  the 
author  believes  that  the  thickness  of  the  party-walls  should  be 
increased  4  inches  in  each  story.  The  floor  load  on  a  party-wall  is 
obviously  Iwice  that  on  the  side  walls,  and  the  necessity  for  thorough 
fire-protection  is  greater  in  the  case  of  party-walls  than  in  that  of 
other  walls. 

360.  BRICK  CURTAIN-WALLS.— In  buildings  of  the  skele- 
ton type  the  outer  masonry  walls  are  usually  supported  either  in 
every  story  or  every  other  story  by  the  steel  framework,  a*nd  carry 
nothing  but  their  own  weight.  Such  walls  may,  therefore,  be  con- 
sidered as  only  one  or  two  stories  high,  and  are  often  made  only 


3^4 


BUILDING  CONSTRUCTION. 


(Ch.  VII) 


12  inches  thick  for  the  whole  height  of  a  twelve  or  fifteen-story 
building  unless  building  laws  require  a  greater  thickness. 

361.  WOOD  IN  BRICK  WALLS.— As  a  rule,  no  more  wood- 
work should  be  placed  in  brick  walls  than  is  absolutely  necessary. 
Wooden  lintels  for  supporting  brick  walls  are  objectionable  not  only 
on  account  of  their  non-resistance  to  fire,  but  also  on  account  of 
their  tendency  to  shrink.  It  is  generally  impossible  to  obtain  fram- 
ing lumber  that  is  thoroughly  dry,  and  when  a  brick  wall  is  partially 
supported  by  a  wooden  lintel  a  crack  is  quite  sure  to  develop  sooner 
or  later  in  the  manner  shown  in  Fig.  208.  The  crack  is  obviously 
caused  by  the  shrmkage  of  the  lintel,  which  permits  the  portion 
.of  the  wall  supported  on  it  to  settle  by  an  amount  equal  to  the 
shrinkage  of  the  wood.  The  portion  of  the  wall 
a,  being  supported  on  the  brick  pier,  does  not 
settle. 

Bond-timbers,  or  pieces  of  studding  laid  under 
the  ends  of  the  floor  joists,  are  also  objection- 
able, because  they  are  quite  sure  to  shrink,  leav- 
ing the  walls  above  them  unsupported.  Bond- 
timbers  are  very  convenient  for  the  carpenters. 


Fig.  2o8.-Cracks  in  ^s  they  givc  a  level  bearing  for  the  floor  joists. 


^bTsJ^inkag''e"'of^    ^^^^  distribute  the  weight  over  the  brickwork; 
Wood  Lintel.       ^^^^  ^YiQy  should  ucvcr  be  used  in  buildings  which 
are  over  two  stories  in  height,  nor  in  walls  which  are  less  than  12 
inches  thick.     If  used  at  all,  they  should  be  selected  from  the 
driest  lumber  that  can  be  obtained. 

For  the  proper  use  of  wooden  lintels  under  relieving-arches  see 
Article  372. 

Strips  of  wood  are  sometimes  built  into  walls  to.  form  a  nailing 
for  the  wood  finish  or  for  the  furring  strips.  Such  strips  should 
not  be  used  in  buildings  over  two  stories  in  height,  and  should  not 
be  over  ^  of  an  inch  thick,  so  that  they  may  take  the  place  of  the 
mortar  joints. 

Wooden  bricks  also,  or  blocks  of  wood  of  the  size  of  bricks,  are 
sometimes  built  into  brick  walls  to  provide  nailings  for  furring 
strips,  door  frames,  etc.  These  not  only  tend  to  weaken  the  walls, 
but  the}^  also  generally  shrink  enough  to  become  loose,  thereby 
losing  their  holding  power. 

Plugs. — It  is  a  common  practice  to  drill  holes  in  the  brickwork 
and  to  drive  in  wood  plugs  for  the  nailings.    While  these  plugs  are 


CONSTRUCTION  OF .  BRICK  WALLS. 


365 


generally  efficient,  they  cannot  be  depended  upon,  as  they  are  often 
loosened  by  the  shrinkage  or  split  by  the  nails. 

In  first-class  work  nailings  should  be  provided  as  the  walls  are 
built  by  porous  terra-cotta  blocks  or  by  the  Rutty  metal  wall- 
plugs,  shown  in  Fig.  209.    The  porous  terra-cotta  will  hold  nails 


almost  as  well  as  timber  will,  but  greater  dependence  can  be  placed 
upon  the  metal  plugs  than  upon  either  of  the  others.  These  wall- 
plugs  are  made  of  steel,  thoroughly  japanned,  and  may  be* obtained 
in  either  of  two  forms.  One  type  is  intended  to  be  set  in  the 
joints  with  the  edges  flush  with  the  masonry,  as  in  Fig.  210.  The 
others,  called  "non-furring  plugs.,"  Fig.  211,  are  set  with  their  faces 
J4  of  an  inch  out  from  the  masonry,  as  in  Fig.  212.  Wood  furring- 
strips  or  metal-lath  may  be  nailed  directly  to  these,  and  thus  be 
entirely  insulated  from  the  walls. 

362.  CRACKS  IN  BRICK  WALLS.— It  is  a  very  common 
thing  to  see  cracks  in  brick  walls.  These  cracks  may  be  produced 
by  any  one  of  several  causes. 

Probably  the  most  frequent  cause  of  the  cracking  of  masonry 
walls  is  the  settlement  of  the  foundations,  due  either  to  their  im- 
proper design  or  to  a  settlement  of  the  ground  caused  by  excessive 
moisture.  A  strict  observance  of  the  rules  laid  down  in  Articles 
25,  32  and  33  will  generally  prevent  cracks  due  to  faulty  founda- 
tions. 


Fig.   210. — The  Rutty 
Steel  Wall-plug. 
Face  Flush  with 
Masonry. 


Fig.  211. — The  Rutty  Non-furring  Wall-plug. 


:^hG  BUILDIXG  construction:         (Ch.  VII)  ' 

The  effect  produced  on  certain  soils  by  a  saturation  with  water 
is  described  in  Article  9. 

Next  to  faulty  foundations,  probably  the  commonest  cause  of 
cracks  in  brick  walls  is  the  use  of  wooden  lintels,  as  described  in 
Article  261. 

Besides  the  cracks  resulting  from  these  causes  are  those  which 
often  appear  over  openings,  and  which  are  due  to  the  settlement  of 
the  mortar  joints  in  the  piers  or  to  the  spreading  of  arches. 

Small  cracks  are  commonly  seen  just  above  the  ends  of  door  sills 
■or  window  sills,  as  shown  in  Fig.  213.  Such  cracks  generally  appear 
near  the  bottom^s  of  high  walls,  and  are  caused  by  the  compression 
of  the  mortar  in  the  lower  joints  of  the  piers.  They  may  be 
avoided  by  using  slip-sills,  as  described  in  Article  282,  but  are  not 
likely  to  occur  when  cement  mortar  is  used. 

Another  place  where  cracks  produced  by  the  settlement  of  mortar 
joints  sometimes  occur  is  where  a  low  wall  joins  a  very  high  one. 


Fig.  212. — The  Rutty  Non-furring  Wall-plug.  Fig.  213. — Cracks  Over 

Sills  Caused  by 
Joint  Com- 
pression. 

To  prevent  such  cracks  the  walls  should  be  joined  by  a  slip- joint, 
as  described  in  Articles  315  and  357. 

Cracks  are  generally  miore  likely  to  occur  in  walls  that  are  broken 
by  frequent  openings  than  in  those  that  are  plain  and  unbroken. 

The  use  of  plenty  of  anchors  and  thorough  bonding  does  much 
toward  preventing  cracks. 

363.  DAMP-PROOF  COURSES.— When  buildings  are  built 
on  ground  that  is  continually  moist  or  wet,  the  moisture  is  very 
apt  to  soak  up  into  the  walls  from  the  foundations,  rendering  the 
building  unhealthy  and  often  causing  the  woodwork  to  rot.  To 
prevent  the  moisture  rising  in  this  way  a  horizontal  damp-proof 
.course  should  be  inserted  in  all  walls  below  the  level  of  the  first  floor 


CONSTRUCTION  OF  BRICK  WALLS.  367 


joists.  It  should  be  at  least  6  inches  above  the  highest  level  of  the 
soil  touching  any  part  of  the  outer  walls,  and  should  run  unbroken 
all  around  them  and  at  least  2  feet  into  all  the  cross  walls ;  and  on 
very  wet  ground,  where  the  water  is  but  a  few  feet  below  the  sur- 
face, it  should  be  continuous  through  all  the  walls.  In  buildings  fin- 
ished with  parapet  walls  it  is  also  desirable  to  insert  a  damp-proof 
course  just  above  the  flashings  of  the  roofs  or  gutters  to  prevent 
the  moisture  from  soaking  down  into  the  woodwork  of  the  roof 
and  into  the  walls  below. 

Materials. — These  damp-proof  courses  may  be  formed  of  any  one 
of  several  materials : 

Asphalt. — A  layer  of  rock  asphalt  ^  of  an  inch  thick  makes  an 
excellent  damp-proof  course.  The  surface  to  receive  the  hot  asphalt 
should  be  quite  dry  and  should  be  made  smooth  to  economize  mate- 
rial, and  all  the  joints  should  be  well  flushed  up  with  mortar.  The 
best  asphalts  for  this  purpose  are  the  natural  rock-asphalt  from 
Seyssel,  Val  de  Travers  or  Ragusa,  which  are  imported  into  this 
country  in  the  shape  of  blocks  and  cakes..  When  used  the  cakes  are 
melted  in  large  kettles,  and  mixed  with  a  small  proportion  of  coal- 
tar  and  applied  hot.  One  or  two  layers  of  tarred  felt  also,  imbedded 
in  the  hot  asphalt,  may  be  used  with  good  results. 

"Roofing  slates,  or  even  hard  vitrified  bricks,  two  courses  break-* 
ing  joint,  laid  in  half  cement  and  sand  mortar,  or  such  bricks  laid 
without  any  mortar  in  the  vertical  joints,  form  an  inexpensive  damp 
course."    Glass  also  has  sometimes  been  used  for  this  purpose. 

-Portland  Cement. — A  5^ -inch  layer  of  Portland  cement  mortar, 
mixed  in  the  proportion  of  i  part  of  cement  and  I  of  sand,  will 
often  answer  the  purpose,  but  is  not  as  desirable  as  the  materials 
mentioned  above. 

There  are  many  other  special  preparations  used  for  this  purpose. 

364.  HOLLOW  BRICK  WALLS.  THEIR  OBJECT.— It  is 
well  known  that  solid  brick  walls  readily  absorb  moisture  and  trans- 
mit heat  and  cold.  A  driving  rainstorm  will  often  penetrate  12-inch 
brick  walls  so  as  to  dampen  the  wall-paper  or  soil  the  fresco  deco- 
rations.* It  is  also  known  that  a  house  with  damp  walls  is  unhealthy 
and  a  frequent  cause  of  rheumatism;  besides  this,  the  moisture  in 

*  So-called  solid  brick  walls  are  by  no  means  really  solid,  and  facings,  apparently  tight, 
have  frequent  holes  through  which  water  will  gain  admittance.  There  is.  therefore,  nothing- 
mysterious  in  the  above  statement.  But  if  the  walls  are  made  so  solid  and  dense  that 
they  are  impervious  to  water,  their  conductivity  is  high,  and  the  warm  air  o£  the  interior 
rapidly  deposits  its  moisture  and  dirt  upon  the  walls.  Such  conditions  are  even  more 
unsanitary  than  conditions  resulting  in  moisture  from  the  outside. 


BUILDING  CONSTRUCTION. 


(Ch.  VII> 


the  brickwork  prevents  the  mortar,  if  made  of  Hme,  from  becoming 
hard,  and  is  also  liable  to  communicate  itself  to  the  woodwork, 
thereby  causing-  rot. 

A  building  with  damp  walls  will  also  require  the  consumption  of 
very  much  more  coal  to  warm  it  than  one  with  dry  walls,  as  the 
moisture  must  be  evaporated  before  the  temperature  of  the  walls 
can  be  raised. 

To  overcome  these  objections  to  solid  brick  walls,  particularly  in 
residences  and  school-houses,  hollow  or  vaulted  walls  have  been 
used,  and  earnestly  recommended  by  various  persons. 

Theoretically,  a  hollow  wall  should  prevent  the  passage  of  moist- 
ure through  it,  or  insulate  the  interior  from  the  exterior  surfaces, 
and  by  providing  air-spaces  in  the  walls,  make  the  building  much 
cooler  in  summer  and  warmer  in  winter. 

In  the  actual  construction  of  the  walls,  however,  certain  difficulties 
are  met  with,  which,  to  a  considerable  extent,  offset  the  advantages ; 
so  that  hollow  walls  are  comparatively  little  used  in  this  country. 

The  author  believes,  however,  that  their  use  might  be  much 
extended  with  beneficial  results,  especially  for  isolated  buildings. 

To  obtain  the  full  benefit  of  the  air-spaces  they  should  be  con- 
tinuous throughout  the  walls,  and  the  bonds  or  connections  between 
the  two  parts  should  be  of  such  niaterial  and  of  such  shape  that 
the  moisture  which  penetrates  the  outer  portions  cannot  be  conveyed 
across  to  the  inner  portions. 

To  provide  continuous  air-spaces  in  walls  penetrated  by  openings 
is  practically  impossible,  although  it  may  be  quite  closely  approxi- 
mated. 

The  objections  commonly  urged  against  vaulted  walls  are  in- 
creased cost  and  increased  ground  area,  the  latter  being  an  impor- 
tant consideration  in  city  buildings. 

365.  METHODS  OF  HOLLOW-WALL  CONSTRUCTION. 
— There  are  several  ways  of  constructing  hollow  or  vaulted  walls. 
They  differ  principally  in  the  method  of  bonding  and  in  the  thick- 
ness of  the  inner  and  the  outer  portions  of  the  walls. 

Generally,  at  least  one  portion  of  the  wall  must  be  made  8  inches 
thick  to  sustain  the  weight  of  the  floors,  the  other  portion  being  only 
4  inches  thick.  The  thicker  portion  is  more  commonly  placed  on 
the  outside  of  the  walls  ;  but  this  necessitates  extending  the  floor 
joists  across  the  air-space,  thus  to  a  great  extent  neutralizing  the 
"benefits  expected  to  be  derived  from  it.    By  this  method  the  thicker 


CONSTRUCTION  OF  BRICK  WALLS. 


369 


Fig. 


214. — Brick     Hollow-wall  Construction 
Two-story  Buildings. 


portion  of  the  wall  is  still  sub- 
jected to  the  injurious  effects 
of  outside  moisture. 

For  two-story  buildings  the 
author  recommends    that  the 
walls  be  constructed  as  shown 
Fig.  214.    If  the  wall-plates 
come  above  the  attic  joists  the 
latter  may  be  supported  on  two 
4-inch  walls  if  well  built.  If 
the  bricks  are  not  of  good  qual- 
ity the  inner  8-inch  wall  should  be  con- 
tinued to  the  upper  joists. 

When  the  bricks,  mortar  and  work- 
manship are  of  the  best  quality  there  is 
no  reason  why  this  construction  should 
not  answer  for  even  four  or  five-story 
buildings,  if  used  only  for  dwelling  or 
lodging  purposes,  by  making  the  inner 
portions  8  inches  thick  the  full  height, 
and   by    increasing  the 
width  of  the  air-spaces 
to  6  inches. 

For  warehouses  the 
bearing  wall  in  the 
lower  stories  should  be 
increased  in  thickness. 

A  hollow  w^all  of  a 
given  number  of  bricks, 
securely  bonded,  is  much 
more  stable  than  a  solid 
wall  of  the  same  number 
of  bricks,  and  will  also 
withstand  fire  better.  It 
requires  much  better 
workmanship,  however,, 
than  is  '  generally  be- 
stowed on  solid  walls,* 


*  A  4-inch  brick  wall  is  more  likely  than  a  thicker  wall  to  be  solid  and  to  have 
well-filled  joints. 


370 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


Fig.  215. — Brick  Hollow  Walls  for 
Cheap  Cottage  Constructions 


and  the  mortar,  particularly  in  the  outer 
portions,  must  be  of  the  best  quality, 
and  preferably  of  cement. 

The  outer  and  inner  walls  should  be 
built  of  the  same  kind  of  mortar  and 
at  the  same  time',  to  avoid  unequal  set- 
tlement. For  country  and  suburban 
houses  the  following,  shown  in  Fig. 
215,  gives  a  reasonably  good  hollow- 
wall  construction  at  small  expense : 
The  foundation  walls  are  made  solid 
to  the  bottoms  of  the  first-story  joists. 
Upon  these  are  built  two  4-inch  walls, 
2  inches  apart,  bonded  across  with  wire 
bonds.  The  walls  are  made  solid  for 
two  or  three  courses  below  the  second- 
floor  joists,  and  thence  continued  as 
hollow  walls  to  the  second  course  below 
the  ceiling.  Frcm  this  level  they  are 
made  solid  up  to  plates,  reducing  to  8 
inches  in  thickness  back  of  the  cornice. 
The  corners  are  made  solid,  and  4-inch 
solid  withes  are  built  at  the  jambs  of 
openings.  The  heads  are  made  solid. 
A  wire  bo«nd  is  used  in  every  square 
foot  of  wall  surface.  A  few  holes  left 
through  the  solid  parts,  giving  air  cir- 
culation from  cellar  to  attic,  will  tend 
to  quickly  evaporate  any  moisture  be- 
fore it  passes  in  any  perceptible  quan- 
tity from  the  outside  to  the  inside. 

Cement  mortar  or  lime-and-cement 
mortar  should  be  used,  although  in  dry 
climates  lime  mortar  is  used  with  suc- 
cess. This  construction  is  very  stable 
when  used  in  houses  not  over  two 
stories  in  height.  It  requires  neither 
furring  nor  lath,  and  usually  is  no 
more  expensive  than  solid  walls,  furred 
and  lathed.     It   is   especially  recom- 


CONSTRUCTION  OF  BRICK  WALLS.  371 


mended  for  houses  that  are  to  be  plastered  on  the  outside.  At 
prevailing  prices  (1907)  it  costs  but  little  more  than  wood  con- 
struction and  less  than  brick-cased  or  veneered  construction. 

Facing-brick  may  be  used  on  the  outside  if  both  parts  are  laid  in 
cement  mortar. 

Nearly  all  building  regulations  require  that  at  least  the  same  quan- 
tity of  bricks  shall  be  used  in  the  construction  of  hollow  walls  as 
would  be  used  if  the  walls  were  built  solid ;  and  many  of  them 
require  that  both  portions  of  the  walls  shall  be  at  least  8  inches  thick, 
if  they  are  used  as  bearing  walls. 

For  heavy  buildings,  with  steel  floor  joists  and  girders,  it  is  better 
to  build  the  outer  walls  the  full  thickness  that 
vyould  be  required  in  the  case  of  single  walls, 
and  to'  make  the  inner  walls  only  4  inches 
thick,  to  serve  merely  as  a  furring  and  to 
receive  the  plaster.  Where  fire-proof  arches 
are  used  for  the  floors,  these  inner  walls 
might  without  injury  rest  on  the  floor  arches. 

366.  BONDING  OF  HOLLOW  W^ALLS. 
— To  secure  proper  strength  in  these  walls  it 
is  necessary  that  the  two  portions  shall  be 
well  bonded  together,  so  that  neither  will 
buckle  nor  get  out  of  plumb.  Until  within  a 
few  years  this  bonding  was  usually  accom- 
plished by  placing  brick  headers  across  .the 
air-spaces  with  the  ends  built  a  short  distance 
into  the  two  portions  of  the  walls,  as  shown 

Fig.  216. — Bonds  and  Ties  at  a,  Fig.  216. 
for  Brick  Hollow  W  alls. 

Brick  bonding,  however,  neutralizes  much 
of  the  benefit  gained  by  an  air-space,  as  it  permits  ^the  passage  of 
moisture  through  walls  wherever  they  are  bonded.  The  moisture 
not  only  passes  through  the  bond  bricks,  but  also  through  the  mor- 
tar droppings  that  invariably  collect  upon  them. 

The  best  method  of  bonding,  and  the  only  one  which  retains  the 
full  benefits  of  an  air-space,  is  the  one  using  metal  ties  provided  with 
a  drip  in  the  middle.  Any  one  of  the  metal  ties  shown  in  Fig.  216 
may  be  used.  That  shown  at  h  is  the  ''Morse"  tie,  which  is  made 
of  different  sizes  of  galvanized-steel  wire  and  which  varies  from  7 


3/2 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


to  1 6  inches  in  length.  The  other  ties  are  not  patented,  and  may  be 
made  by  any  blacksmith. 

The  one  shown  at  e  is  probably  the  best  shape  where  both  walls 
are  8  inches  thick,  as  it  takes  a  firm  hold  on  the  walls  and  is  also 
much  stiffer  than  the  wire  ties.  The  iron  ties  should  be  either 
galvanized  or  dipped  in  hot  asphalt  or  coal-tar. 

Wire  ties  are  probably  best  for  2-inch  air-spaces,  as  they  stop  no 
mortar  droppings  and  accommodate  themselves  to  slight  settlements 
without  injury  to  either  wall.  In  wider  spacings  greater  stiffness 
is  advisable  and  plate-iron  ties  should  be  used,  although  the  same 
result  might  be  attained  by  using  wire  ties  at  more  frequent  inter- 
vals. 

Galvanized  wire  and  sheet-metal  ties  are  manufactured  in  great 
variety  for  use  in  solid  walls,  hollow  walls  and  brick-cased  or 
veneered  walls.  It  should  be  noted  that  in  hollow  walls  mortar 
droppings  will  pile  up  on  any  ties  which  present  horizontal  flat 
surfaces. 

If  ties  of  any  of  the  shapes  shown  at  b,  c  or  d  are  used  they 
should  be  spaced  every  24  inches  in  every  fourth  course.  The  tie  e, 
being  stronger,  need  be  used  in  every  eighth  course  only. 

367.  CONSTRUCTION  AROUND  OPENINGS  IN  HOL- 
LOW WALLS. — Wherever  door  or  window  openings  occur  in 
hollow  walls  it  is  necessary  to  build  the  walls  solid  for  8  inches  at 
each  side  of  the  openings,  and  also  to  carry  the  relieving-arches 
entirely  through  the  walls.  It  is  almost  impossible  to  prevent  some 
moisture  from  passing  through  the  walls  at  these  points ;  but  much 
may  be  done  by  covering  the  tops  of  the  relieving-arches  with  hot 
tar  and  laying  the  connecting  brickwork  in  cement  mortar.  The 
tops  of  the  relieving-arches  are  obviously  the  most  vulnerable  points, 
and  should  be  protected  in  some  way  and  kept  as  free  as  possible 
from  mortar  droppings. 

368.  VENTILATION  OF  AIR-SPACES  IN  HOLLOW 
WALLS. — There  seems  to  be  some  difference  of  opinion  as  to 
whether  or  not  the  air-spaces  should  be  connected  with  the  outer  air. 
American  writers,  however,  appear  to  be  generally  of  the  opinion 
that  the  air-spaces  should  be  ventilated  to  carry  off  the  moisture 
that  collects  on  the  inside  of  the  outer  portion  of  the  walls. 

I  It  is  recommended  that  the  bottoms  of  the  air-spaces  be  ven- 
tilated through  openings  into  the  cellar,  and  that  openings  be  left 
iin  the  inner  portions  of  the  walls  just  under  the  copings  of  parapet 


CONSTRUCTION  OF  BRICK  WALLS.  373 


walls,  or  above  the  attic  floor  joists  if  the  walls  are  covered  by  the 
roof.  If  the  air-spaces  cannot  be  ventilated  into  the  attic,  then  ven- 
tilation flues  should  be  carried  up  and  topped  out  like  chimneys,  or 
built  in  connection  with  chimneys.  It  is  also  recommended  that 
U-shaped  drain  tile  be  laid  at  the  bottoms  of  the  air-spaces  to  col- 
lect any  moisture  that  may  run  down  the  outer  walls. 

369. '  HOLLOW  BRICK  WALLS  WITH  BRICK  WITHES. 
— Brick  walls  are  sometimes  built  with  4-inch  inner  and  outer 


Fig.  217. — Brick  Hollow-wall  Construction.     Congress  Hall,  Saratoga,  N.  Y. 


facings  connected  with  solid  brick  withes,  as  shown  in  Fig.  217,  the 
air-spaces  being  made  4,  8  or  12  inches,  according  to  the  height  and 
character  of  the  buildings.  Congress  Hall,  Saratoga,  N.  Y.,  a  por- 
tion of  which  is  seven  stories  high,  was  built  in  the  manner  shown 
'in  Fig.  217,  and  stood  successfully.  If  such  walls  are  built  with  the 
best  kind  of  common  bricks,  and  if  the  workmanship  is  perfect, 
they  should  have  ample  strength  for  any  ordinary  three  or  four- 
story  building,  and  would  certainly  be  more  stable  and  conduct  less 
heat  and  moisture  out  of  and  into  the  building  than  in  the  case  of 
solid  walls  containing  one-half  more  bricks.  With  such  poor 
bricks  and  workmanship  as  are  commonly  found  in  maily  parts  of 
this  country,  however,  walls  built  in  this  way  should  never  be  used 


374 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


for  any  building  larger  than  an  ordinary  two-story  dwelling.  Theo- 
retically, the  insides  of  the  walls  opposite  the  withes  would  be 
subject  to  dampness,  but  of  course  not  to  so  great  an  extent  as  in 
the  solid  walls. 

For  two-story  dwellings  these  walls,  if  well  constructed,  and  if 
the  withes  are  securely  bonded  to  the  facings,  should  make  much 
healthier  and  more  comfortable  buildings  than  those  built  with  solid 
walls. 

There  are  several  forms  of  plaster-blocks  and  plaster  or  stucco- 
boards  which  may  be  applied  with  excellent  results  to  the  inside 
of  brick  walls,  to  form  air-spaces.  As  plaster  of  Paris  is  very 
absorbent,  care  must  be  taken  to  prevent  any  contact  with  the 
brickwork.  The  Rutty  metal  non-furring  plugs  may  be  set  where 
wanted  in  the  joints  when  the  bricks  are  laid.  The  faces  of  these 
plugs  stand  ^  of  an  inch  from  the  brickwork.  Plaster  blocks  may 
be  tied  to  nails  driven  into  these  plugs,  and  for  plaster-board,  strips 
may  be  nailed  to  the  plugs  for  a  nailing.  Either  method  is  a  great 
advance  over  ordinary  wood  furrings  and  laths. 

370.  FURRIXG-BLOCKS  FOR  BRICK  WALLS.— For  office 
buildings  furring-blocks  designed  for  that  especial  purpose  are  often 
used  for  lining  or  furring  the  external  walls,  and  sometimes  hollow 
bricks  are  used  for  the  inner  4  inches  of  solid  walls ;  but  the  latter 
have  not  proved  a  success  in  excluding  moisture.    The  objection  to 

.  any  kind  of  furring  and  to  hollow  bricks  is  that  there  must  neces-  * 
sarily  be  some  connection  between  the  material  of  the  lining  or 
furring  and  the  walls  themselves,  and  this  connection  allows  the 
passage  of  heat  and  moisture. 

371.  BRICK-VENEER  CONSTRUCTION.— It  is  quite  com. 
mon  in  many  sections  of  the  country  to  build  dwellings,  and  even 
three  and  four-story  buildings,  with  outer  walls  of  frame  con- 
struction veneered  with  4-inch  facings  of  brick.  Buildings  built  in 
this  way  have  the  same  appearance,  both  outside  and  inside,  as  if 
the  walls  were  built  entirely  of  brick. 

Where  lumber  is  cheap  and  brickwork  comparatively  dear,  this 
method  of  construction  possesses  some  advantages,  although  it  is 
not  generally  approved  by  architects;  and  it  should  be  used  only 
where  hollow  brick  walls  cannot  be  afforded.  The  advantages 
possessed  by  brick-veneered  frame  walls  over  soHd  brick  walls  are 
the  lower  cost,  and  the  air-spaces,  which  latter  prevent  any  pos- 


COXSTRUCTIOX  OF  BRICK  WALLS. 


375 


sibility  of  the  passage  of  moisture,  and  also  make  the  houses  much 
warmer  in  winter  and  cooler  in  summer. 

About  the  only  advantage  that  it  possesses  over  a  method  result-  • 
ing  in  well-built  frame  buildings  is  that  it  reduces  the  insurance 
rate,  as  the  veneer  offers  some  protection  from  fires  starting  in 
adjoining  buildings.  Veneered  buildings,  however,  are  not  nearly 
as  free  from  danger  from  fire  as  brick  buildings  are,  and  they  would 
probably  be  destroyed  by  fire  on  the  inside  about  as  rapidly  as 
though  the  frame  were  covered  with  siding  or  shingles. 

The  only  differences  in  the  planning  of  a  veneered  building  from 
that  of  a  frame  building  are  that  in  the  former  the  walls  are  about 


5  inches  thicker  and  the  foundations  project  sufficiently  beyond  the 
frame  to  support  the  veneer.  The  elevations  are  drawn  the  same 
as  for  a  building  with  solid  brick  walls. 

The  wooden  frame  should  be  constructed  in  the  best  manner,  with 
at  least  4  by  6-inch  sills,  4  by  8-inch  posts,  4  by  6-inch  girts  and  4  by 
4-inch  plates,  and  should  be  well  braced  at  the  angles.  After  the 
frame  is  up  it  should  be  sheathed  diagonally  and  then  covered  with 
tarred  felt. 

It  is  also  very  important  that,  the  framing  timber  should  be  as 
dry  as  possible,  and  particularly  so  for  the  sills  and  girts.  The 
frame  must  also  be  perfectly  plumb  and  straight. 

The  veneer  is  usually  laid  with  pressed  or  face-bricks,  with  plumb 
bond,  which  should  be  tied  to  the  wooden  walls  with  metal  ties. 
Ties  similar  to  the  Morse  ties,  shown  at  a,  Fig.  218,  are  probably  the 
best  for  this  purpose,  although  the  author  has  used  ties  of  the  form 
shown  at  b  with  very  satisfactory  results.  The  ties  should  be  placed 
on  every  other  brick  in  every  fifth  course. 


Fig.  218. — Brick-veneer  Construction.     Metal  Ties. 


376 


BUILDING  CONSTRUCTION.        (Cii.  VII) 


In  laying  out  the  walls  on  the  floor  plans  6  inches  should  be 
allowed  from  the  outside  of  the  studding  to  the  outside  face  of  the 
brick  walls.  This  gives  an  air-space  of  about  i  inch  between  the 
bricks  and  sheathing  and  avoids  chipping  the  bricks  where  the 
wooden  walls  are  a  little  full.  It  is  a  good  idea  to  build  2-inch 
U-shaped  drain  tiles  in  the  foundation  walls  under  the  air-spaces 
to  collect  any  moisture  that  may  penetrate  the  veneer.  The  air- 
spaces should  also  be  ventilated  at  the  bottom  through  2-inch  drain 
tiles,  as  shown  in  Fig.  219. 


The  top  of  the  brickwork  generally  terminates  under  the  eaves  or 
gable  finish.  If  the  building  has  a  flat  roof,  with  parapet  walls,  the 
latter  should  be  coped  with  either  copper  or  galvanized-iron  and 
tinned  on  the  back  down  to  the  flashing. 

Fig.  219  shows  a  partial  section  through  the  foundation  and  a 
portion  of  the  first-story  wall  of  a  veneered  dwelling  to  illustrate 
the  construction  described  above. 

Fig.  220  shows  a  section  through  a  brick-veneered  wall,  with 


.f. 


Fig.  219. — Common  Type  of  Brick-veneered  Construction. 


CONSTRUCTION  OF  BRICK  WALLS. 


OtCTlOAf 


t)CAueL 


Fig.  220. — Sections  Through  Brick-veneered  Wall. 


some  variations  in  de- 
tails of  construction 
from  those  shown  in 
the  preceding  figures ; 
and  the  following  is 
a  brief  description  of 
the  construction 
shown  and  a  mention 
of  the  claims  made 
for  it  by  its  advocates 
in  the  Middle  West 
districts  of  the  coun- 
try. Stone  veneer  as 
compared  with  brick 
veneer  is  also  men- 
tioned. 

In  the  Middle  West 
both  brick  and  stone 
veneer  construction  is 
now  (1908)  regularly 
used,  especially  in  the 
first  story.  This  story, 
up  to  the  tops  of  the 
first-story  windows,  is 
veneered  with  briok- 
work  or  with  rough 
field-stones.  The  sec- 
ond story  is  covered 
with  siding  or 
shingles.  The  cost  of 
such  veneered  houses, 
at  the  present  time,  is 
very  little  higher  in 
these  districts  than 
that  of  houses  built 
with  solid  brick  walls. 
As  shown  in  this  sec- 
tion, the  walls  are 
generally  10^  or  11 


378 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


inches  thick,  allowing  4^  inches  for  the  brick  veneer,  i  inch  fpr 
the  air-space  and  paper,  of  an  inch  for  the  sheathing,  35/^  inches 
for  the  studs  and  ^  of  an  inch  for  the  plaster-board,  sheathing- 
lath  or  lath  and  plaster. 

Any  water  absorbed  by  the  brickwork  runs  down  the  inside  face 
to  the  copper  flashing,  out  through  occasional  holes  cut  in  the  lower 
bricks,  down  the  face  of  the  water-table  and  to  the  ground  from  the 
drip.  Bricks  similarly  perforated  and  placed  at  the  top  of  the  wall 
act  as  ventilators  for  the  air-space. 

The  veneer  is  tied  to  the  sheathing  by  metal  ties  tacked  to  the 
latter  and  imbedded  in  the  mortar  joints. 


Fig.  221. — Detail  of  Bay-window  in  Brick-veneered  Wall. 


In  order  to  imitate  special  brick  bonds,  half  bricks  are  sometimes 
used  to  represent  headers. 

When  the  stone  veneer'  is  used  there  is  a  variation  of  the  con- 
struction to  effect  the  bonding  of  the  stonework.  When  rough 
field-stones  are  employed  long  bond-stones  are  run  in  between  the 
studs  occasionally,  and  plaster-board  or  sheathing-lath  substituted 


MISCELLANEOUS  DETAILS.  379 


for  the  sheathing,  and  put  on  the  inside  of  the  studs.  Metal  ties 
are  used  in  this  construction  also. 

Fig.  221  shows  the  details  of  a  bay-window  in  a  brick-veneered 
wall.  The  mullions  are  of  brick,  and  the  window  frames  made  for 
double-hung  sash.  The  bricks  for  the  mullion  angles  are  ground 
rather  than  clipped.  In  this  construction  there  is  ample  room  for 
the  weight-boxes.  \ 

Fig.  222  shows  the  details  of  a  wooden  bay  in  a  brick  wall,  the 


Fig.  222. — Detail  of  Wooden  Bay  in  Brick  Wall. 


wall  being  in  this  illustration  solid.  Whether  the  walls  are' solid  or 
veneered,  there  is  often  difficulty  met  with  in  getting  room  enough 
for  the  weights  in  the  boxes  when  the  bay  mullions  are  of  wood ;  and 
either  the  widths  of  the  mullions  have  to  be  increased  or  special- 
shaped  weights  of  greater  lengths  used.  With  casement  window 
sash  or  brick  mullions  these  difficulties  disappear. 

4.    MISCELLANEOUS  DETAILS  IN  BRICKWORK. 

372.    BRICK  ARCHES.^^— Brick  arches  are  generally  used  for 


*  For  a  discussion  of  the  stability  of  arches,  reference  may  be  made  to  the  "Archi- 
tect's and  Builder's  Pocket-Book."    Frank  E.  Kidder. 


38o 


BUILDING  CONSTRUCTION.         (Ch.  VII) 


spanning  the  openings  in  brick  walls,  and  where  there  is  sufficient 
height  for  an  arch  it  forms  the  most  durable  support  for  a  wall 
above.  The  arches  should  be  laid  with  great  care  and  with  full 
joints,  and  all  having  a  span  of  over  lo  feet  should  be  laid  in  strong 
cement  mortar.  It  is  indeed  much  safer  to  lay  all  brick  arches  in 
cement  mortar. 

Gauged  Arches. — When  arches  are  built  of  common  bricks  the 
latter  are  laid  close  together  on  the  inner  edge,  with  wedge-shaped 
joints,  as  shown  in  Fig.  229 ;  but  when  built  of  face-br'cks  the  arch 
rim.  is  laid  out  on  a  floor  and  each  brick  is  cut  and  rubbed  to  fit 
exactly  the  place  chosen  for  it,  so  that  the  radial  joints  are  of  the 
same  thickness  throughout.    Such  work  is  called  "gauged  work." 

Bond  in  Brick  Arches. — The  only  detail  requiring  especial  men- 
tion in  connection  with  brick  arches  is  the  bond.    When  gauged 


Fig.  223. — Bonded  Gauged  Brick  Arch.  Fig.  224. — Rowlock  Brick  Arch. 

arches  are  used  the  bricks  are  generally  bonded  on  the  face  of  the 
arch  to  correspond  with  the  face  of  the  wall,  as  shown  in  Fig.  223. 
Such  an  arch  is  called  a  ''bonded  arch.''  Bonded  gauged  work 
makes  the  neatest  and  strongest  work,  but  it  is  too  expensive  to  be 
used  in  common  brick  arches. 

Arches  of  common  bricks  are  generally  built  in  concentric  rings, 
either  constructed  so  that  they  have  no  connection  with  each  other, 
except  that  resulting  from  the  tenacity  of  the  mortar,  or  else  bonded 
every  few  feet  with  bonding  courses  built  in  at  intervals  like  vous- 
soirs,  as  shown  by  the  heavy  lines  at  A,  Fig.  225.  When  the  con- 
centric rings  are  all  headers,  as  in  Fig.  224,  the  arch  is  designated  a 
*'rowlock  arch,"  and  the  bond  ''rowlock  bond" ;  and  when  the  arch  is 
built  with  bonding  courses,  as  in  Fig.  225,  the  bond  is  known  as 
"block-in-course  bond."    Segmental  arches  are  gften  built  with  con- 


MISCELLANEOUS  DETAILS. 


381 


centric  rings  of  stretchers  (Fig.  226),  which  niay  be  bonded  at 
right-angles  to  the  face  of  the  arch  by  hoop-iron.  When  the  radius 
is  over  15  feet  this  latter  construction  should  be  stronger  than  the 
rowlock  bond. 

Common  brick  arches  are  sometimes  bonded  by  introducing  head- 
ers so  as  to  unite  two  half -brick  rings  wherever  the  joints  of  two 


. — iJrick 


Arch  with  Block-in-coiirse 
J>on(l. 


Fig.  226.- 


Arch  with  Concentric  Rings  of 
Stretchci  s. 


such  rings  happen  to  coincide.  Fig.  227  shows  the  bonding  em- 
ployed in  arching  the  Vosburg  tunnel  on  the  Lehigh  Valley  Rail- 
road, the  span  being  28  feet.  The  objection  to  building  an  arch  in 
concentric  rings  is  that  each  ring  acts  nearly  or  quite  independently 

of  the  other,  and  the  least  settlement 
in  the  outer  rings  throws  the  entire 
pressure  on  the  inner  ring,  which  may 
not  be  able  to  resist  it.  When  bond- 
ing courses  are  used,  however,  they 
serve  to  tie  the  rings  together  and  to 
distribute  the  pressure  between  them, 
so  that  the  above  objection  is  over- 
come. For  arches  of  wide  span,  or 
for  those  heavily  loaded,  some  form 
of  block-in-course  bond  should  be 
used.  Hoop-iron  is  often  built  into 
arch-rings  parallel  to  the  soffit,  and  is 
also  often  worked  into  the  radial 
joints  to  unite  the  different  rings. 
The  stability  of  an  arch  may  be  greatly  increased  by  its  use. 

Skewbacks  for  Brick  Arches. — In  building  brick  arches  of  large 
span  it  is  important  to  have  solid  bearings  for  the  arches  to  spring 


Fig.  227. — Brick  Arch  over  \'osburg 
Tunnel,  Lehigh  Valley  Railroad. 


382 


BUILDING  CONSTRUCTION.         (Ch.  VII) 


from.  Such  bearings  may  be  best  obtained  by  using  stone  skew- 
backs,  as  shown  in  Figs.  226  and  227.  The  stones  should  be  cut  so 
as  to  bond  into  the  brickwork  of  the  piers,  and  the  springing  sur- 
faces should  be  cut  to  true  planes,  radiating  from  the  center  from 
which  the  arch  is  struck.  The  skewbacks  should  always  be  bedded 
in  cement  mortar. 

Flat  Arches  of  Brick. — Flat  arches  are  often  built  over  door  or 
w^indow  openings  in  external  walls  for  convenience  or  architectural 
effect.  Such  arches,  if  built  with  perfectly  level  soffits,  almost 
always  settle  a  little,  and  it  is  better  to  give  a  slight  curve  to  the 
soffits,  as  in  Fig.  228,  or  else  to  support  the  soffits  of  the  arches  on 
angle-bars,  the  vertical  flanges  of  the  bars  being  concealed  behind 
the  arch. 


Brick  Relicviug-archcs. — The  portion  of  a  wall  back  of  a  face- 
brick  arch  or  stone  lintel  over  a  door  or  window  opening  should  be 


Fig.  228. — Brick  Flat  Arch  with  Curved  P"ig.  229. — Brick  Relieving-arch. 

Soffit. 


supported  by  a  rough  brick  arch,  as  shown  in  Fig.  229.  A  wooden 
lintel  is  first  put  across  the  opening,  and  on  this  a  brick  core  or 
center  is  built  on  which  to  turn  the  arch.  Sometimes  arched  wooden 
lintels  are  used  and  the  arch  turned  on  them.  In  the  case  of 
plastered  walls  without  furring,  the  method  shown  in  the  figure  is 
the  best,  as  there  is  less  woodwork.  The  wood  lintel  should  have  a 
bearing  on  the  wall  of  not  more  than  4  inches,  and  the  arch  should 
spring  from  beyond  the  end  of  the  lintel,  as  at  A,  and  not  as  at  B, 
as  in  the  latter  method  the  arch  is  afifected  by  the  shrinkage  of  the 
lintel. 

373.  BRICK  VAULTS. — Brick  vaults  are  usually  constructed 
in  the  same  way  as  common  brick  arches,  except  that  the  bricks 
should  be  bonded  lengthwise  of  the  vault. 

Cross  vaults,  or  groined  vaults,  are  generally  supported  at  the 
intersections  by  diagonal  arches  of  the  proper  curvature,  built  so 
as  to  drop  from  8  or  12  inches  below  the  soffits  of  the  vaults. 


MISCELLANEOUS  DETAILS. 


383 


Vaults  may  be  economically  constructed  by  a  combination  of 
brickwork  and  concrete,  or  even  entirely  of  concrete.  When  built 
entirely  of  concrete,  however,  very  strong  centers  are  required. 

Fig.  230*  shows  a  method  of  constructing  vaults  much  used  by 
the  ancient  Romans.  A  light  temporary  center  of  wood  was  first 
put  in  place,  and  on  this  light  brick  arches  were  built  to  form  a 
framework  for  supporting  the  weight  of  the  vault  until  set.  These 
brick  arches  were  called  ''armatures,"  and  as  they  became  the  real 
support  of  the  vault  only  very  light  wooden  centers  were  required. 


After  the  armatures  wxre  built  the  spaces  between  them  were  filled 
with  rough  masonry  or  concrete,  as  shown  in  Fig.  231.'^' 

374.  BRICK  CHIMNEYS. t — In  planning  a  brick  chimney  the 
principal  constructive  details  to  be  considered  are  the  number, 
arrangement  and  size  of  the  flues  and  the  height  of  the  chimney. 
Every  fireplace  should  have  a  separate  flue  extending  to  the  top  of 
the  chimney.  Two  or  three  stoves,  however,  may  be  connected 
with  one  flue  if  it  is  of  suflicieht  size,  and  the  kitchen  range  may 
be  connected  with  the  furnace-flue  without  bad  results,  and  often 
the  draught  of  the  furnace  will  be  benefited  thereby.  For  ordinary 
stoves  and  for  a  small  furnace  an  8  by  8  inch  or  a  9  by  9  inch  flue, 
depending  upon  the  way  the  bricks  are  laid  and  bonded,  is  sufli- 


*  Figs.  230  and  231  are  taken  from  The  Brichhnilder  by  permission, 
t  Suitable  sizes  for  flues  for  house  heaters  are  given  in  tables  in  the  "Architect's 
and  Builder's  Pocket-Book."    Frank  E.  Kidder. 


334 


BUILDING  CONSTRUCTION.        (Ch.  VII) 


(ciently  large  if  built  so  that  it  is  smooth  on  the  inside;  but  it  is 
generally  better  to  make  furnace-flues  8  by  12  inches  or  9  by  13 
inches  and  the  fireplace-flues,  also,  the  same  size,  except  those  for 
very  small  grates.  .  ^ 

The  best  smoke-flue  is  one  built  of  bricks  and  lined  with  fire- 
clay tiles,  or  else  one  made  of  a  galvanized-iron  pipe  supported 
in  the  middle  of  a  large  brick  flue.  When  the  latter  arrangement 
is  used  the  space  surrounding  the  smoke-pipe  may  be  used  for 
ventilating  the  adjoining  rooms  by  simply  putting  registers  in  the 
walls  of  the  flue. 

When  galvanized-iron  smoke-pipes  are  used  the  metal  should  be 


Fig.  231. — Roman  Method  of  Brick-and-concrete  \'ault  Construction. 


at  least  No.  20  gauge,  and  No.  16  gauge  for  boiler-flues.  Even 
then  the  pipes  are  liable  to  be  eaten  away  by  rust  or  acids  within 
ten  or  twelve  years.  Fire-clay  flue  lining,  on  the  other  hand,  is 
imperishable. 

Smoke-flues  are  sometimes  made  only  4  inches  wide.  Such 
flues  may  work  satisfactorily  at  first,  but  they  soon  get  clogged 
with  soot  and  fail  to  draw  well,  and  should  never  be  used  unless 
it  is  impracticable  to  make  the  width  greater. 

Flues  smoke  or  draw  poorly  oftener  on  account  of  the  insufli- 
cient  height  of  the  chimney  than  from  any  other  cause.  A  chimney 
should  always  extend  a  little  above  the  highest  point  of  a  building 
or  of  buildings  adjacent  to  it,  as  otherwise  eddies  formed  by  the 
wind  may  cause  downward  draughts  in  the  flues,  making  them 


MISCELLANEOUS  DETAILS. 


385 


smoke.  If  it  is  impracticable  to  carry  a  chimney  above  the  highest 
point  of  a  roof,  it  should  be  topped  out  with  a  hood,  open  on  two 
sides,  the  sides  parallel  to  the  roof  being  closed.  The  walls  and  the 
zvithcs,  or  partitions,  of  a  chimney  should  be  built  with  great  care, 
the  joints  carefully  filled  with  mortar  and  when  there  is  no  lining 

the  joints  should  be  struck  and  the 
I  ft  ■  I  inside  surfaces  made  as  smooth  as 

J  I  I  L^g''^'^f  possible. 

I  I  Specifications    sometimes    call^  for 

H|  I  I  |H   .  flues  plastered  smoothly  on  the  inside 

I  I  with  Portland  cement,  both  to  prevent 

mm  J  &  sparks  from  passing  through  the  walls 

^  ^  and  to  increase  the  draught ;  and  in 

England  chimneys  were  formerly 
plastered  with  a  mixture  of  cowdung 
and  lime  mortar,  which  was  called 
"pargetting."  Portland  cement  is  not 
affected  by  heat  and  is  the  best ' 
material  for  this  purpose. 

Many  building  laws,  Uowever,  for- 
bid the  plastering  of  the  fliie  surfaces 
on  account  of  the  tendency  of  the 
plaster  to  fall  ofif  in  places,  carryings 
with  it  pieces  of  mortar  from  the 
joints  of  the  brickwork  and  increasing 
the  chances  of  sparks  passing  through. 

In  building  a  chimney  more  or  less 
mortar  and  also  pieces  of  brick  are 
sure  to  drop  into  the  flues,  and  a  hole 
should  be  left  at  the  bottom  of  each 
one,  with  a  board  stuck  in  on  a  slant, 
to  catch  the  falling  mortar.  After  the 
chimney  is  topped  out  the  board  and 
mortar  should  be  removed  and  the 
hole  bricked  up.  If  there  are  bends  in  a  flue  openings  should  be 
left  in  the  walls  at  those  points  for  cleaning  out  any  bricks  and 
mortar  that  may  lodge  there.  The  outer  walls  of  chimneys  should 
be  8  inches  thick,  unless  flue  linings  are  used,  in  order  to  prevent 
the  smoke  from  being  chilled  too  rapidly. 


Fig.  232. — Brick  Chimney  Flues  for 
jL  iirnace  and  Fireplaces. 


MISCELLANEOUS  DETAILS. 


387 


During  the  construction  of  a  building  the  architect  or  superin- 
tendent should  be  careful  to  see  that  no  woodwork  is  placed  within 
I  inch  of  the  walls  of  any  smoke-flue,  and  that  all  flues  are  smooth 
through  their  entire  length. 

The  arrangement  of  chimney  Hues  is  ordinarily  very  simple.  Fig. 
232  shows  the  ordinary  arrangement  of  flues  in  a  chimney  con-  , 
taining  a  furnace-flue,  fireplaces  in  the  first  and  second  stories,  and 
an  ash-flue  for  the  second-story  fireplace. 

Fig.  233,  from  Part  11.  of  ''Notes  on  Building  Construction,"* 
shows  the  arrangement  of  the  flues  in  a  double  chimney,  with  fire- 
places in  five  stories. 

Radial  Block  Chimneys. — There  are  several  systems  of  con- 
structing high  factory  chimneys  by  special  forms  of  blocks,  radial 
or  otherwise.  Among  those  who  make  a  specialty  of  such  work 
are  the  Alphonse  Custodis  Chimney  Construction  Company,  New 
York;  H.  R.  Heinicke,  Inc..  New  York;  George  H.  Thirsk, 
Philadelphia. 

375.  BRICK  FIREPLACES.— r/z^-  Rough  Opening.— In  build- 
ing a  fireplace,  no  matter  how  it  is  to  be  finished,  it  is  cus- 
tomary first  to  build  a  rough  opening  in  the  chimney  from  6  to  8 
jnches  wider  than  the  intended  width  of  the  finished  opening,  and 
I  or  2  inches  higher,  drawing  in  the  bricks  above  to  form  the  flue, 
as  shown  in  Figs.  232  and  233.  The  front  wall  of  the  chimney, 
over  the  opening,  may  be  supported  by  a  segmental  arch  when  there 
are  sufficient  abutments  ;  but  when  the  side  walls  are  only  4  or  8 
inches  thick  heavy  iron  bars  should  be  used  to  support  the  brick- 
work. The  depth  of  the  rough  opening  should  be  at  least  12 
inches,  to  permit  of  an  8-inch  flue. 

When  there  are  fireplaces  the  bottom  of  the  chimney  is  usually 
built  hollow  so  as  to  form  a  receptacle  for  the  ashes  f tom  the 
grate,  as  shown  in  Fig.  234.  If  the  fireplace  is  to  be  used  fre- 
quently an  ash-pit  is  almost  a  necessity,  especially  in  residences,  and 
it  should  always  be  provided  when  practicable.  When  the  fire- 
place is  above  the  ground  floor  a  flue  can  generally  be  built  to 
connect  the  bottom  of  it  with  the  ash-pit.  In  the  chimney  shown  in 
Figs.  232  and  234  the  ash-flue  is  built  back  of  the  lower  fireplace. 
When  there  is  no  furnace-flue  the  ash-flue  can  be  carried  dovv^n  on 
one  side  of  the  lower  fireplace,  thereby  saving  4  inches  in  the  thick- 


*  Rivington's  South  Kensington  Series. 


388 


BUILDING  CONSTRUCTION.         (Ch.  VII) 


ness  of  the  chimney.  One  ash-flue  will  answer  for  several  fire- 
places. A  cast-iron  door  and  frame,  usually  about  lo  by  12  inches, 
should  be  built  in  the  bottom  of  the  ash-pit  so  that  the  ashes  can  be 
removed. 

The  ash-pit,  rough  opening  and  flues  form  the  chimney,  and  are 
all  built  at  the  same  time  by  the  brick- 
mason,  who  builds  the  trimmer  arch  also. 

The  Trimmer  Arch. — In  buildings  with 
wooden  floor  construction  each  fireplace 
hearth  is  usually  supported  by  a  "trim- 
mer arch,"  commonly  2-  feet  wide  by  the 
width  of  the  chimney  in  length,  turned 
on  a  wooden  center  from  the  chimney  to 
the  joist  header,  as  shown  in  Fig.  234. 
The  wood  center  is  put  up  by  the  car- 
penter, one  side  being  supported  by  the 
header  and  the  other  by  a  projecting 

or  by  flat 
the 


brick  course  on  the  chimney 
pieces  of  iron  driven  into 
Although  not  needed  for 
support  after  the  arch  has 
set,  the  center  is  generally 
left  in  place  to  afford  a  nail- 
ing for  the  laths  or  furring 
strips  on  the  ceiling  below. 


Sometimes  a  flagstone  is 


-Section  Through  Brick  Fireplace,  Chim- 
ney Flues  and  Ash-pit. 


hung  from  the  joists  to  sup- 
port a  hearth,  but  a  stone  generally  costs  more  than  an  arch,  and 
in  the  opinion  of  the  author  is  not  as  good,  as  the  arch  will  adjust 
itself  to  slight  settlements  in  the  chimney,  and  is  not  affected  by 
any  shrinkage  of  the  floor  joists. 

The  Finished  Fireplace. — After  a  building  is  plastered  the 
finished  fireplace  is  built,  usually  by  the  parties  furnishing  the 
material,  unless  it  is  brick,  when  the  work  may  be  done  by  any- 
skilled  brick-mason. 

At  the  present  time  the  larger  number  of  fireplaces  are  probably 
built  with  fire-brick  linings  and  tile  facings  and  hearths,  with 
wooden  mantels,  after  the  manner  shown  in  Figs.  234  and  235.  In 
building  such  a  fireplace  the  hearth  is  first  levelled  up  with  brick  or 


MISCELLANEOUS  DETAILS. 


389 


concrete,  after  which  the  hearth  and  the  ''imder-fire"  are  laid,  the 
metal  frame  at  the  edge  of  the  opening  set  up  and  the  lining  and 
the  backing  for  the  tile  facing  built.  After  this  work  is  completed 
the  tile  facing  is  set,  and  when  the  mortar  has  dried  out,  the  mantel, 
if  of  wood,  is  set  against  it.  Glazed  tiles  are  usually  employed  for 
the  hearth  and  facings,  and  they  should  always  be  set  in  rich  Port- 
land cement  mortar.  The  sides  of  the  linings  forming  the  fire-box 
should  be  bevelled  about  3  inches  to  the  foot,  and  the  back  should 
be  brought  inward  at  the  top,  as  shown,  so  that  the  opening  into 
the  flue  will  be  only  about  3  inches  wide.    The  opening  is  called  the 


Chimney  Plastered.  Chimnei)  Furred 


Fig.  235. — Sections  Through  Fireplace,  Linings,   Furrings,   Mantel,  etc. 

''throat,"  and  its  proportions  determine  in  a  great  measure  whether 
the  draught  will  be  good  or  bad. 

A  damper  should  always  be  provided  for  closing  the  throat.  The 
simplest  arrangement  is  a  piece  of  heavy  sheet-iron  with  a  ring  on 
the  edge,  as  shown  at  A,  Fig.  234.  It  may  be  operated  by  the  poker. 
A  much  better  device,  and  one  now  quite  frequently  used,  consists 
of  a  cast-iron  frame  with  a  door  which  may  be  pushed  back  to 
give  the  full  opening.  The  door  has  a  sliding  damper  also  suffi- 
cient to  let  ofif  the  gases  after  the  fire  is  well  started.  This  device 
can  be  obtained  of  most  mantel  dealers,  and  generally  insures  a 
good  draught.  A  small  cast-iron  ash-dump,  also,  should  be  placed  in 
the  bottom  of  the  fireplace  when  there  is  an  ash-pit. 

The  Grates. — There  are  a  great  many  styles  of  grates  that  may 
be  used  in  fireplaces.  In  one  such  as  has  been  just  described  the 
''club-house"  grate  is  probably  most  frequently  used  in  localities 
where  soft  coal  is  burned.  It  consists  of  a  cast-iron  grate  supported 
by  four  legs,  and  with  an  ornamental  front  about  6  inches  high. 
It  has  no  back  or  sides,  and  should  fit  close  to  the  fire-brick  lining. 
There  is  also  a  movable  front  to  close  the  opening  beneath  the  grate. 
These  grates  are  well  adapted  to  soft  coal  or  coke. 


390 


BUILDING  CONSTRUCTION. 


(Ch.  VII) 


For  fireplaces  that  are  to  be  frequently  or  steadily  used  a  narrow 
opening,  about  21  inches,  is  most  desirable,  as  wider  openings  are 
very  wasteful  of  coal. 

Fireplaces  in  which  wood  is  to  be  burned  may  have  openings  up 
to  4  feet  wide,  3-feet  openings  being  quite  common.  Wood  is  gen- 
erally burned  on  andirons. 


Fig.  236. — Details  of  a  Large  Brick-and  stone  Fireplace. 


stcTion 


For  burning  hard  coal,  especially  in  ornamental  fireplaces,  basket- 
grates,  having  open  fronts  and  solid  backs  and  ends,  are  often  used. 
They  are  made  of  various  sizes  and  may  be  used  in  any  fireplace. 

One  of  the  most  practical  devices  is  the  "portable  fireplace,"  which 
is  a  complete  cast-iron  fireplace  with  fire-box,  dampers,  shaking 
grate  and  separate  front  piece  for  summer.  It  can  be  set  in  any 
opening  of  suitable  size,  and  is  sure  to  draw  well  if  the  flue  is 
reasonably  large  and  high.     These  fireplaces  are  finished  with 


MISCELLANEOUS  DETAILS. 


ornamental  frames  about  3  inches  wide,  in  different  finishes,  and 
can  be  used  with  tile,  marble  or  brick  facings.  They  are  made  with 
20  and  24-inch  openings. 

Brick-and-stonc  Fireplaces. — Fig.  236  shows  the  details  of  a 
large  brick  fireplace  in  which  stone  is  used  for  the  hearth,  base, 
keystone,  shelf  and  brackets.  In  the  Middle  West  and  Northwest 
fireplaces  of  this  kind  are  very  common,  and  are  used  in  large  living- 
rooms  or  halls.  They  are  designed  to  burn  large  wood  logs  and 
have  openings  of  sufficient  width  and  depth  to  receive  several  at  one 
time,  and  to  receive  them  back  of  the  line  of  the  throat  to  prevent 
smoke  from  coming  out  into  the  room. 

The  throat  is  made  narrow  and  long,  with  a  shelf  above,  made 
flat  as  shown,  and  forming  the  top  of  the  throat  corbelling.  This 
shelf  extends  back  to  the  inside  face  of  the  outer  wall  so  as  to 
assist  in  preventing  down  draughts. 

The  walls  of  the  chimney  flues  are  made  not  less  than  8  inches 
thick,  unless  they  have  tile  flue-linings,  in  which  case  they  are  fre- 
quently reduced  to  4^  inches  if  the  height  permits. 

The  ash-flue  leads  to  the  ash-pit  in  the  cellar,  and  in  case  there  is  a 
fireplace  above  on  the  second  floor  connected  with  the  same  chimney, 
the  ash-flue  from  this  fireplace  also  is  carried  down  as  shown  along- 
side the  first-story  fireplace  and  into  the  same  ash-pit. 

A  large  fireplace  is  sufficient  to  amply  ventilate  a  very  large 
room,  and  even  all  the  rooms  of  an  entire  story  of  a  moderate- 
sized  house  in  which  the  communicating  doors  are  left  open. 

A  fireplace  may  be  built  also  with  pressed-brick  facings,  with 
either  a  square  or  an  arched  opening,  and  with  a  wood  mantel  set 
against  it,  the  same  as  with  tile  facings.  If  wood  is  to  be  burned, 
pressed  bricks  may  be  used  for  the  linings  also,  but  they  will  not 
stand  the  intense  heat  of  a  coal  fire.  For  the  latter  fire-bricks  should 
be  used  for  the  linings. 

Brick  and  Terra-cotta  Mantels. — Although  brick  facings  in  con- 
nection with  wooden  mantels  have  been  much  used,  the  practice 
does  not  seem  to  be  one  to  be  recommended,  either  from  a  practical 
or  decorative  standpoint.  If  brick  is  to  be  used  at  all,  it  would  seem 
better  to  make  the  entire  mantel  of  brick  or  of  brick  and  terra- 
cotta. In  fact  there  are  no  materials  which  can  be  used  with  better 
efifect  for  the  finish  about  a  fireplace  than  brick  or  terra-cotta, 
although  they  require  artistic  skill  in  the  selection  of  the  color  and 
in  their  arrangement. 


392 


BUILDING 


CONSTRUCTION. 


(Ch.  VII) 


The  great  drawback  in  the  past  in  building  brick  mantels  has  been 
the  difficulty  of  obtaining  bricks  of  suitable  color  and  accuracy  of 
form  which  could  be  adapted  to  a  satisfactory  decorative  treatment. 
This  difficulty,  however,  no  longer  exists,  as  there  are  now  several 
companies  that  make  a  specialty  of  producing  brick  mantels  of 
artistic  design.    These  arc  skilfully  designed  with  good  architectural 


Fig.    237. — Brick    and   Terra-cotta    Fireplace    Mantel.     Manufactured    by    Fiskc    &  Co. 

J.  II.  Ritchie,  Designer. 


effects,  and  all  the  parts  are  accurately  fitted,  so  that  they  can  be 
easily  put  together  by  any  skilled  brick-mason.  They  are  in  a 
variety  of  designs  and  colors,  and  can  be  varied  within  certain  limits 
of  size  to  fit  any  particular  space.  The  mantels  of  several  manu- 
facturers are  extensively  used,  and  with  very  satisfactory  results. 
In  many  of  them  the  ornamentation  is  largely  of  terra-cotta 


MISCELLANEOUS  DETAILS/ 


393 


Instead  of  molded  bricks,  and  a  special  feature  of  this  terra-cotta 
ornamentation  is  that  the  pieces  are  made  in  standard  sizes  which 
are  interchangeable.  This  feature  has  often  been  utilized  by  archi- 
tects, as  it  affords  them  an  opportunity  of  making  designs  to  suit 
their  own  individual  tastes  as  regards  the  choice  and  arrangements 
of  ornamentation,  by  bringing  together  in  any  desired  comxbination 
the  standard  interchangeable  pieces,  thus  gaining  practically  all  the 
desirable  features  of  special  designs,  with  the  additional  advantages 
of  moderate  cost  and  certainty  of  delivery. 

Figs.  237,  238,  239  and  240  illustrate  various  designs  of  brick 


Fig.  238. — Brick  and  Terra-cotta  Mantel.    Philadelphia  and  Boston  Face-brick  Co.,  Boston. 

and  terra-cotta  mantels.    Fig.  237  is  by  Fiske  &  Co.,  Boston ;  Fig. 

238  by  the  Philadelphia  and  Bo.ston  Face-brick  Co.,  Boston;  Fig. 

239  by  the  Eastern  Hydraulic-press  Brick  Co.,  Philadelphia,  and 
Fig.  240  by  Gladding,  McBean  &  Co.,  San  Francisco.  Fig.  241 
shows,  on  a  large  scale,  the  construction  details  of  the  molded 
bricks  used  in  the  arch  of  the  mantel  shown  in  Fig.  240. 

In  the  mantel  of  Fig.  237  8  by  ii/2-inch  bricks  are  used.  The 
mantel  shown  in  Fig.  239  is  a  suggestion  for  a  chimney-piece  suit- 


394 


BUILDING  CONSTRUCTION,        (Ch.  VII) 


able  for  a  club,  hotel,  railroad  station  or  other  semi-public  building. 
The  design,  even  to  the  hearth,  is  entirely  of  brickwork.  This 
chimney-piece  is  about  lo  feet  wide  and  lo  feet  6  inches  high. 
The  fire-opening  is  about  4  feet  wide  and  3  feet  5  inches  high. 

In  the  mantel  shown  in  Fig.  240  ''Roman"-shape  bricks,  8^  by 


Fig.  239. — Brick  Chimney-piece.    Eastern  Hydraulic-press  Brick  Co., 
-  Philadelphia. 


4  by  inches,  are  used,  with  ^-inch  mortar  joints.  The  following 
are  the  dififerent  dimensions  for  this  mantel : 

Feet.  Inches. 


Width  of  breast   7  8 

Height  of  mantel   4  10/^ 

Width  of  opening   4  4/i 

Length  of  hearth   7  8 

Returns  at  sides  :   i  0% 

Depth  of  fire-box   i  9 

Height  of  opening    2  9 

Width  of  hearth   2  i  ■ 

Width  of  opening  between  hobs   2  9K 


MISCELLANEOUS  DETAILS. 


395 


376.  BRICK  STAIRS. — For  building-  fire-proof  stairs  there  is 
probably  no  better  material  than  brick,  unless  it  be  Portland  cement 
concrete  in  combination  with  metal  tension  bars.  Brick  stairs  may 
easily  be  built  between  two  brick  walls  by  springing  a  segmental 


Fig.  240. — Design  for  Brick  Mantel.     Gladding,  McBean  &  Co.,  San  Francisco. 

arch  from  wall  to  wall  to  form  the  sofht  and  by  building  the  steps 
on  top  of  this  arch ;  or,  if  one  side  of  the  stairs  must  be  open,  that 
side  may  be  supported  by  a  steel  I-beam,  which  should  be  protected 
by  fire-proof  tiling.    This  is  shown  in  Fig.  242.    The  stairs  in  the 


L 


Fig.  241. — Detail  Section  and  Elevation  of  Arch  of  Mantel  Shown  in  Fig.  240. 

Pension  Building  at  Washington  were  constructed  in  this  way.  The 
treads  of  the  steps  may  be  of  hard-pressed  bricks,  or  slate  treads 
may  be  laid  on  top  of  the  bricks.  Iron  treads  are  not.  desirable,  as 
they  become  slippery. 


396  BUILDING  CONSTRUCTION.        (Ch.  VII) 

Brick  Spiral  Stairs.— Fig.  243  shows  a  brick  spiral  staircase,  of 
former  days,  in  the  House  of  Tristan,  the  Hermit,  Tours,  France. 
Fig.  244  shows  a  method  of  constructing  spiral  stairs  of  brick- 


— Details  of  Brick  Stairs,  Pension  Building,  Washington,  D.  C. 


work  commonly  employed  in  Madras,  India.  These  stairs  are  built 
without  any  centering,  and  cost  in  Madras  less  than  one-third  as 
much  as  iron  stairs.  It  would  seem  as  though  this  construction 
might  be  advantageously  employed  in  this  country  where  spiral  stairs 


MISCELLANEOUS  DETAILS. 


397 


are  to  be  built  in  fire-proof  buildings.  The  dimensions  of  a  typical 
Madras  spiral  staircase  are  about  as  follows : 

^        Diameter  of  stairs,  wall  to  wall,  inside   6  feet. 

Diameter  of  newel  in  center   i  foot. 

Headway,  from  top  of  step  to  arching  overhead,  7  feet  inches. 

Risers,  each    6  inches. 

Tread  at  wall   i  foot    2]/^  inches. 

Tread  at  newel   2)^  inches. 


Fig.   243. — Staircase,  House  of 
Tristan,    the  Hermit, 
Tours,  France. 


SECTION  ONAB. 


PLAH. 

Fig.  244. — Brick  Spiral  Stairs. 
Construction  Used  in  Madras, 
India. 


Having  determined  the  rise  and  number  of  steps  in  the  usual  way,  work 
is  commenced  by  building  up  solid  two  or  three  steps,  when  the  arch  is  then 
started  by  ordinary  terrace  bricks,  5  by  3  by  i  inch,  in  lime  mortar  (i>2  parts 
slaked  lime  to  i  of  clean  river  sand).  The  bricks  are  put  edgewise  flat  against 
one  another,  with  their  lengths  in  radii  from  the  center  of  the  stairs,  and  are 
simply  stuck  to  one  another  by  the  aid  of  the  mortar  without  any  centering. 
These  arch  bricks  are  arranged  as  shown  at  S ,  the  soffit  being  a  continuous 
incline,  as  shown  in  the  section  CD.  A  slight  rise,  about  inches,  is  given 
to  the  arch  as  shown  in  the  section. 

For  forming  the  steps  over  this  arching  ordinary  bricks  are  used,  usually 


398 


BUILDING  CONSTRUCTION. 


(Ch.  VII) 


9  by  41/2  by  3  inches,  trimmed  to  position  and  placed  on  edge  as  at  T  in  the 
plan. 

After  a  reasonable  time  for  the  mortar  to  harden,  the  work  shaald  bear  a 
load  of  300  pounds  placed  on  a  step  and  show  no  sign  of  giving.  With  gocrd 
materials  the  steps  will  bear  much  heavier  loads.— J.  M.,  in  Indian  Engi-, 
neering. 

BRICK  NOGGING.— "Noggiiig"  is  a  term  that  is  applied 
to  brickwork  filled  in  between  the  studding  of  wooden  partitions. 
Brick  nogging  is  often  employed  in  wooden  partitions  of  dwellings 
and  tenement-houses  to  obstruct  the  passage  of  fire,  sound  and 
vermin.  As  no  particular  weight  comes  upon  the  bricks,  and  as 
they  are  not  exposed  to  moisture,  the  cheapest  kind  of  bricks  may 
be  used  for  this  purpose.  The  bricks  should  .be  laid  in  mortar,  as 
in  4- inch  walls.  If  a  partition  is  to  be  lathed  W'ith  wooden  laths 
it  is  necessary  that  the  width  of  the  bricks  shall  be  not  quite  equal  to 
that  of  the  studding,  in  order  to  allow  for  the  clinch  of  the  plaster. 
When  3^-inch  studding  is  used  it  will  be  necessary  either  to  clip 
the  bricks  or  to  lay  them  on  edge.  ' 

When  the  studding  of  a  partition  rests  on  the  cap  of  the  partition 
below,  it  is  an  excellent  idea  to  fill  in  the  space  between  the  floor  and 
the  ceiling  below  with  nogging  to  prevent  the  passage  of  fire  and 
mice ;  and  two  courses  of  bricks  laid  on  horizontal  bridging  is  also  a 
good  method  of  preventing  fire  or  vermin  from  ascending  in  a  par- 
tition. 

378.  CLEANING  DOWN  BRICKWORK.— Soon  after  the 
walls  are  completed  all  pressed  or  face-brick  should  be  washed  and 
scrubbed  with  muriatic  acid  and  water,  using  either  scrubbing- 
brushes  or  corn  brooms.  The  scrubbing  should  be  continued  until 
all  stains  are  removed.  At  the  same  time  all  open  joints  under 
window  sills  and  in  the  stone  and  terra-cotta  work  should  be 
pointed,  so  that  when  the  cleaning  down  is  completed  the  entire 
walls  will  be  in  perfect  condition. 

379.  EFFLORESCENCE  ON  BRICKWORK.— A  white 
efflorescence  often  appears  on  walls  after  they  have  been  soaked 
with  water.  There  are  at  least  three  different  substances  that  may 
cause  this  efflorescence.  Of  these  carbonate  of  soda  appears  most 
frequently  on  new  walls,  and  is  due  to  the  action  of  the  lime  in  the 
mortar  upon  the  silicate  of  soda  in  the  bricks.  Silicate  of  soda  sel- 
dom occurs  in  bricks  unless  a  salt  clay  is  used. 

The  only  other  white  efflorescence  of  importance  is  composed 
chiefly  of  sulphate  of  magnesia,  due  to  pyrites  in  the  clay ;  and  this, 


MISCELLANEOUS  DETAILS. 


399 


when  burned,  gives  rise  to  sulphuric  acid,  which  unites  with  the 
magnesia  in  the  mortar. 

The  above  are  the  resuhs  of  investigations  made  by  Mr.  Samuel 
Cabot,  chemist.    The  conclusions  he  arrived  at  are  these : 

(1)  The  efflorescence  is  never  due  to  the  bricks  alone,  and  sel- 
dom due  to  the  mortar  alone. 

(2)  To  avoid  efflorescence,  the  bricks  should  be  rendered  imper- 
vious with  some  preservative  having  the  property  of  keeping  salts 
from  exuding.  Linseed-oil  cannot  fill  the  requirements,  as  it  is 
injured  by  the  mortar. 

In  order  to  make  brick  walls  impervious,  howxver,  it  is  necessary^ 
before  coating  them,  to  minutely  examine  all  joints  and  fill  all  holes. 
It  is  the  opinion  of  the  writer  that  if  reasonably  hard  bricks  are 
used  for  facings,  the  joints  closely  examined  and  filled  and  all  brick 
projections  and  exposed  tops  waterproofed  and  provided  with 
drips,  but  little  efflorescence  will  appear. 

380.  DAMP-PROOFING  BRICK  WALLS.— All  brick  and 
stone  walls  absorb  more  or  less  moisture,  and  a  wall  12  inches  thick 
.may  sometimes  be  soaked  through  in  a  driving  rainstorm.  In  the 
dry  climates  of  Colorado,  Arizona  and  New  Mexico  such  storms 
rarely  occur,  and  it  is  customary  in  those  localities  to  plaster  directly 
on  the  inside  of  the  walls.  In  nearly  all  other  parts  of  the  country, 
however,  it  is  desirable,  for  the  sake  of  health  and  for  economy  in 
heating,  even  if  not  absolutely  necessary,  either  to  fur  or  strip  the 
inside  of  solid  walls  with  i  by  2  inch  strips,  or  to  render  the  w^alls 
damp-proof,  either  by  a  coating  of  some  kind  applied  to  the  outside 
of  the  walls,  or  by  building  the  walls  hollow.  Furring  the  walls 
with  wooden  strips  and  then  lathing  on  them  prevents  the  moisture 
from  coming  through  the  plastering,  but  it  does  not  prevent  the 
walls  themselves  from  becoming  soaked,  thereby  necessitating  more 
heat  to  warm  a  building  and  tending  to  gradually  destroy  the 
walls.  A  hollow  wall,  when  properly  built,  is  probably  the  best 
device  for  preventing  the  passage  of  moisture  and  also  of  heat ;  but 
in  most  cases  it  is  also  the  most  expensive  method. 

Brickwork  may  be  rendered  impervious  to  moisture  either  by 
painting  the  outside  of  the  walls  with  white  lead  and  oil  or  by  coat- 
ing the  walls  with  preparations  of  paraffine,  or  by  some  of  the 
patented  waterproofing  processes.  The  preparations  containing 
paraffine  are  usually  applied  hot,  and  the  walls  also  are  heated  by  a 
portable  heater  previous  to  the  application.    They  give  fairly  good 


400 


BUILDING  COXSTRUCTION.         (Ch.  VII) 


results,  but  are  quite  expensive,  owing  to  the  time  and  labor  required 
for  their  application. 

Sylvester's  process,  which  consists  in  covering  the  surfaces  of  the 
walls  with  two  washes  or  solutions,  one  composed  of  Castile  soap 
and  water  and  one  of  alum  and  water,  has  been  used  w^ith  much 
success  for  this  purpose.  A  full  description  of  the  successful  appli- 
cation of  this  process  to  the  walls  of  the  gate-houses  of  the  Croton 
Reservoir  in  Central  Park,  New  York,  is  given  by  Ira  O.  Baker  in 
his  "Treatise  on  Masonry  Construction." 

All  of  these  preparations  change  somewhat  the  color  and  grain  of 
the  bricks,  and  are  generally  looked  upon  as  detracting  from  the 
appearance  of  the  building. 

Boiled  linseed-oil  is  often  applied  to  brick  walls,  and  two  coats  will 
prevent  the  absorption  of  moisture  for  from  one  to  three  years.  The 
oil  does  not  greatly  change  the  color  of  the  bricks,  and  generally 
improves  the  appearance  of  a  wall  which  has  become  stained  or  dis- 
colored in  any  way. 

Common  white-lead-and-oil  paint  is  probably  the  best  material  for 
damp-proofing  external  walls  above  ground,  but  it  changes  entirely 
the  appearance  of  the  building.  Painting  of  new  work  should  be 
deferred  until  the  walls  have  been  finished  at  least  three  months,  and 
three  coats  should  be  given  at  first ;  after  this  one  coat  applied  every 
four  or  five  years  will  answer.  A  preparation  known  as  "Duresco" 
has  been  used  for  damp-proofing  with  very  satisfactory  results.  It 
has  been  used  in  some  cases  for  coating  the  inside  of  the  walls 
before  the  plastering  is  applied,  to  prevent  the  moisture  penetrating 
the  plastering,  which  purpose  it  seems  to  have  successfully  accom- 
plished. 

Diiresco,  when  applied  to  common  or  soft  bricks,  not  only  renders 
them  weather-proof,  but  its  color  gives  the  permanent  appearance 
for  which  pressed  bricks  are  valued.  It  dries  with  a  hard,  uniform, 
impervious  surface  free  from  gloss,  and  does  not  flake  off  or  change 
color..  It  is  put  up  in  56-pound  kegs,  that  quantity  being  sufficient 
for  covering  1,000  square  feet  with  two  coats. 

Cabot's  Brick  Preservative  is  claimed  by  the  manufacturer  to 
form  a  thorough  waterproofing  for  brickwork  and  sandstone,  thus 
preventing  white  efflorescence,  disintegration  of  chimneys  by  frost, 
and  growth  of  fungus. 

It  does  not  change  the  natural  texture  of  the  material  to  which  it 
is  applied  and  it  leaves  no  gloss.   It  has  been  found  by  actual  experi- 


MISCELLANEOUS  DETAILS. 


ment  that  one  coat  of  this  preservative  makes  as  good  a  waterproof- 
inof  as  three  coats  of  boiled  hnseed-oil. 

The  preservative  is  manufactured  in  two  forms :  One  kind  is 
colorless,  for  use  on  any  kind  of  bricks,  to  render  them  waterproof 
and  to  prevent  efflorescence ;  and  the  other  has  red  color  added,  to 
bring  the  bricks  to  an  even  shade  without  destroying  the  texture. 

This  material  is  applied  with  a  brush  in  the  same  way  that  oil  is 
applied,  no  heat  being  necessary.  To  obtain  the  best  results,  the 
brickwork  should  first  be  washed  down  with  acid,  preferably  nitric 
acid,  to  remove  any  efflorescence  already  formed.  One  gallon  will 
cover  about  200  square  feet  on  average  rough  bricks  and  a  little 
more  on  pressed  bricks.  One  coat  is  generally  sufficient  unless  the 
bricks  are  extremely  soft  and  porous. 

To  prevent  moisture  from  penetrating  the  tops  of  brick  vaults 
built  underground,  a  coating  of  asphalt,  from  ^  to  %  of  an  inch 
thick  and  applied  at  a  temperature  of  from  360°  to  518°  Fahr., 
seems  to  give  the  best  results.  Common  coal-tar  pitch  is  often  used 
for  this  purpose,  but  is  not  as  good  as  asphalt.  If  a  vault  is  to  be 
covered  with  soil  for  vegetation,  the  top  course  of  bricks  should  be 
laid  in  hot  asphalt  in  addition  to  the  coating. 

381.  THE  CRUSHING  STRENGTH  OF  BRICKWORK.*— 
In  the  majority  of  brick  and  stone  buildings  the  crushing  strength 
of  brickwork  need  be  considered  only  in  connection  with  piers  and 
arches  and  under  bearing-plates  or  templates.  The  strength  of 
brickwork  varies  with  the  strength  of  the  individual  bricks,  the 
quality  and  composition  of  the  mortar,  the  workmanship  and  bond 
and  the  age  of  the  brickwork.  It  is  not  the  purpose  here  to  dis- 
cuss the  subject  of  the  strength  of  materials,  but  it  may  be  stated 
that  for  general  practice  the  following  safe  loads  may  be  allowed 
for  the  compressive  strength  of  brickwork  in  the  cases  above  men- 
tioned ;  For  New  England  or  similar  hard-burned  bricks,  in  lime 
mortar,  from  8  to  10  tons  per  square  foot  (112  to  138  pounds  per 
square  inch). 

For  the  same  bricks  laid  in  mortar  composed  of  natural  cement  I 
part,  and  sand  2  parts,  12  tons  per  square  foot  (166  pounds  per 
square  inch). 

For  the  same  bricks  laid  in  cement-and-lime  mortar,  i  to  3,  14 
tons  per  square  foot  (194  pounds  per  square  inch). 


*  Further  details  on  this  subject  may  be  found  in  the  "Architect's  and  Builder's 
Pocket-Book,"  by  Frank  E.  Kidder. 


402 


BUILDIXG  COXSTRUCTION. 


(Ch.  VII) 


For  the  same  bricks  laid  in  Portland  cement  and  sand  mortar,  i 
to  2,  15  tons  per  square  foot  (280  pounds  per  square  inch). 

Average  hard-burned  Western  bricks,  in  Louisville  cement  mor- 
tar, I  to  2,  10  tons  per  square  foot. 

For  the  same  bricks  laid  in  Portland  cement  mortar,  i  to  2,  12^ 
tons  per  square  foot  (175  pounds  per  square  inch). 

In  computing  the  safe  resistance  of  brickwork  from  actual  tests 
of  the  ultimate  strength  of  work  of  the  same  kind,  a  factor  of  safety 
of  at  least  10  should  be  allowed  for  piers  and  20  for  arches.  Piers 
higher  than  6  times  their  least  sectional  dimension  should  be 
increased  4  inches  in  size — that  is,  in  their  lateral  dimensions — for 
each  additional  6  feet  in  height. 

In  most  cities  the  maximum  permissible  loads  for  dif¥erent  kinds 
of  masonry  are  fixed  by  the  building  laws. 

It  should  always  be  remembered  that  the  strength  of  brick  piers 
depends  largely  upon  the  thoroughness  with  which  they  are  bonded, 
and  the  building  of  all  piers  should  be  carefully  watched  by  the 
superintendent. 

382.  MEASUREMENT  OF  BRICKWORK.— Brickwork  is 
generally  measured  by  the  one  thousand  bricks  laid  in  the  wall. 
The  usual  custom  of  brick-masons  is  to  take  the  outside  superficial 
area  of  the  wall,  the  corners  being  measured  twice,  and  multiply  it 
by  15  for  an  8  or  9-inch  wall,  by  22^  for  a  12  or  13-inch  wall  and 
by  30  for  a  16  or  18-inch  wall,  the  results  giving  the  number  of 
bricks.  These  figures  give  about  the  actual  number  of  bricks  required 
to  build  the  walls  in  the  Eastern  States,  but  in  the  Western  States, 
where  the  bricks  are  larger,  they  give  about  one-third  more  than  the 
actual  number  of  bricks  contained  in  the  walls,  and  the  price  is  regu- 
lated accordingly.  During  the  author's  experience,  in  both  the 
Eastern  and  Western  States,  he  has  never  known  any  deviation  made 
from  these  figures  by  brick-masons.  In  the  West  two  kinds  of 
measurements  are  known,  kiln  count  being  used  to  designate  the 
actual  number  of  bricks  purchased  and  used,  and  wall  measure,  the 
number  of  bricks  there  would  be  on  the  basis  of  22^  bricks  to  every 
superficial  foot  of  a  12-inch  wall. 

No  deduction  is  made  for  openings  of  less  than  80  superficial  feet, 
and  when  deductions  are  made  for  larger  openings  the  width  is 
measured  two  feet  less  than  the  actual  width.  Hollow  walls  are 
measured  as  if  solid. 

Footings  are  generally  measured  in  with  a  wall  by  adding  the 


*      SUPERINTENDENCE   OF  BRICKWORK.  403 


width  of  the  projections  to  the  height  of  the  wall.  Thus — if  the 
footings  project  6  inches  on  each  side  of  a  wall,  i  foot  is  added  to 
the  actual  height  of  the  w^all. 

A  chimney-breast  or  pilaster  is  measured  by  multiplying  the  girth 
of  the  breast  or  pilaster  from  the  intersections  with  the  wall,  by  the 
height,  and  the  product  thus  obtained  by  the  number  of  bricks  corre- 
sponding to  the  thickness  of  the  projection.  Flues  in  chimneys  are 
always  measured  solid. 

A  detached  chimney  or  chimney-top  is  measured  the  same  as  a 
wall  having  a  length  equal  to  the  sum  of  one  long  side  and  the  two 
ends  of  the  chimney,  and  having  a  thickness  equal  to  that  of  the 
chimney. 

The  rule  for  independent  piers  is  to  multiply  the  height  of  each 
pier  by  the  distance  around  it  in  feet  aud  to  consider  the  product  as 
the  superficial  area  of  a  wall  whose  thickness  is  equal  to  the  width 
of  the  pier.  In  practice  many  masons  measure  only  one  side  and  one 
end  of  a  pier  or  chimney. 

Arches  of  common  bricks  over  openings  of  less  than  80  super- 
ficial feet  are  usually  disregarded  in  estimating.  If  an  arch  is  over 
a  larger  opening  the  height  of  the  wall  is  measured  from  the  spring 
of  the  arch.  No  deduction  is  made  in  wall  measurement  for  stone 
sills,  caps  or  belt-courses,  nor  for  stone  ashlar,  if  the  same  is  set  by 
the  brick-mason.  If  the  ashlar  is  set  by  the  stone-mason  the  thick- 
ness of  the  ashlar  is  deducted  from  the  thickness  of  the  wall. 

Custom  varies  somewhat  in  the  measurement  of  brickwork,  and 
when  work  is  done  "by  the  thousand  in  the  wall,"  the  contract  should 
state  distinctly  how  the  work  is  to  be  measured,  and  if  deductions 
are  to  be  made  for  the  openings  and  stonework.  Some  builders 
reduce  all  the  brickwork  to  cubic  feet  and  estimate  the  cost  in  that 
way  for  common  brickwork. 

5.    SUPERINTENDENCE  OF  BRICKWORK. 

383.  DETAILS  REQUIRING  SPECIAL  ATTENTION.— 
The  various  portions  of  the  work  that  require  special  superintend- 
ence have  been  mentioned  in  describing  the  manner  of  doing  the 
work.  In  general  the  particular  details  in  which  brickwork  is  com- 
monly slighted  are  the  wetting  and  the  laying  of  the  bricks.  The 
importance  of  wetting  the  bricks  is  fully  set  forth  in  Article  343. 
In  laying  the  bricks  it  is  often  difficult  to  get  the  masons  to  use 
sufificient  mortar  to  thoroughly  fill  all  the  joints  and  to  get  them  to 


404 


BUILDING  CONSTRUCTION.        (Ch.  VII)* 


''shove"  the  bricks.  The  quaHty  of  the  mortar  should  also  be  fre- 
quently examined,  as  brick-masons  in  some  localities  like  to  mix  a 
little  loam  with  the  sand  to  make  the  mortar  ''work  well." 

The  bonding  of  the  walls  should  be  watched  to  see  that  the  bond 
courses  are  used  as  often  as  specified.  The  bonding  of  piers  should 
be  particularly  looked  after.  The  laying  of  the  face-bricks  and 
ornamental  details  requires  more  skill,  but  is  not  so  apt  to  be  slighted 
as  are  the  backs  of  the  walls. 

The  superintendent  should  also  see  that  the  dimensions  of  the 
building  are  properly  followed,  that  openings  are  left  in  their 
proper  places,  and  that  the  courses  are  kept  level  and  the  walls  built 
plumb. 

In  very  high  stories,  and  particularly  in  those  of  halls  and 
churches,  the  walls  should  be  stayed  with  temporary  braces  until 
the  permanent  timbers  can  be  built  in.  It  is  also  important  to  see 
that  all  bearing-plates  are  well  bedded,  all  floor-anchors  securely 
built  in,  all  recesses  for  pipes,  etc.,  which  are  marked  on  the  plans, 
left  in  the  proper  places  and  all  smoke-flues  and  vent-flues  smoothly 
plastered. 


Chapter  VIII. 


Architectural  Terra-cotta. 


384.  COMPOSITION  AND  MANUFACTURE.— Terra-cotta 
is  composed  of  practically  the  same  material  asjDricks,  and  its  char- 
acteristics, as  far  as  the  material  is  concerned,  are  the  same.  Terra- 
cotta, however,  requires  for  its  successful  production  a  much  better 
quality  of  clay  than  is  generally  used  for  bricks,  while  the  process  of 
manufacture  is  entirely  different. 

The  first  consideration  in  the  manufacture  of  terra-cotta  is  the 
selection  of  the  material.  No  one  locality  gives  all  the  clay  required 
for  first-class  material,  and  each  shade  and  tint  of  terra-cotta  requires 
the  mingling  of  certain  clays  from  different  localities  to  regulate  the 
color. 

A  great  variety  of  excellent  clays  are  mined  in  Northern  and  Cen- 
tral New  Jersey,  large  quantities  being  marketed  annually  for  mak- 
ing terra-cotta,  as  well  as  for  fire-bricks,  pottery,  tiles,  etc.  The 
color  varies  from  light  cream  to  dark  red. 

A  partial  vitrification  of  the  body  is  desirable,  but  a  clay  that  is 
too  fusible  causes  warping  in  the  kiln.  To  overcome  this  tendency 
to  twist,  one  at  least  of  the  component  clays  should  be  highly  refrac- 
tory, and  to  further  insure  straightness,  from  20  to  25  per  cent  of 
ground  burned  clay  called  ''grog"  or  ''chamotte"  should  be  added. 

The  clay  after  being  mined  is  sometimes  seasoned  before  being 
delivered  to  the  factory.  After  being  received,  any  one  of  several 
methods  is  employed  to  thoroughly  grind  and  mix  the  clay  with 
grog  and  water,  and  usually  it  is  finally  tempered  in  a  pug-mill 
before  being  sent  to  the  pressing  room. 

If  several  pieces  of  terra-cotta  of  the  same  size  and  shape  are 
required,  a  full-sized  model  of  plaster  and  clay  is  first  made,  and  from 
this  a  plaster  mold  is  taken.  In  the  making  of  these  models  and 
molds  the  highest  grade  of  skilled  labor  is  required.  When  the 
molds  are  dry  they  are  sent  to  the  pressing  department ;  here  the 
plastic  clay  is  pressed  into  the  molds  by  hand,  and  when  partially 
dry  the  work  is  turned  out  on  the  floor.   The  ware  is  then  ready  for 

405 


4o6 


BUILDING  CONSTRUCTION.  (Ch.VIII) 


the  carver  or  modeller,  if  it  is  decorative  work  that  requires  the  use 
of  their  tools  ;  or  for  the  clay  finisher  if  it  only  requires  undercutting 
or  some  special  work  to  make  it  fit  in  with  other  construction. 

The  work  is  carefully  dried  on  the  drying  floor  or  in  the  dryers 
and  is  then  ready  to  receive  the  surface  treatment.  This  is  done 
by  spraying  on  the  surface  of  the  terra-cotta,  by  means  of  com- 
pressed air  and  an  atomizer,  a  thin  "slip"  or  liquid  mixture  which, 
when  burned,  give^  the  terra-cotta  a  surface  which  is  vitrified, 
full-glazed,  etc.,  as  the  case  may  be.  This  operation  also  gives  the 
terra-cotta  greater  evenness  in  tone  and  its  exact  shade  of  color,  the 
body  colors  used  being  comparatively  few,  while  the  surface  colors 
are  almost  without  limit. 

It  is  then  put  into  the  kilns,  where  it  remains  from  seven  to 
fifteen  days,  according  to  the  size  of  the  kiln,  before  it  is  ready  for 
use.  The  kilns  used  are  the  down-draught,  beehive-shaped  kilns, 
and  an  inside  lining  or  "muffle"  is  used  to  prevent  the  flames  from 
coming  in  direct  contact  with  the  terra-cotta.  In  this  drying  and 
burning  process  all  the  water  in  the  clay  is  expelled,  and  in  conse- 
quence, a  shrinkage  in  the  size  of  the  pieces  takes  place.  This 
shrinkage  is  about  one  inch  to  the  foot,  for  which  allowance  is  made 
by  the  draughtsman,  who  makes  the  drawings  for  the  mold-maker. 
The  pieces  are  then  carefully  inspected,  fitted  and  numbered,  in 
accordance  with  setting  drawings  prepared  for  that  purpose. 

The  fitting  operation  consists  in  placing  the  various  pieces  in  the 
relative  positions  which  they  would  have  in  the  building,  and  then 
by  the  use  of  the  chisel,  in  trimming  joints  where  necessary,  so  that 
the  pieces  will  all  fit  accurately  together.  By  the  use  of  the  rubbing- 
bed,  the  joints  are  rubbed  to  an  absolutely  straight  line  in  the  same 
manner  that  stonework  is  rubbed.  The  rubbing  of  the  joints  is  of 
great  advantage  in  ashlar-work,  as  it  insures  absolute  alignment  of 
the  joints. 

The  numbering  operation  consists  in  marking  each  piece  with  a 
number  for  identification.  A  corresponding  number  is  placed  on 
the  setting  drawings.  The  work  is  then  finally  shipped  to  the 
building. 

If  only  one  or  two  pieces  of  terra-cotta  are  to  be  made,  or  if 
no  repetition  is  intended,  no  molds  are  used,  the  clay  being  modelled 
by  hand,  with  the  use  of  templates,  into  the  required  shape.  Single 
pieces  of  modelling  are  worked  up  on  ashlar  and  plain  blocks.  The 
finished  product  thus  bears  directly  the  impress  of  the  modelling 


ARCHITECTURAL  TERRA-COTTA. 


407 


^artist.  It  can  be  studied,  improved  or  modified,  and,  when  entirely 
satisfactory,  burned.  On  this  account  terra-cotta  possesses,  for 
highly  decorative  work,  an  advantage  over  all  other  building 
materials. 

Terra-cotta  has  this  advantage  even  where  repetition  is  intended 
and  molds  are  made,  because  the  ornamental  portions  of  the 
models  are  made  of  clay,  which  under  all  circumstances  is  the  best 
material  that  can  be  used  for  modelling  purposes ;  they  can 
therefore  be  studied  and  improved  before  the  molds  are  made. 
The  architect  sometimes  examines  the  models  in  person,  and  the 
alterations  are  then  made  directly  under  his  eye.  Sometimes 
photographs  are  made  and  sent  for  his  inspection  and  approval. 
If  the  ornament  is  of  sufficient  importance  to  make  it  desirable  to 
bear  the  direct  touch  of  the  modelling  artist,  he  can  retouch  each 
piece  after  it  is  turned  out  of  the  mold.  • 

Terra-cotta  is  usually  made  in  blocks  from  24  to  30  inches  long, 
from  6  to'  12  inches  deep  and  of  a  height  determined  by  the  char- 
acter of  the  w^ork.  To  save  material  and  prevent  warping,  the  blocks 
are  formed  of  an  outer  shell,  connected  and  braced  by  partitions 
about  inches  thick.  The  partitions  should  be  arranged  so  that 
the  spaces  do  not  exceed  6  inches,  and  should  have  numerous  holes 
in  them  to  form  clinches  for  the  mortar  and  brickwork  used  for 
filling. 

385.  THE  SURFACE  OF  TERRA-COTTA.— The  body  of  all 
good  terra-cotta  is  very  much  the  same,  but  there  are  several  ways 
of  treating  the  surface,  resulting  in  products  which  may  be  classified 
as  follows :  Standard  Terra-cotta,  Vitreous  Surface  Terra-cotta, 
Mat-glazed  Terra-cotta,  Full-glazed  Terra-cotta  and  Polychrome 
Terra-cotta. 

Standard  Terra-cotta  has  no  surface  given  it,  which  affects  its 
porosity,  a  drop  of  water  placed  upon  it  being  soon  absorbed.  It 
will  absorb,  also,  a  great  amount  of  dirt  from  the  atmosphere  and 
will  become  very  much  darker  from  continued  exposure.  On  some 
buildings  this  "weathering  down"  is  not  objectionable;  in  fact  it 
sometimes  lends  a  charm,  producing  an  antique  appearance  which  is 
often  very  desirable  from  an  artistic  point  of  view.  Someone  has 
said  that  "time  is  the  greatest  artist,"  and  therefore,  when  it  is 
desired  to  produce  an  aged  effect,  Standard  Terra-cotta  should  be 
used.  It  is,  consequently,  a  good  material  to  use  for  "rustic  work," 
in  connection  with  country  houses,  college  buildings,  gateways,  cer- 


4o8 


BUILDING  CONSTRUCTION. 


(Ch.  VIII) 


tain  styles  of  churches,  etc.  This  class  of  material  is  made  in  any 
color  desired. 

Vitreous  Surface  Terra-cotta  has  a  very  thin  spray  on  the  surface 
which  vitrifies  in  the  burning  process,  forming  a  thin  glaze  which 
sheds  water.  This  terra-cotta  will  not  absorb  much  dirt  from  the 
atmosphere,  as  the  rain  of  each  storm  washes  it  off ;  it  therefore 
practically  retains  its  original  color.  This  class  of  material  is  made 
in  any  color  desired  and  is  used  more  than  any  other  kind  at  the 
present  time,  as  it  seems  to  satisfy  the  greatest  number  of  require- 
ments. The  'Tlatiron"  Building,  New  York,  D.  H.  Burnham  & 
Company,  architects,  was  of  this  material. 

Mat-glazed  Terra-cotta. — In  Western  cities  where  soft  coal  is 
used,  and  where,  consequently,  most  buildings  are  cleanecf  about 
once  every  year,  any  material  of  a  non-porous  nature  is  very  desir- 
abre ;  and  it  has  been  found  that  glazed  terra-cotta  ranks  with  the 
most  superior  materials  in  this  respect.  On  this  account  white 
glazed  terra-cotta  is  used  to  a  great  extent  in  these  cities.  The 
luster  of  the  glaze  is  deadened  for  artistic  reasons,  the  glare  of  the 
sunlight  on  full-glazed  terra-cotta  being  very  severe.  This  is  now 
done  in  the  process  of  burning,  as  it  has  been  found  that  sand- 
blasting the  material  neutralizes  the  purpose  of  the  glaze ;  and  this 
method  has  long  been  abandoned  by  the  leading  manufacturers. 
There  are  m_any  examples  of  buildings  constructed  of  this  material 
in  the  West,  and  the  most  notable  example  in  the  East  is  the 
Plaza  Hotel,  Fifty-ninth  Street,  New  York,  H.  J.  Hardenburg, 
architect. 

Full-glazed  Terra-cotta. — For  light-courts,  loggias  to  office- 
buildings,  theatres,  interiors  of  railroad  stations,  ferry-houses, 
train-sheds,  natatoriums,*  power-houses,  etc.,  the  full-glazed  terra- 
cotta is  preferable,  as  it  helps  illumination  and  gives  a  more  brilliant 
effect. 

Polychrome  Terra-cotta. — The  full-glazed  terra-cotta  and  mat- 
glazed  terra-cotta  are  made  in  any  color  required,  and  when  various 
colors  are  used  on  the  same  building  the  material  is  termed  ''poly- 
chrome." The  various  colors  may  be  applied  to  the  same  piece  if 
desired,  or  each  separate  color  may  be  kept  on  a  separate  piece,  if 
the  design  will  permit.  The  next  article,  386,  ''Color  of  Terra- 
cotta," explains  the  uses  to  which  this  class  of  material  may  be 
put. 

386.    COLOR  OF  TERRA-COTTA.— Within  the  past  twenty 


ARCHITECTURAL  TERRA-COTTA. 


409 


years  a  great  impetus  has  been  given  to  the  production  of  special 
colors  in  architectural  clay  products.  In  1885  fully  four-fifths  of 
the  terra-cotta  produced  in  the  United  States  was  red;  now  (in 
I9q3)  there  is  less  of  red  used  than  of  almost  any  other  color. 
Buffs  and  grays  of  several  shades,  white  and  cream-white  and  the 
richer  and  warmer  colors  of  old-gold  and  brown  are  now  the 
prevailing  colors. 

By  the  use  of  ceramic  colors  almost  any  required  tone  may  be 
produced  and  the  effect  obtained  by  using  glazed  terra-cotta  of 
various  colors  in  combination,  such  as  blue,  yellow,  white,  purple, 
brown,  old-gold,  green,  red,  etc.,  is  often  very  beautiful.  If  any 
particular  shade  of  color  not  included  in  the  manufacturer's 
standard  samples  is  desired,  the  architect  should  consult  with  the 
manufacturer,  who  will  then  experiment  until  the  required  color  is 
not  only  produced,  but  guaranteed  to  be  permanent  and  free  from 
all  tendency  to  crack  cr  craze. 

It  is  quite  generally  agreed  that  there  is  a  great  field  for  this 
polychrome  terra-cotta,  especially  for  theatres,  restaurants  and 
buildings  of  a  similar  nature ;  for  interiors,  loggias,  fountains,  etc. ; 
for  department-stores,  when  a  striking  design  is  required  for 
advertising  purposes ;  and  for  certain  styles  of  church  work. 
Although  the  art  of  using  colored  terra-cotta  is  very  ancient,  having 
been  in  practice  before  the  Christian  Era,  it  is,  to  some  extent,  an 
undeveloped  field  in  this  country  and  offers  alluring  possibilities  in 
architectural  design  and  construction.  It  can  be  used  in  a  very 
modest  and  sparing  manner,  as  well  as  very  profusely;  and  either 
in  soft  tints  or  in  brilliant  colors,  as  the  taste  of  the  architect  may 
dictate.  Where  a  rich  decorative  treatment  is  required,  as  in  the 
interiors  of  large  public  buildings  like  our  great  union-stations, 
hotels,  theatres,  etc.,  polychrome  terra-cotta  can  be  employed  most 
effectively  and  economically. 

In  variety  and  beauty  of  tones,  polychrome  terra-cotta  has  now 
reached  a  very  high  standard  of  excellence,  and  may  be  used  by  the 
architect  to  express  the  highest  type  of  his  art.  The  almost  un- 
limited possibilities  presented  by  the  judicious  application  of  colored 
glazes  for  exteriors,  as  well  as  for  interiors,  has  awakened  an 
unusual  interest  in  the  use  of  polychrome  terra-cotta,  a  building 
material  with  superior  qualities  of  resistance  against  the  deterio- 
rating effects  of  time  and  of  the  action  of  fire  and  frost. 

Under  the  direction  of  some  of  our  most  noted  architects  a  large 


410 


BUILDING  CONSTRUCTION.  (Cii.VIII) 


amount  of  this  polychrome  terra-cotta  has  been  produced  during 
the  last  few  years,  and  the  following  are  some  notable  examples 

Academy  of  Music,  Brooklyn,  Herts  &  Tallant,  architects ; 
Madison  Square  Presbyterian  Church,  Madison  Square,  New  York. 
McKim,  Mead  &  White,  architects;  Statler  Hotel,  Buffalo,  N.  V.  ; 
Essenwein  &  Johnson,,  architects ;  Munsey  Building,  Washington, 
D.  C,  McKim,  Mead  &  White,  architects;  St.  Ambrose  Church, 
Brooklyn,  N.  Y.,  Geo.  H.  Streeter,  architect ;  Seminary  for  the 
Society  of  Redemptorist  Fathers,  Esopus,  N.  Y.,  F.  Joseph 
Untersce,  architect;  the  New  York  Subway  Stations,  Heins  & 
La  Farge,  architects;  the  Hudson  Terminal  Concourse,  New 
York,  Clinton  &  Russell,  architects ;  a  number  of  railroad  stations, 
New  York,  New  Haven  &  Hartford  Railroad,  Cass  Gilbert,  archi- 
tect ;  and  the  Automobile  Club  of  America,  New  York,  Ernest 
Flagg,  architect.  In  the  West,  abo,  colored  terra-cotta  is  being 
used  to  a  great  extent.  Polychromatic  .ornamient  like  that  of  the 
Madison  Square  Presbyterian  Church,  New  York,  and  the  Brook- 
lyn Academy  of  Music,  would  seem  to  demonstrate  that  our  climate 
and  atmosphere  are  well  adapted  to  the  use  of  polychrome  exterior 
construction,  especially  when  produced  in  glazed  tile  or  terra-cotta. 

387.  USE  OF  TERRA-COTTA.— Terra-cotta  is  not  imitation 
stone  and  should  not  be  used  as  such. 

It  is  a  material  having  peculiar  qualities  which  give  a  distinctive 
character,  and  therefore,  to  be  successfully  used,  it  should  be  em- 
ployed in  such  a  way  that  its  individual  characteristics  will  be 
expressed,  and  not  in  such  a  way  that  it  will  appear  as  an  imitation 
of,  or  as  a  cheap  substitute  for,  some  more  expensive  material.  This 
may  be  brought  about  in  several  w^ays.  There  may  be  used  certain 
architectural  forms  and  certain  styles  of  ornament  more  character- 
istic of  terra-cotta  than  of  any  other  material.  One  architecty  has 
evolved  a  certain  style  that  he  has  applied  to  many  buildings,  and 
which  is  not  suitable  to  any  material  other  than  terra-cotta.  This 
may  be  said  of  both  the  form  and  ornamentation  of  his  buildings. 
The  architects  $  of  the  'Tlatiron"  Building  and  of  the  Wanamaker 
Building  in  New  York  have  successfully  used  this  material  for  its 
own  sake  and  not  as  an  imitation.    Another  firm  of  architects§  have 

*  The  polychrome  terra-cotta  for  the  buildings  mentioned  was  made  by  the  Atlantic 
Terra-cotta  Company,  J\ew  York.  This  company  rendered  most  valuable  assistance  in  the 
rewriting  of  this  chapter. 

t  Mr.   L.   H.   Sullivan,  Chicago. 

t  I).  H.  Burnham  &  Co.,  Chicago. 

§  McKim,  Mead  &  White,  New  York. 


ARCHITECTURAL  TERRA-COTTA. 


411 


used  profusely  modelled  terra-cotta  to  produce  highly  ornamental 
effects  not' so  easily  obtainable  in  other  materials,  and  their  recent 
use  of  colored  terra-cotta  is  typical  of  this  material  alone. 

In  the  West  Street  Building,  New  York,  the  architect*  has  made 
a  design  distinctly  expressive  of  the  material  used,  viz. :  terra-cotta. 
This  is  noticeable  in  the  ornamentation,  in  the  form  of  cornices  and 
molding,  in  the  coloring  and  even  in  the  plain  shaft  of  the 
building. 

In  the  Brooklyn  Academy  of  Music  the  architectsf  have 
accomplished  this  result  by  the  use  of  color. 

In  regard  to  the  use  of  colored  terra-cotta,  it  has  been  said  that 
''it  is  by  the  use  of  polychrome  terra-cotta  that  the  material  has  its 
best  opportunity  for  expressing  its  individual  character.  It  was  so 
in  antiquity,  in  the  Middle  Ages,  and  is  so  at  the  present  time, 
because  polychrome  terra-cotta  is  a  material  complete  in  itself,  and 
used  for  its  own  sake ;  and  it  cannot  by  any  means  be  considered 
in  imitation  of,  nor  a  substitute  for,  something  better." 

388.  DURABILITY. — The  principal  value  of  terra-cotta  lies  in 
its  durability.  When  made  of  the  right  materials  and  properly 
burned  it  is  impervious  to  water,  or  nearly  so;  and  when  glazed  it 
is  absolutely  impervious,  and  hence  not  subject  to  the  disintegrating 
action  of  frost,  which  is  a  powerful  agent  in  the  destruction  of 
stone.  It  does  not  "vegetate,"  as  is  the  case  with  many  stones.  The 
ordinary  acid  gases  contained  in  the  atmosphere  of  cities  have-  no 
effect  upon  it,  and  the  dust  which  gathers  on  the  moldings  is 
washed  away  by  every  rainfall.  Underburned  terra-cotta  does  not 
possess  these  qualities  to  so  high  a  degree,  as  it  is  more  or  less 
absorbent.  Another  great  advantage  possessed  by  terra-cotta  is  its 
resistance  to  heat,  which  makes  it  a  most  desirable  material  for  the 
trimmings  and  ornamental  work  in  the  walls  of  fire-proof  buildings. 
Although  terra-cotta  has  been  used  in  this  country  for  but  a  com- 
paratively short  time,  it  has  thus  far  proved  very  satisfactory,  and 
the  characteristics  above  indicated  would  point  to  its  ranking,  in 
common  with  the  better  qualities  of  bricks,  with  the  most  desirable 
of  building  materials  if,  indeed,  it  is  not  the  most  durable  of  all 
building  materials. 

In  Europe  there  are  numerous  examples  of  architectural  terra- 
cotta which  have  been  exposed  to  the  weather  for  three  or  four 

*  Mr.  Cass  Gilbert,  New  York, 
t  Herts  &  Tallant,  New  York. 


412 


BUILDING  CONSTRUCTION.  (Ch.VIII) 


centuries  and  which  are  still  in  good  condition,  while  examples  of 
stonework,  subjected  to  the  same  conditions,  are  more  or  less  worn 
and  decayed. 

"There  is  at  the  Louvre  in  Paris,  to-day,  some  glazed  terra-cotta 
said  to  have  been  made  by  the  Assyrians  in  the  sixth  century 
before  Christ,  and  in  other  museums  there  are  some  vases  and  other 
ancient  terra-cottas  from  Egypt  and  Greece,  as  well  as  the  famous 
Lucca  Delia  Robbia  work  made  in  the  Middle  Ages,  many  of  these 
pieces  being  as  perfect  as  if  recently  made.  All  these  ancient  terra- 
cottas tell  the  story  of  durability  and  proclaim  terra-cotta  to  be  a 
material  worthy  of  the  genius  of  those  artists  of  antiquity  who 
wrought  so  beautifully  in  this  sympathetic  medium. 

"Specimens  made  two  thousand  years  ago  have  been  found  in  the 
ruins  of  ancient  buildings  in  an  almost  perfect  state  of  preservation, 
v^hile  the  stones  among  which  they  have  been  found  have  long 
since  crumbled  away  from  their  original  size  and  shape." 

389.  INSPECTION.— A  sharp  metallic,  bell-like  ring  and  a 
clean,  close  fracture  are  good  proofs  of  homogeneity,  compactness 
and  strength.  Perfection  of  form  is  in  the  highest  degree  essential, 
and  can  result  only  from  a  homogeneous  material  and  a  thorough 
and  experienced  knowledge  of  firing. 

No  spalled,  chipped  or  warped  pieces  of  terra-cotta  should  be 
accepted,  and  the  pieces  should  be  so  hard  that  they  will  resist 
scratching  with  the  point  of  a  knife.  The  blocks  should  be  of  uni- 
form color  also,  and  all  moldings  should  come  together  perfectly 
at  the  points. 

Terra-cotta  with  a  vitreous  surface  and  mat-glazed  terra-cotta 
should  be  so  non-absorbent  that  water  will  lie  in  drops  on  its  sur- 
face without  being  quickly  absorbed.  Full-glazed  terra-cotta  should 
be  so  non-absorbent  that  ink  will  not  penetrate  the  surface  and 
may  be  entirely  washed  away  with  water. 

390.  LAYING  OUT  TERRA-COTTA.— On  account  of  the 
manner  in  which  terra-cotta  shrinks  in  the  drying  and  burning 
process,  it  always  has  a  tendency  to  warp  and  to  vary  in  size. 

By  careful  methods  in  manufacture  these  tendencies  are  kept 
under  control  to  a  great  extent,  but  it  is  always  best  in  jointing 
terra-cotta  to  arrange  the  joints  so  as  to  provide  for  the  adjust- 
ment of  any  such  inaccuracies.    Figure  245*,  showing  a  terra-cotta 


*  Courtesy  of  the  Atlantic  Terra-cotta  Company,  New  York. 


ARCHITECTURAL  TER^RA-COTTA. 


413 


doorway  with  hidden  joints,  illustrates  a  system  of  back  joints  to 
provide  for  such  adjustment.  If  any  piece  of  the  jambs  or  ashlar 
shrinks  too  much,  or  too  little,  there  is  an  edge  on  that  piece  that 


-  EL£  VAT  1^/1  ~  -y^CrUOM' 


'  PLAN       A  A  -  'D£TAJL^J/7I/^T 


fo  concccd        rr^^iy    of  fbe  Joujti        •  jiOiJifcl*  - 
Thit  rodlyod  of  joiijifvnj  •  cooeefcU  njifcnjf    joiofi  u<V)icb 
would  c^ljerujise    ahoi*  {o  <b«  delj-ufjeot  to  tb'- 
appea-rajjcc   of   fbe  •  deivg"}.— 

 ...  I 

Fig.  245. — Terra-cotta  Doorway  with  Hidden  Joints. 

may  be  cut  away  to  the  proper  size  if  necessary,  without  affecting 
the  *'take-up"  of  any  members. 


414 


BUILDING  CONSTRUCTION.  '  (Ch.VIII) 


Fig.  246. — Construction  of  Terra-cotta  Columns. 


The  inner  jamb  and  arch-pieces  are  made  separate  for  the  same 
reason ;  and  the  joint  in  the  cap  is  hidden  in  the  Hnes  of  the  orna- 
ment, so  that  if  trimming  becomes  necessary,  it  will  not  spoil  the 
appearance  of  the  delicate  modelling.    It  is  unnecessary  to  joint 


ARCHITECTURAL  TERRA-COTTA. 


415 


terra-cotta  with  alternate  deep  and  shallow  bonds  or  with  bond- 
blocks  for  jambs,  etc.,  because  the  brick  backing-  may  be  and  should 
be  built  into  the  hollow  spaces  in  the  back  of  the  terra-cotta.  By 
following  this  method  and  by  using  anchors,  plumb  joints  through 
many  courses  at  the  edge  of  the  piers,  jambs,  pilasters,  etc.,  are 
absolutely  secure. 

Fig.  245'''"  is  laid  out  in  this  manner,- with  the  result  that  the  joints 
which  usually  detract  from  the  appearance  of  the  terra-cotta  are 
so  hidden  in  the  lines  of  the  design  that  the  number  apparent  is 
reduced  to  a  minimum.  Although  the  pieces  here  shown  are  smalf 
in  size  when  compared  with  stonework,  this  method  of  jointing 
gives  the  same  effect  that  would  be  produced  if  very  large  pieces 
were  used.  Even  though  the  scale  of  this  design  were  larger,  this 
same  method  could  be  used,  as  pieces  up  to  3  feet  and  3  feet  6 
inches  long  are  practicable  when  the  width  is  not  over  i  foot  6 
inches,  long  narrow  pieces  giving  the  best  result. 

Columns  should  be  made  with  bands,  if  possible,  or  else  jointed 
as  shown  in  Fig.  246,*  showing  the  construction  of  terra-cotta 
columns,  as  the  inaccuracy  in  shrinkage  is  much  more  apparent 
when  so  many  small  members  like  the  fillets  between  the  flutes 
must  take  it  up. 

Column  A  shows  shaft  built  up  of  drums.  Diameter  not  to 
exceed  i  foot  8  inches. 

Column  B  shows  design  dispensing  with  vertical  joints  and  con- 
cealing bed-joints.    Diameter  not  to  exceed  3  feet. 

Column  C  shows  a  method  of  designing  column  shafts  over  r 
foot  8  inches  in  diameter,  with  reeds  instead  of  flutes,  thus  main- 
taining the  massive  appearance  of  a  plain  column  and  concealing 
the  vertical  joints  in  the  lines  of  the  reeding. 

Column  D  shows  a  practical  method  of  jointing  fluted  column 
shafts  over  i  foot  8  inches  in  diameter.  t 

Column  E,  with  sections  i  and  2,  shows  two  methods  of  modified 
fluting  for  classical  columns,  with  the  vertical  joints  of  the  shafts 
concealed. 

As  the  blocks  of  terra-cotta  are  made  from  molds  of  fixed  sizes, 
repetition  is  economy ;  therefore,  a  great  saving  in  expense  is 
obtained  by  making  the  various  portions  of  the  building  typical. 
The  windows,  as  far  as  possible,  should  all  be  the  same  height. 


*  Courtesy  of  the  Atlantic  Terra-cotta  Company,  New  York. 


4i6  BUILDING  CONSTRUCTION.  '\  (Ch.VIII) 

opening  and  reveal ;  the  piers  should  be  the  same  width ;  the 
pavilions  or  bays  should  be  the  same  size  and  design ;  tfie  different 
stories  should  be  the  same  height  and  design  as  far  as  possible,  and 
all  ornaments  should  be  spaced  to  conform  to  the  centering  of  the 
jointing  scheme. 

Ashlar-work  should  have  some  treatment  of  jointing  that  will 
allow  for  trimming  and  adjustment,  and  where  possible,  members 
should  be  introduced  to  break  up  the  severe  lines.    Figure  247* 


\  \\- 

k 

1    •  i  ] 

y    r  1 

1      1  1 

,   1  ! 

1      1  1 

1  1 

1    _  J 

i  1 

r      1  1 

1 

.  4-,  1  ^  i-f-  .  ,  ^1.'-. 

\  1 

1  i 

-DtJiaH  -B'-                                            -  DEJlciN  ■  C-  -Ocji&h-'D- 

Fig.  247. — Terra-cotta  Piers.     Different  Treatments. 


shows  several  suggestions  for  the  treatment  of  a  pier,  which  might 
occur  in  the  lower  stories  of  a  building. 

In  this  figure,  design  A  shows  a  first-story  pier  designed  for  stone 
construction.  As  these  severe  lines  demand  exact  alignment,  this 
construction  is  unsatisfactory  for  terra-cotta,  because  there  are  no 
vertical  joints  which  may  be  trimmed  to  afford  adjustment  where 
uneven  shrinkage  occurs. 

Design  B  shows  the  same  pier  altered  to  permit  a  practical  method 
of  jointing.  These  rustications  break  the  severe  lines,  so  that  any 
inexactness  which  may  occur  will  not  be  apparent.  The  massive 
appearance  of  the  pier  is  increased  by  this,  alteration.    This  could 


*  Courtesy  of  the  Atlantic  Terra-cotta  Company,  New  York. 


ARCHITECTURAL  TERRA-COTTA. 


417 


not  be  applied  to  a  corner  pier,  as  the  return  would  be  too  great. 
These  pieces  could  be  made  not  more  than  i  foot  6  inches  return. 

Design  C  shows  the  same  pier  altered  to  permit  of  smaller  pieces. 
The  vertical  joints  may  be  trimmed  to  afford  adjustment  where  the 
shrinkage  has  been  uneven ;  and  therefore  corner  piers  may  be 
joiMted  in  this  manner.  This  design  is  very  satisfactory  when  in 
harmony  with  the  general  design  of  the  building. 

Design  D  shows  the  same  pier  jointed  in  such  a  manner  as  to 
leave  unaltered  the  profile  of  the  pier.  This  preserves  the  severe 
lines  and  massive  appearance,  while  the  joints  are  so  arranged  as 
to  allow  trimming  to  afford  proper  adjustment  and  adherence  to 
exact  measurements. 

Sills  7  inches  deep  may  be  made  as  much  as  four  feet  in  length. 
Blocks  in  belt-courses,  cornices,  etc.,  usually  should  not  exceed  2 
feet  6  inches,  or  3  feet  in  length. 

Balusters  should  be  cut  into  two  or  three  pieces  in  height,  de- 
pending upon  the  size,  and  panels  and  tracery  should  be  cut  into 
pieces  so  as  to  provide  for  adjustment  in  setting. 

Raised  joints  should  be  used,  as  covered  joints  are  delicate,  and 
are  therefore  usually  broken,  to  a  greater  or  less  extent,  in  handling 
and  setting  at  the  building. 

It  is  better  for  architects  to  place  the  jointing  and  construction 
of  terra-cotta  work  in  the  hands  of  the  manufacturer,  who  may  be 
considered  an  expert  in  his  line.  He  knows  better  than  the  archi- 
tect does  the  proper  methods  to  employ.  If,  however,  the  archi- 
tect wishes  to  superintend  this  part  of  the  work,  the  usual  course 
pursued  is  to  have  the  manufacturer  make  factory  working-draw- 
ings and  submit  them  to  the  architect  for  his  inspection  and 
approval. 

391.  COMPARISON  OF  BAD  AND  GOOD  METHODS  OF 
TERRA-COTTA  CONSTRUCTION.— Figs.  248  to  256*  show 
various  typical  illustrations  of  terra-cotta  details,  with  faulty  or 
incorrect  methods  of  construction  sometimes  seen  and  with  the 
correct  and  approved  methods  also  indicated  for  purpose  of 
comparison. 

Unless  otherwise  noted  on  the  drawings,  the  scale  shown  in  Fig. 
248  is  the  one  used  for  all  of  the  nine  figures,  248  to  256,  both 
inclusive. 


*  These  figures,  248  to  256,  are  reproduced  through  the  courtesy  of  the  Northwestern 
Terra-cotta  Company,  of  Chicago. 


4i8  BUILDING.  CONSTRUCTION.  (Ch.VIII) 


Fig.  248. — ^Terra-cotta  Rail  and  Baluster.    Bad  and  Good  Construction. 


Fig.  250. — a.  Cornice  Coping,  Poor  Construction,    b.  Standard  Terra-cotta  Joints. 


ARCHITECTURAL  TERRA-COTTA 


419 


Fig.  253. — Terra-cotta  Engaged  Columns.    Bad  and  Good  Construction, 


420 


BUILDING  CONSTRUCTION.  (Ch.VIII) 


^fJew<»lk  will  liAve  a  {toorteo.  oioxiIat 
■fe»  "ttaAi"  jk^>wn  K;"fee  cJtjteJ  liaes. 

>0  A   lev<?r  tre^t  <^[f  "fee 


lb  *u^»iol  trcAin^  "fee  plirxfe  "fee 


Fig.  254. — Terra-cotta  Column-base  and  Sidewalk.    Bad  and  Good  Construction. 


\J 

a: 

\: 

Are  t>*^  And  .jlzoold 
l?e  Av/oided.  .Tke 

l! 

In.  CAse  c^HikeklUwArcJie^ 
vlffe-wide  apA.oi'tfee  1 

preverxteol  'y^rn.  ^Iippia^ 

us,\n.ar  meisJ  dowel} 
A-S  »|iown,  <sl~  "Al*ad  |j. 

Fig.  256. — Terra-cotta  Flat  Arches.    Bad  and  Good  Construction. 


ARCHITECTURAL  TERRA-COTTA. 


421 


The  titles  of  the  figures  and  the  notes  on  each,  with  the  detailed 
construction  shown  in  the  drawings  themselves,  explain  clearly  the 
good  and  bad  methods  of  putting  together  terra-cotta  in  some  of 
the  important  parts  of  buildings. 

392.  SETTING  AND  POINTING.  —  ^^r///;/"-.  —  Terra-cotta 
should  always  be  set  in  either  natural  cement  or  Portland  cement, 
mixed  with  sand,  and  in  about  the  same  way  as  stone  is  set. 
As  soon  as  set,  the  outside  of  the  joints  should  be  raked  out  to  a 
depth  of  ^  of  an  inch  to  allow  for  pointing  and  to  prevent  chip- 
ping. The  terra-cotta  should  be  built  up  in  advance  of  the  backing, 
one  course  at  a  time,  and  all  voids  except  those  projecting  beyond 
the  face  of  the  wall  should  be  filled  with  grout  or  mortar,  into 
which  bricks  should  be  forced  to  make  the  work  as  solid  as  pos- 
sible. All  blocks  not  solidly  built  into  the  walls  should  be  anchored 
'with  galvanized-iron  clamps,  the  same  as  described  for  stonework, 
and,  as  a  rule,  all  projecting  members  over  6  inches  in  height  should 
be  anchored  in  this  way. 

Terra-cotta  work  is  generally  set  by  the  brick-mason,  but  the 
specifications  should  distinctly  state  ,who  is  to  do  the  setting  and 
pointing. 

Much  better  results  are  always  obtained  when  the  setting  of  the 
terra-cotta  is  included  in  the  terra-cotta  contract  and  is  done  by  the 
manufacturer,  as  it  is  to  his  advantage  to  take  the  greatest  care  to 
satisfactorily  erect  the  material. 

Pointing. — After  the  walls  are  up  the  joints  should  be  pointed 
with  Portland  cement  colored  with  a  mineral  pigment  to  correspond 
with  the  color  of  the  terra-cotta.  The  pointing  is  done  in  the  same 
way  as  described  for  stone,  except  that  the  horizontal  joints  in  all 
sills  and  washes  of  belt-courses  and  cornices,  unless  covered  with 
a  roll,  should  be  raked  out  about  2  inches  deep,  calked  with  oakum 
for  about  i  inch  and  then  filled  with  an  elastic  cement. 

393.  TIME. — One  of  the  principal  objections  to  the  use  of 
terra-cotta  is  the  time  required  to  obtain  it,  especially  when  the 
building  is  some  distance  from  the  manufactory.  About  six  weeks 
are  required  for  the  production  of  terra-cotta  of  the  ordinary  kind, 
and  the  architect  should  see  that  all  the  drawings  for  the  terra- 
cotta work  are  completed  and  delivered  to  the  maker  at  as  early 
a  stage  in  the  work  as  possible,  so  that  he  may  have  ample  time 
to  produce  it. 

This  will  obviate  any  delay  if  the  architect's  drawings  and  in- 


422 


BUILDING  CONSTRUCTION.  (Ch.VIII) 


structions  are  clear,  distinct  and  complete,  as  it  takes  longer  to 
obtain  the  steel  construction  work  than  it  does  to  make  the  terra- 
cotta. 

Most  of  the  delay  in  obtaining  terra-cotta  is  really  due  to  the  fact 
that  prompt  and  careful  attention  is  not  always  given  to  the  prepara- 
tion of  the  terra-cotta  drawings  and  instructions. 

Small  pieces  of  terra-cotta  may  sometimes  be  obtained  within  two 
weeks  from  the  receipt  of  the  order,  when  the  molds  are  already 
on  hand.  It  is  always  more  expensive,  however,  to  attempt  to  turn 
out  work  in  such  short  order,  and  inexpedient  on  account  of  the 
risks  in  forcing  the  drying. 

394.  COST  OF  TERRA-COTTA.— Terra-cotta  is  generally 
less  expensive  than  stone,  and  ornamental  work  costs  in  stone 
about  three  times  as  much  as  it  does  in  terra-cotta. 

Being  lighter  in  weight  the  freight  charges  are  less. 

In  large  buildings  the  use  of  terra-cotta  reduces  the  cost  of  the 
steel  construction,  because  when  it  is  used  on  the  exterior  the  steel 
may  be  about  one-third  smaller  and  lighter,  thereby  reducing  the 
cost  proportionately.  This  saving  is  an  important  item  in  large 
structures.  The  cost  of  erecting  terra-cotta  is  less  than  that  of 
erecting  stone,  two  stories  of  an  all  terra-cotta  exterior  being  some- 
times put  in  place  in  the  same  time  that  it  takes  to  set  one  story  of 
stone. 

The  advantage  in  point  of  cost  in  favor  of  terra-cotta  is  greatly 
increased  if  there  is  a  large  proportion  of  molded  work,  and  espe- 
cially if  the  moldings  are  enriched  or  if  there  are  a  number  of 
ornamental  panels,  carved  capitals,  etc. 

The  use  of  terra-cotta  for  trimmings,  and  especially  for  heavy 
cornices,  in  place  of  stone,  often  reduces  the  cost  of  the*  walls  and 
foundations,  as  the  weight  of  the  terra-cotta  will  be  much  less  than 
that  of  stone,  and  the  walls  and  foundations  may  be  made  lighter 
in  consequence. 

395.  WEIGHT  AND  STRENGTH.— The  weight  of  terra- 
cotta in  solid  blocks  averages  122  pounds  per  cubic  foot.  When 
made  in  hollow  blocks  ijA  inches  thick  the  weight  varies  from  65 
to  85  pounds  per  cubic  foot,  the  smaller  pieces  weighing  the  most. 
For  pieces  12  by  18  inches  or  larger  on  the  face,  70  pounds  per 
cubic  foot  should  be  a  fair  average. 

The  crushing  strength  of  terra-cotta  blocks  in  2-inch  cubes  varies 
from  5,000  to  7,000  pounds  per  square  inch. 


ARCHITECTURAL  TERRA-COTTA. 


Hollow  blocks  of  terra-cotta,  i  foot  high,  unfilled,  have  sustained 
i86  tons  per  square  foot. 

From  these  and  other  tests  the  author  would  place  the  safe 
working  strength  of  terra-cotta  blocks  in  the  wall  at  5  tons  per 
square  foot  when  unfilled  and  at  10.  tons  per  square  foot  when 
filled  solid  with  brickwork  or  concrete. 

If  it  is  desired  to  test  the  strength  of  special  pieces,  two  or  three 
small  pieces  should  be  broken  from  the  blocks  and  ground  to  i-inch 
cubes,  and  then  tested  in  a  machine.  Should  the  average  results  fall 
much  below  6,000  pounds  the  material  should  be  rejected. 


-  Refle:<:te.d    Plan  - 


Fig.  257.    Terra-cotta  Cornice,  Church  of  Christ  Scientist,  Los  Angeles,  California. 

Transverse  Strength  of  Modillions. — A  cornice  modillion  measur- 
ing 11^  inches  high  and  8  inches  wide  at  the  wall  line,  with  a  pro- 
jection of  2  feet,  carried  a  load  of  4,083  pounds  without  injury.  A 
similar  modillion  inches  high,  6  inches  wide,  with  a  projection 
of  14  inches,  broke  under  2,650  pounds.  Another  bracket  from  the 
same  mold,  inserted  in  the  same  hole,  sustained  2,400  pounds  with- 
out breaking. 

396.  PROTECTION. — The  carpenter's  specifications  should 
provide  for  boxing  all  molded  and  ornamental  work  with  rough 


424  BUILDING  CONSTRUCTION.  '(Ch.VIII);; 


NB-VficN  PRO.'t.  TioN  OrCowNicr 
r.xcr.cDS        "fvo  Oi'r:vrT.->  in 
VASn  WiLU  Dr.  KcciviBCD  in sirAP  Oi" 
Own  A3  5110VN  AT  'c' 


5i<vi-TC«  3now:NO  'METtiOD  or 
ANCtioRiNO  Small  CORNICES  no  t  no 

Fig.  258.     Typical  Terra-cotta  Cornices  for  Skeleton  Construction. 


pine  boards  to  guard  against  damage  during  construction.  Hem- 
lock is  unsuited  for  this  purpose,  as  it  is  liable  to  stain  the  terra- 
cotta. 

397.  EXAMPLES  OF  TERRA-COTTA  CONSTRUCTION. 
— Cornices. — Where  buildings  are  trimmed  with  terra-cotta  the 
cornice  is  generally  made  of  the  same  material.  For  cornices  hav- 
ing considerable  projection  terra-cotta  possesses  the  advantages  over 


ARCHITECTURAL  TERRA-COTTA, 


425 


stone  of  being  much  lighter,  thus  permitting  a  lighter  wall  and 
steel  construction,  and  in  all  cases  it  is  much  less  expensive.  With 
stone  cornices  it  is  necessary  that  the  various  pieces  be  of  sufficient 
depth  to  balance  on  the  wall.  With  terra-cotta  cornices,  however, 
this  is  not  customary,  the  various  pieces  being  made  to  build  into 
the  wall  from  four  to  twelve  inches,  or  to  be  supported  by  iron 
work.  Generally  small  angle-irons  placed  back  to  back  and  form- 
ing a  T,  but  with  a  space  of  one  inch  between  them,  are  used  as 
outlookers  to  support  the  soffit  course,  and  also  the  modillions, 
which  are  held  up  by  hangers  which  catch  a  pipe  extending  the 
full  length  of  a  modillion.  W^here  the  projection  is  great  enough 
to  overbalance  the  weight  of  the  masonry  on  the  built-in  end,  allow- 
ing for  the  weight  of  snow  on  the  projection,  the  inner  end  of  the 
outlooker  must  be  anchored  down  by  a  continuous  channel  or 
angle,  bolted  every  few  feet  to  the  wall  by  rods,  carried  down  into 
the  wall  until  the  weight  of  the  masonry  above  the  anchor  is  ample 
to  counteract  the  leverage  of  the  projection.  Unless  the  wall  is 
very  heavy,  it  is  also  advisable  to  anchor  the  top  of  the  wall  to  the 
roof  chimneys  to  prevent  its  inclining  outward.  An  illustration  of 
this  method  of  construction  is  given  in  Fig.  257,  which  shows  sec- 
tions, plan  and  elevation  of  a  cornice  built  by  the  Atlantic  Terra- 
cotta Company  for  the  Church  of  Christ  Scientist,  Los  Angeies, 
California. 

Fig.  258*  shows  sortlfe  examples  of  typical  terra-cotta  cornice  con- 
struction used  with  skeleton-frame  buildings,  with  all  details. 

These  sections  are  of  very  recent  and  up-to-date  work,  and  may 
be  taken  as  models  of  good  economical  construction  in  terra-cotta 
where  a  heavy  projection  is  required.  When  a  cornice  is  supported 
by  iron  work,  the  method  of  anchoring  must  be  decided  before  the 
work  is  made,  as  provision  must  be  made  in  the  blocks  for  inserting 
the  beams  or  anchors;  and  a  copy  of  the  steel  drawings  should  be 
furnished  the  manufacturer  to  enable  him  to  get  out  his  part  of  the 
work  correctly.  All  of  this  steel  work  should  be  so  designed  that 
it  is  adjustable,  as  the  inaccuracies  of  building  are  such  that  if  the 
positions  of  the  iron  are  fixed  they  will  sometimes  be  at  variance 
with  the  provisions  for  the  terra-cotta. 

Pediments. — Fig.  259*  shows  terra-cotta  pediment  and  cornice 
detail  construction,  with  entire  entablature,  and  with  plan,  of  soffit, 
elevations  and  sections  of  returns  and  corner  supports. 

*  Courtesy  of  the  Northwestern  Terra-cotta  Company,  Chicago. 


426 


BUILDING  CONSTRUCTION.  (Cn.VIin 


PEDIMCNT  DETA1L5 
5nOWlNO 

ARcniTRAvc  ^  sorriT 
Support  at  corncrs 
Typical  cornicc  vnn 
Rakd  ^  outtcr. 

SCAl-C  lllllllflllllllllll  I— J=         I  I  rtCT 


LLCVATI^ON  or  RCTURK 


o 

o 

SCGTION  AA 


Plan  Lookiisto  L/p 


Fig.  259.— Terra-cotta  Pediments  and  Cornice  Details. 


ARCHITECTURAL  TERRA-COTTA,  427 


RETURN' 


Front  LLCVAnoN 


5ncTios  or  ikos  Support 
yvTCoKstK.  On  llmc  aa. 


."^CCTION 


Plan  Looklmo  Up 


DCTA1L5  or  CORNICE  ^BALU5TRADQ 
t^xMiMiWiil'dbj  5  nOWl  NO  tebtMsMitcMiJj 
CORNER  CONSTRUCTION 
SUPPORT  or  MODILLION5 
&  CONSTRUCTION  Or 

Balustcr.  Rail 

I'^'-rM  i-i|Viliiii*  iiL,!   -  . — 1 — ■      I         I         (■.!■■  J  i  Ir-rt 


Fig.  260. — Terra-cotta  Balustrade  and  Cornice  Details. 


428 


BUILDING  CONSTRUCTION.        (Ch.  VIII) 


rXoNT  Elevation  6idlVicw    Plan  or  5tccl  T^amc 


Fig.  261. — Terra-cotta  Balcony  Details. 


ARCHITECTURAL  TERRA-COTTA. 


429 


430 


BUILDING  CONSTRUCTION.  (Ch.VIII) 


Fig.  263. — Terra-cotta  Vaulted  Ceiling,  Union  Station,  Washington,  D.  C. 


ARCHITECTURAL  TERRA-COTTA. 


Balustrades. — Fig.  260*  shows  terra-cotta  balustrade  and  cornice 
detail  construction,  with  modillion  and  corner  supports,  plan  of 
cornice  soffit,  return,  section,  detail  construction  of  balustrade  posts 
or  pedestals,  rails,  balusters,  etc. 

Balconies. — Fig.  261'''  shows  terra-cotta  balcony  detail  construc- 
tion, with  plan  of  the  steel-supporting  frame,  sections  through  rails 
and  balusters,  isometric  perspectives  and  sections  through  the  plat- 
form, pedestals,  brackets  and  steel  supports. 

Domes. — Fig.  262t  shows  the  construction  of  the  domes  for  the 
First  Church  of  Christ  Scientist  in  Boston,  Mass.,  Charles  Brigham, 
architect. 

Terra-cotta  is  an  excellent  material  for  the  exterior  of  domes, 
because  it  is  light  in  weight ;  and  being  impervious  to  water,  makes 
a  water-tight  roof  which  will  protect  valuable  mural  decorations  in 
the  interior.  Elaborate  and  satisfactory  results  may  be  obtained  in 
polychrome  glazes  at  a  comparatively  slight  additional  cost.  This 
plate  shows  the  construction  of  a  terra-cotta  dome,  carried  on  an 
iron  framework,  allowing  ample  air-space  between  the  terra-cotta 
and  the  inner  concrete  dome  to  allow  evaporation  of  any  moisture 
which  might  possibly  collect  under  the  terra-cotta. 

Vaulted  Ceilings.— Fig.  263t  shows  the  construction  of  one  of 
the  vaulted  ceilings  built  in  the  Union  Station  at  Washington, 
D.  C.,  D.  H.  Burnham  &  Company,  architects. 

For  vaulted  ceilings  also  terra-cotta  is  an  excellent  material,  not 
only  because  of  its  light  weight,  but  because,  being  hollow,  it  afifoi^ds 
space  for  a  monolithic  backing  of  concrete,  which  may  be  rein- 
forced with  steel  to  carry  any  load  necessary.  Very  large  spans, 
may  be  safely  carried  in  this  manner  with  an  economical  expendi- 
ture of  materials  which  in  themselves  are  not  expensive. 

The  figure  shows  a  panelled  vault  which,  if  built  of  stone,  and 
with  the  same  design  and  ornamentation,  would  cost  many  times 
as  much. 

Terra-cotta  Facing  for  Reinforced  Concrete. — The  method  of 
attaching  terra-cotta  facing  to  reinforced  concrete  walls  is  shown  in 
Fig.  264.1  The  anchors  are  built  into  the  forms  before  the  con- 
crete is  poured.  When  the  concrete  is  hard  the  position  of  these 
anchors  is  fixed  ;  therefore  there  must  be  some  method  of  adjust- 
ment in  atta,ching  them  to  the  terra-cotta.    This  is  arranged  by 


*  Courtesy  of  the  Northwestern  Terra-cotta  Company,  Chicago, 
t  Courtesy  of  tJic  Atlantic  Terra-cotta  Comi)any,  New  York. 


ARCHITECTURAL  TERRA-COTTA, 


Fig.  265. — Terra-cotta  Facing  for  Light-courts. 


434 


BUILDING  CONSTRUCTION.  (Ch.VIII) 


placing  rods  in  holes  provided  in  the  terra-cotta  and  bending  the 
anchors  around  these  rods  wherever  they  come  in  contact.  Another 
method  is  to  place  continuous  rods  against  the  walls  and  bend  the 
anchors  around  them,  wrapping  copper  wire  around  these  rods, 
and  tying  them  to  the  rod  in  the  terra-cotta.  The  concrete  may  be 
molded  so  as  to  form  shelves  for  the  support  of  projecting  cor- 
nices, and  pipes  may  be  placed  in  the  walls  as  anchor  holes  through 
v^hich  to  pass  bolts  or  rods  where  necessary.  The  terra-cotta 
facing  after  being  attached  should  have  the  voids  at  the  back  filled 
with  mortar  or  cement. 

Light-courts. — Fig.  265''^  shows  a  treatment  for  the  light-courts 
of  large  office-buildings  or  apartment-houses.  The  great  advan- 
tages of  terra-cotta  for  such  purposes  are  now  recognized.  It 
absorbs  no  dirt  from  the  atmosphere,  washing  clean  after  a 
storm.  The  enduring  white  color  reflects  the  light,  adding 
materially  to  the  amount  obtained.  The  figure  shows  a  conven- 
tional treatment  of  ashlar  facing  with  sills  and  cornice,  showing 
proper  methods  of  construction  and  anchoring. 

398.  FIRE-RESISTANCE  OF  TERRA-COTTA.— Architec- 
tural terra-cotta,  being  made  of  clay,  and  burned  to  a  high  tem- 
perature, offers  the  same  resistance  to  fire  as  terra-cotta  fire-proofing. 
This  fact  was  demonstrated  during  the  Baltimore  and  San  Fran- 
cisco fires,  where  buildings  constructed  of  this  material  showed 
great  resistance  to  the  disastrous  conflagration.  In  the  case  of 
the  Union  Trust  Building  in  Baltimore,  constructed  with  architec- 
tural terra-cotta  exterior  wall-facing  and  terra-cotta  fire-proofing 
interior,  although  all .  inflammable  materials  in  the  building  were 
consumed,  these  building  materials  protected  the  constructional 
steel  to  such  an  extent  that  while  the  architectural  terra-cotta  was 
badly  stained  by  smoke  and  was  renewed  on  this  account,  the  steel 
frame  was  virtually  unharmed. 

In  some  cases  where  the  buildings  were  constructed  of  stone  it 
was  necessary  to  take  down  the  steel  frames  which  were  badly 
warped  and  weakened. 

The  Fairmont  Hotel,  in  San  Francisco,  is  another  instance  dem- 
onstrating the  fire-resisting  qualities  of  terra-cotta.  Although  in 
the  middle  of  the  burned  area,  most  of  the  damage  to  the  building 
was  caused  by  the  earthquake  and  by  the  smoke  stains  on  the  terra- 
cotta. 

*  CourtesS'  of  the  Atlantic  Terra-cotta  Company,  New  York. 


Chapter  IX. 

Fire-proofing  of  Buildings. 


I.  INTRODUCTION. 

399.  GENERAL  CONSIDERATIONS.— Most  of  the  materials 
employed  for  protecting  the  structural  portions  of  buildings  from 
fire  and  heat,  and  for  filling  between  the  floor  beams  and  rafters, 
are  of  earthy  composition  arid  come  within  the  province  of  the  mason 
or  plasterer. 

The  constructive  fire-proof  materials,  that  is,  those  which  have  to 
support  any  weight,  most  extensively  used  in  this  country  are 
dense  hollow  tiles,  porous  terra-cotta  tiles  or  blocks  and  various  con- 
crete compositions  generally  combined  with  steel  in  the  shape  of 
small  bars,  wires  or  netting.  These  materials  are  used  in  different 
forms  and  in  different  ways,  and  many  of  them  are  covered  by 
patents  controlled  by  large  manufacturing  corporations.  Some  of 
these  manufacturing  corporations  used  to  take  contracts  to  furnish 
all  the  fire-proofing  material  required  in  a  building  and  to  put  it 
in  place,  leaving  the  building  ready  for  the  plasterer  and  carpenter. 
They  now  generally  confine  their  business  to  manufacturing  the 
material.  There,  are,  however,  in  the  case  of  reinforced  concrete 
construction,  fire-proofing  companies  that  estimate  from  the  archi- 
ect's  drawings  and  give  a  lump-sum  price  for  the  total  reinforce- 
ment of  a  building,  set  in  place  in  the  forms ;  and  in  the  case  of  tile 
or  terra-cotta  fire-proofing  and  fire-proof  construction,  companies 
that  are  prepared  to  execute  entire  fire-proofing  contracts. 

The  kind  of  material  and  method  of  fire-proofing  that  is  to  be 
employed  should  be  decided  upon  before  the  framing  plans  are  made, 
as  the  details  of  framing  dififer  with  different  systems.  Some  sys- 
tems also  effect  a  sufficient  saving  in  dead  weight  to  enable  lighter 
beams  and  columns  to  be  used  than  are  required  with  heavier 
systems. 

If  competitive  bids  are  desired  to  assist  in  determining  the  kind  of 
fire-proofing  to  be  employed,  they  can  often  be  obtained  before  the 


435 


436 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


plans  are  completed,  the  position  of  the  columns  determining  the 
spans  and  widths  of  arches. 

In  the  case  of  terra-cotta  tile  floor  arch  construction,  if  it  is  decided 
to  use  either  porous  or  dense  tile  arches,  it  is  not  absolutely  neces- 
sary to  specify  any  particular  make  of  tile,  the  specifications  being 
written  so  that  any  tile  which  fulfils  the  conditions  therein  contained 
may  be  used. 

The  subject  of  fire-proof  construction  has  received  a  great  deal  of 
attention  during  the  past  few  years,  and  the  increased  demand  for  a 
safe  and  economical  system  of  fire-proofing  has  led  to  the  introduc- 
tion of  many  systems,  some  of  which,  however,  may  be  said  to  be 
still  in  the  experimental  stage.  A  great  many  tests  have  been  made 
of  the  various  physical  properties  of  different  materials  used  in  con- 
nection with  the  fire-proofing  of  buildings.  As  it  is  not  the  purpose 
of  this  book  to  enter  extensively  into  the  subject  of  the  strength  of 
materials,  but  rather  to  describe  methods  of  construction,  we  shall 
here  undertake  to  describe  only  those  methods  of  fire-proofing  in 
vogue  in  this  country,  referring  the  reader  to  the  author's  ''Pocket- 
Book,"  and  to  records  of  various  tests  published  in  the  different 
journals  and  government  publications  for  more  complete  data. 

A  careful  comparison  of  the  cost  per  cubic  foot  of  a  large  num- 
ber of  buildings  estimated  for  both  fire-proof  and  ordinary  construc- 
tion seems  to  indicate  that  the  cost  of  the  fire-proof  construction  is 
from  9  to  13  per  cent  greater  than  that  of  the  wooden-joist  con- 
struction ;  and  that,  in  the  case  of  such  buildings  as  stores  and 
warehouses,  as  small  an  amount  as  5  per  cent  will  cover  the  differ- 
ence in  cost.'^ 

400.  VARIOUS  DEFINITIONS  OF  FIRE-PROOFING.— 
The  building  codes  of  the  different  cities  carefully  define  what  is 
meant  by  the  term  "fire-proof  construction."  They  differ  in  word- 
ing and  also  in  some  details  of  requirements,  but  there  is  a  con- 
stantly increasing  tendency  toward  uniformity  both  in  the  matter 
and  in  the  form  of  these  laws  and  ordinances. 

The  codes  of  the  smaller  cities  are  in  many  cases  based  upon,  or 
follow  closely,  those  of  the  largest  cities  and  it  will  be  sufficient  to 
quote  from  the  laws  of  the  three  largest  cities,  New  York,  Chicago 
and  Philadelphia. 


*  For  cost  of  buildings  per  cubic  foot  and  per  square  foot,  etc.,  see  the  "Architect's 
and  Builder's  Pocket-Book,"  by  Frank  E.    Kidder.    Part  III. 


FIRE-PROOFING— INTRODUCTION. 


437 


The  New  York  Definition  of  Fire-proof  Construction. — The 
Building-  Code  of  the  City  of  New  York  requires  that  buildings  which 
are  to  be  classed  as  "fire-proof  shall  be  "constructed  with  walls  of 
brick,  stone,  Portland  cement  concrete,  iron  or  steel,  in  which  wood 
beams  or  lintels  shall  not  be  placed,  and  in  which  the  floors  and  roof 
shall  be  of  materials  provided  for  in  Section  io6  of  this  Code.  The 
stairs  and  staircase  landings  shall  be  built  entirely  of  brick,  stone. 
Portland  cement  concrete,  iron  or  steel.  No  woodwork  or  other 
inflammable  material  shall  be  used  in  any  of  the  partitions,  floorings 
or  ceilings  in  any  such  fire-proof  buildings,  excepting,  however,  that 
w^hen  the  height  of  the  building  does  not  exceed  twelve  stories  nor 
more  than  one  hundred  and  fifty  feet,  the  doors  and  windows  and 
their  frames,  the  trims,  the  casings,  the  interior  finish  (when  filled 
solid  at  the  back  with  fire-proof  material),  and  the  floor  boards  and 
sleepers  directly  thereunder,  may  be  of  wood,  but  the  space  between 
the  sleepers  shall  be  solidly  filled  with  fire-proof  materials  and  extend 
up  to  the  under  side  of  the  floor  boards. 

'When  the  height  of  a  fire-proof  building  exceeds  twelve  stories, 
or  more  than  one  hundred  and  fifty  feet,  the  floor  surface  shall  be 
of  stone,  cement,  rock  or  asphalt,  tiling  or  similar  incombustible 
material,  or  the  sleepers  and  floors  may  be  of  wood  treated  by  some 
process,  approved  by  the  Board  of  Buildings,  to  render  the  same 
fire-proof.  All  outside  window  frames  and  sash  shall  be  of  metal, 
or  wood  covered  with  metal.  The  inside  window  frames  and  sash, 
doors,  trim  and  other  interior  finish  may  be  of  wood  covered  with 
metal,  or  wood  treated  by  some  process  approved  by  the  Board  of 
Buildings  to  render  the  same  fire-proof. 

''All  hall  partitions  or  permanent  partitions  between  rooms  in  fire- 
proof buildings  shall  be  built  of  fire-proof  material  and  shall  not 
be  started  on  wood  sills,  nor  on  wood  floor  boards,  but  be  built  upon 
the  fire-proof  construction  of  the  floor  and  extend  to  the  fire-proof 
beam  filling  above.  The  tops  of  all  door  and  window  openings  in 
such  partitions  shall  be  at  least  twelve  inches  below  the. ceiling  line." 

The  Section  io6  referred  to  above  has  reference  to  the  subject 
of  "fire-proof  floors,"  and  the  Code  permits  them  to  be  constructed 
of  any  materials  successfully  standing  the  tests  prescribed,  such  as 
brick,  tile,  cement  concrete,  etc. 

The  Chicago  Definition  of  Fire-proof  Construction. — In  the 
article  on  "Fire-proof  Construction"  in  the  "Revised  Municipal 


438 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


Code  Governing  the  Erection  of  Buildings,"  the  following  definition 
is  given :  ''The  term  fire-proof  construction  shall  apply  to  all  build- 
ings in  which  all  parts  that  carry  weights  or  resist  strains,  and  also 
all  exterior  walls  and  all  interior  walls  and  all  interior  partitions  and 
all  stairways  and  all  elevator  enclosures  are  made  entirely  of  incom- 
bustible material,  and  in  which  all  metallic  structural  members  are 
protected  against  the  effects  of  fire  by  coverings  of  a  material  which 
shall  be  entirely  incombustible,  and  a  slow  heat  conductor,  and  here- 
inafter termed  'fire-proofing  material.'  Reinforced  concrete  as  de- 
fined in  this  ordinance  shall  be  considered  fire-proof  construction. 

"The  materials  which  shall  be  considered  as  filling  the  conditions 
of  fire-proof  covering  are :  first,  burnt  brick ;  second,  tiles  of  burnt 
clay;  third,  approved  cement  concrete;  fourth,  terra-cotta ;  fifth, 
approved  cinder  concrete." 

The  Philadelphia  Definition  of  Fire-proof  Construction. — The 
laws  and  ordinances  relating  to  the  Bureau  of  Building  Inspection 
of  Philadelphia  contain  the  following  requirements  and  the  definition 
of  fire-proof  construction : 

"Where  the  inclosing,  or  division  walls  of  a  building  are  wholly 
or  in  part  supported  on  iron  or  steel  beams,  girders  and  columns, 
such  beams,  girders  and  columns  shall  be  protected  against  the 
external  changes  of  the  atmosphere  and  against  fire  by  a  covering  of 
brick,  terra-cotta,  fire-clay,  tile,  or  other  approved  fire-proofing,  com- 
pletely enveloping  said  structural  members  of  iron  or  steel.  Said 
fire-proofing  around  outside  columns  and  beams,  if  of  brick,  shall  not 
be  less  than  eight  (8)  inches;  if  of  hollow  tile,  shall  not  be  less  than 
six  (6)  inches  thick;  and  there  shall  be  at  least  two  sets  of  air- 
spaces between  the  iron  and  steel  members  and  the  outside  of  the 
hollow  tile  covering.  In  all  cases  the  brick  or  hollow  tile  shall  be 
bedded  in  cement  mortar  close  up  to  the  iron  or.  steel  members,  and 
all  joints  shall  be  made  full  and  solid. 

"No  building  shall  be  deemed  a  fire-proof  building  unless,  in 
addition  to  the  above  required  covering  of  the  iron  or  steel  mem- 
bers, all  the  interior  columns,  beams  and  girders  be  enveloped  in 
such  fire-resisting  materials  as  shall  be  approved  by  the  Bureau  of 
Building  Inspection." 

401.  CONDITIONS  LIMITING  THE  HEIGHTS  AND 
AREAS  OF  NON-FIRE-PROOF  BUILDINGS.— On  account  of 
the  difficulties  met  with  in  dealing  with  fires  in  high  buildings  and 


FIRE-PROOFING— IXTRODUCTIOX,    '  439 

•  in  buildings  of  large  area  and  few  interior  division  walls,  the  build- 
ing laws  of  cities  place  limitations  upon  non-fire-proof  structures  in 
regard  to  both  their  height  and  their  floor  area. 

The  following  table  gives  the  limiting  heights  for  non-fire-proof 
buildings  for  some  of  the  larger  cities  of  the  United  States : 


TABLE  XXVIIL 
Limiting  Heights  for  Non-fire-proof  Buildings. 


City 

All 
Build- 
ings 

Hotels 

Schools 

Hospitals 

and 
Asylums 

Residence 
Buildings 

Buffalo,  N  Y  

New  York,  N.  Y    

73  ft. 
75  ft. 
75  ft. 

75  ft. 

75  ft. 
75  ft 
75  ft. 
80  ft. 

84  ft. 

85  ft. 
90  ft. 

100  ft. 

100  ft. 
100  ft. 
100  ft. 

35  ft. 

 { 

35  ft. 

2  stories 

above 
basement 

35  ft. 

2  stories 

above 
basement 

4  stories 
and 

basement 
65  ft. 
60  ft. 

3  stories 

5  stories 
and 

basement 

3  stories 

4  stories 

60  ft. 
60  ft. 

3  stories 
52  ft. 

60  ft. 
3  stories 

45  ft. 

3  stories 

3  stories 

2  stories  -| 
53  ft. 

Philadelphia,  Pa  

The  following  are  the  limiting  areas  for  non-fire-proof  buildings, 
taken  from  the  building  laws  of  the  five  largest  cities : 

LIMITING  AREAS  FOR  NON-FIRE-PROOF  BUILDINGS. 

Chicago   8,000  square  feet  on  an  interior  lot.  . 

12,500  square  feet  on  a  corner. 

22,000  square  feet  when  facing  three  streets. 
New  York  9,000  square  feet  if  of  ordinary  wood-joist  construction. 

12,000  square  feet  if  of  slow-burning  construction. 
Philadelphia  .....5,000  square  feet  if  of  ordinary  wood-joist  construction. 

15,000  square  feet  if  of  slow-burning  construction. 

St.  Louis  7,500  square  feet. 

Boston   5,000  square  feet. 

402.  DIVISIONS  OF  THE  SUBJECT.— The  subject  of  thi<5 
chapter,  'Tire-proofing  of  Buildings,"  may  be  conveniently  divided 
into  two  principal  divisions,  viz.,  Fire-proofing  Materials  and  Fire- 
proof Construction. 


440 


BUILDING  CONSTRUCTION.         (Cii.  IX) 


2.    FIRE-,PROOF  MATERIALS. 

403.  GENERAL  CONSIDERATIONS.— Various  materials 
have  been  introduced  at  different  times  for  the  purpose  of  making 
buildings  fire-proof.  Experience  has  shown,  however,  that  the  only 
pracfical  method  of  producing  a  really  fire-proof  building  is  by 
using  only  incombustible  materials  for  its  structural  parts  and  pro- 
tecting all  structural  metalwork  with  some  fire,  water  and  heat- 
resisting  material.  The  ideal  fire-proof  building  would  undoubtedly 
be  one  that  was  constructed  entirely  of  brickwork  and  terra-cotta 
or  of  heavy  approved  cement  concrete,  with  brick,  concrete  or  tile 
floors  or  roofs,  built  in  the  form  of  vaults  sprung  from  brick  piers 
and  without  the  employment  of  structural  metalwork.  Such  a 
building,  if  properly  designed  and  built,  would  withstand  the  com- 
bined action  of  all  the  elements  for  centuries.  Modern  commercial 
requirements,  however,  demand  that  the  vertical  supports  shall  be  as 
small  and  as  far  apart  as  possible,  and  that  the  floors  shall  be  thin 
and  have  level  ceilings ;  and  these  can  be  obtained  only  by  the  use 
of  metalwork. 

The  materials  that  have  been  found  to  successfully  answer  the 
purposes  of  modern  fire-proofing  are  confined  to  burned  brick,  tiles 
of  burned  clay,  terra-cotta,  approved  cement  concrete  and  cinder 
concrete. 

While  considering  the  materials  adapted  to  fire-proofing  and  to 
fire-proof  construction,  we  may  also  briefly  mention .  some,  which, 
while  they  are  frequently  used  in  very  important  buildings,  will 
not  successfully  stand  the  action  of  severe  heat. 

404.  STONE. — Granite,  sandstone,  limestone,  marble  and 
building-stones  in  general  are  unsatisfactory  materials  either  for 
fire-proofing  or  for  exterior  ornamentation  when  exposed  to  fire. 
They  all  scale  and  spall  and  are  often  so  badly  damaged  that  they 
require  entire  renewal.  In  the  recent  large  conflagrations  they  were 
found  to  be  unsuitable  for  bases,  columns,  lintels,  caps,  etc.,  or  for 
supporting  loads  in  locations  above  ground  where  they  were  exposed 
to  great  heat. 

Granite  tends  to  fly  to  pieces  or  to  explode  when  exposed  to 
flames.  It  is  generally  the  least  refractory  material  among  the 
stones  in  case  of  fire,  with  the  exception  of  the  limestones  and 
marbles,  which  frequently  meet  with  total  destruction  from  the  heat 
of  an  average  fire.    In  the  San  Francisco  fire  the  sandstone  used 


FIRE-PROOFING— MATERIALS. 


441 


for  the  fagades  of  many  of  the  buildings  generally  developed 
better  fire-resistance  than  the  granite,  but  was  still  in  many  cases 
badly  disfigured  by  moderate  heat.  The  sandstones  which  stand 
fire  with  the  least  injury  are  those  having  a  compact  and  fine- 
grained homogeneous  structure ;  but  even  these  are  seriously  inji^red 
in  the  intense  heat  of  great  conflagrations. 

405.  BRICK. — As  a  fire-proof  or  fire-resisting  material,  burned 
brick  is  vastly  superior  to  stone.  As  a  matter  of  fact,  recent  severe 
conflagrations,  like  the  San  Francisco,  Baltimore,  Rochester  and 
Toronto  fires,  proved  that  for  outside  wall  construction,  brick,  as  a 
fire-protecting  material,  is  superior  to  any  other  used. 

It  is  important  to  bear  in  mind,  however,  the  following  facts 
learned  or  confirmed  by  recent  experiences: 

(1)  Thin  brick  walls  are  more  severely  affected  by  heat  than  thick 
walls. 

(2)  Soft  or  underburned  bricks  are  more  severely  affected  by 
heat  than  hard-burned  bricks. 

(3)  Good  quality  common  brickwork  will  stand  exposure  to 
ordinary  fires  for  a  long  time. 

(4)  Good  quality  common  brickwork,  when  subjected  to  the 
long-continued  severe  heat  of  a  conflagration,  tends  to  expand  on 
the  heated  side,  often  endangering  the  stability  of  a  wall,  cracking 
the  bricks  and  sometimes  even  partially  melting  them. 

(5)  *Brick  walls  which  are  lined  with  hollow  bricks  or  porous 
furring  tiles  on  the  sides  subjected  to  great  heat  will  stand  exposure 
to  fire  without  injury  for  a  longer  time  than  similar  walls  unlined. 

406.  TILING  AND  TERRA-COTTA.— Burned  clay  has 
numerous  applications  in  incombustible  building  construction. 
Tiling  and  terra-cotta  may  be  considered  under  two  subdivisions : 

(1)  Structural  Tiling  and  Terra-cotta,^ 

(2)  Ornamental  or  Architectural  Terra-cotta. 

407.  STRUCTURAL  TILING  AND  TERRA-COTTA.— For 
the  construction  of  floors,  partitions  and  light  walls,  and  for  the 
casing  of  columns,  beams  and  girders,  the  clay  is  molded  into  hollow 
tiles  or  blocks  of  three  general  kinds : 

{a.)  Dense  tiling. 
{h.)  Porous  tiling, 
(c.)  Semi-porous  tiling. 

Dense  tiling  is  also  sometimes  called  **fire-clay  tile/'  ''hollow 


442 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


pottery,"  ''hard  tile,"  "terra-cotta,"  etc. ;  and  porous  tiling  is  some- 
times called  "porous  terra-cotta,"  ''terra-cotta  lumber,"  ''cellular 
pottery,"  "soft  tiling,"  etc. 

Dense  and  semi-porous  material  is  used  for  floor  arches ;  dense, 
semi-porous  and  porous  for  partitions  and  furring;  semi-porous  and 
porous  for  column  and  girder  covering  and  for  roof  blocks. 

The  terms  "hollow  tiling"  and  "fire-proof  tiling"  are  used  when 
they  are  referred  to  in  a  general  way. 

(a.)  Dense  Tiling. — This  is  generally  made  of  fire-clay,  combined 
with  potters'-clay,  plastic  clays  or  tough-brick  clays,  molded  by 
die6  into  the  various  hollow  forms  required  for  commercial  use. 
The  clay  is  subjected  during  its  manufacture  to  a  high  pressure 
while  in  a  moist  or  damp  state,  which  gives  the  finished  material 
great  crushing  strength.  After  drying,  the  tiles  are  burned  like 
terra-cotta  in  a  kiln,  at  a  temperature  of  from  2000°  to  2500°  Fahr. 

Dense  tiling  in  solid  blocks  is  unquestionably  stronger  than  porous 
tiling,  although  more  brittle.  When  made  from  fire-clay  it  is 
undoubtedly  a  thoroughly  fire-proof  and  non-conducting  material, 
but  it  will  not  stand  the  combined  effects  of  fire  and  cold  water  as 
well  as  the  porous  tiling.  In  outer  walls,  exposed  to  the  weather 
and  required  to  be  light,  dense  tiling  is  very  desirable.  Some  manu- 
facturers furnish  it  with  a  semi-glazed  surface  for  outer  walls  of 
buildings.  For  such  use  it  has  great  durability  and  effectually  stops 
moisture. 

In  using  dense  tiling  for  fire-proof  filling,  care  should  be  taken 
that  the  tiles  are  free  from  cracks,  sound  and  hard-burned. 

(b.)  Porous  Tiling. — This  is  formed  by  mixing  sawdust  with 
pure  clay  and  submitting  it  to  an  intense  heat,  by  the  action  of  which 
the  sawdust  is  destroyed,  leaving  the  material  light  and  porous  like 
pumice-stone.  The  toughness  of  the  clay  used  determines  the  pro- 
portion of  sawdust,  which  varies  from  25  to  35  per  cent.  When 
properly  made  it  will  not  crack  nor  break  from  unequal  heating  nor 
from  being  suddenly  cooled  by  water  when  in  a  heated  condition. 
It  can  also  be  cut  with  a  saw  or  edge-tools,  and  nails  and  screws 
can  easily  be  driven  into  it  to  secure  interior  finish,  slates,  tiles,  etc. 

For  the  successful  resistance  of  heat,  and  as  a  non-conductor,  the 
author  believes  there  is  no  building  material  equal  to  it,  especially 
when  used  in  thin  sections.  To  develop  the  above  properties  to 
the  fullest  extent,  the  blocks  should  be  manufactured  from  tough 


FIRE-PROOFING— MATERIALS. 


443 


plastic  clays  mixed  with  a  small  percentage  of  fire-clay.  This 
admixture  of  fire-clay. is  desirable  but  not  essential. 

Porous  tiles,  when  properly  made  and  burned,  should  be  compact, 
tough  and  hard  and  should  ring  when  struck  with  metal.  Poorly 
mixed  pressed  or  burned  tiles,  or  tiles  from  short  or  sandy  clays, 
present  a  ragged,  soft  and  crumbly  appearance,  and  are  not 
desirable. 

Porous  tiles  for  floor  construction,  or  for  construction  carrying 
considerable  weight,  should  be  made  with  not  less  than  i-inch 
shells ;  and  the  webs  or  partitions  dividing  the  spaces  should  be  from 
to  Js  of  an  hich  thick,  according  to  the  size  of  the  hollows. 

Porous  tiles  possess  the  advantage  over  hard  tiles  of  being 
light,  tough  and  elastic,  while  dense  tiles  are  hard  and  brittle. 

(c.)  Semi-porous  Tiling. — This  is  a  sort  of  mean  between  the 
other  two  kinds  of  structural  tiling.    Opinions  differ  somewhat  as  * 
to  the  exact  ratio  that  its  general  resisting  properties  bear  to  those 
of  the  others ;  but  some  good  authorities  believe  that  it  is  as 
efficient  as  the  standard  makes  of  porous  terra-cotta  in  resisting  fire. 

In  the  process  of  grinding,  about  20  per  cent  of  ground  coal  is 
mixed  with  the  clay,  which,  while  aiding  in  the  burning  of  the 
material,  makes  it  also  lighter  and  more  or  less  porous.  It  is 
undoubtedly  a  better  fire-resistant  than  dense  tiling.* 

408.  ORNAMENTAL  OR  ARCHITECTURAL  TERRA- 
COTTA.— Among  the  refractory  materials  used  in  the  fagades  of 
buildings,  ornamental  terra-cotta  is  one  which  ranks  high.  While 
it  did  not  stand  the  intense  heat  of  recent  severe  conflagrations  as 
well  as  did  some  pressed  silica  bricks  and  terra-cotta  bricks  made  in 
the  size  of  common  bricks,  and  while  some  which  was  made  with 
thin  shells  and  webs  failed  in  many  instances,  that  which  was  made 
and  erected  with  care,  and  which  had  shells  or  wells  2  inches  or 
more  in  thickness,  gave  very  satisfactory  results. 

It  is  considered  the  best  material  for  elaborate  or  projecting  orna- 
mentation of  buildings  intended  to  be  fire-proof,  and  a  glazed  sur- 
face adds  still  more  to  its  efficiency.  The  reconstruction  necessary 
after  subjection  to  great  heat  followed  immediately  by  water  has 
been  found  to  be  very  small  in  amount  when  compared  with  that 
required  for  other  materials,  with  the  single  exception  of  fire-brick. 


*  For  notes  on  "The  Strength  of  Terra-cotta,"  see  the  "Architect's  and  Builder's 
Pocket-Book,"  by  F.  E.  Kidder. 


444 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


409.  MORTAR. — In  all  building  construction  in  which  the  prin- 
cipal materials  used  consist  of  brick,  stone  or  terra-cotta,  whether 
the  character  of  the  construction  be  fire-proof  or  non-fire-proof,  the 
material,  rriortar,  enters  to  bind  together  the  several  units. 

In  addition  to  its  binding  properties,  and  its  properties  of  damp- 
resistance,  general  strength  and  endurance,  its  fire-resistance  may  be 
considered. 

Lime  mortar  acts  fairly  well  in  good  brick  walls  and  piers  in 
resisting  heat,  but  it  is  the  general  opinion  that  the  best  cement 
mortar  gives  superior  results. 

410.  PLASTER. — When  lime  plaster  has  been  applied  to  wire 
lath  and  subjected  to  a  high  temperature,  as  in  the  case  of  actual 
fires  in  buildings,  it  has  been  found  to  stand  in  many  cases  without 
serious  injury ;  but  some  of  the  plaster  of  the  same  walls  has  been 
washed  away  in  places  by  streams  of  water  from  the  fire  hose. 

Patent  plasters  or  hard  wall-plasters  seem  to  resist  great  heat, 
and  also  great  heat  followed  by  the  sudden  application  of  cold  water, 
as  effectively  as  do  the  lime  plasters,  when  they  arc  applied  to  metal 
lath  or  brickwork. 

There  has  been  considerable  controversy  regarding  the  question 
of  the  fire-resisting  properties  of  various  mortars  and  plasters.  Up 
to  a  certain  degree  of  temperature,  varying  with  the  composition  and 
mixture  of  mortar  or  plaster  used,  and  by  no  means  reaching  the 
maximum  temperatures  of  conflagrations,  all  such  compositions 
stand  fairly  well.  Beyond  that  each  one  is  more  or  less  seriously 
affected,  and  some  fail  entirely. 

Asbestic  Plaster. — This  is  a  plaster  made  by  mixing  with  lime- 
putty,  freshly  slacked,  a  certain  proportion  of  ''asbestic,"  a  com- 
position mined  in  Canada  and  containing  a  large  proportion  of 
asbestos. 

It  seems  to  have  successfully  withstood  severe  tests  of  fire  and 
water,  the  plaster,  in  most  cases,  remaining  in  place,  uncracked  and 
unbroken. 

It  has  been  used  in  some  important  buildings,  notably  the 
Appraisers'  warehouse  in  New  York  City,  where  it  was  applied 
to  the  concrete  or  terra-cotta  surfaces  of  the  walls,  ceilings  and 
columns  to  a  thickness  of  from  5^  to  ^  of  an  inch. 

The  recommendations  for  this  plaster  are  its  toughness,  elasticity, 
property  of  receiving  nails  without  cracking,  light  weight  of  about 


FIRE-PROOFING— MATERIALS, 


445 


half  that  of  average  cement  mortar,  fire  and  water- resistance,  and 
non-tendency  to  discoloration  from  percolating  water,  acids,  etc. 
The  greatest  objection  to  this  plaster  is  its  slow-drying  property. 

411.  PLASTER-OF-PARIS  COMPOSITIONS.— In  France  a 
composition  of  plaster  of  Paris  and  broken  bricks,  chips,  etc.,  has 
been  used  for  generations  for  forming  ceilings  between  beams,  and 
its  durability  is  there  unquestioned.  A  composition  consisting  of  5, 
parts  by  weight  of  plaster  of  Paris  and  i  part  of  wood  shavings^ 
mixed  with  sufficient  water  to  bring  the  mass  to  the  consistency  of 
a  thin  paste,  was  introduced  into  this  country  in  connection  with 
the  formerly  used  ''Metropolitan  System"  of  floor  construction.  It 
was  claimed  that  this  material  is  a  remarkable  non-conductor  of 
heat,  and  that  a  moderate  thickness  of  it  prevents  the  passage  of 
nearly  all  warmth. 

This  composition  is  much  lighter  in  weight  than  ordinary  cement 
concrete. 

When  subjected  to  a  high  temperature  these  compositions  have 
a  tendency  t^o  soften  on  their  surfaces,  and  to  wash  away  to  a  greater 
or  less  depth  when  a  stream  of  water  is  thrown  on  them. 

412.  CONCRETE. — In  connection  with  the  discussion  of  the 
fire-resisting  properties  of  concrete,  the  reader  is  'referred  also  to 
the  articles  relating  to  it,  in  Chapter  X,  ''Concrete  and  Reinforced 
Concrete  Construction." 

Stone  Concrete. — The  following  is  a  brief  summary  of  conclusions 
reached  regarding  the  action  of  stone  concrete  under  the  influence 
of  heat : 

(1)  Stone  concrete  is  a  poor  conductor,  allowing  its  heated  sur- 
face to  expand,  and  the  rest  of  its  body  to  remain  cold,  thus  causing 
cracks  or  warping  or  both  together. 

(2)  Both  the  strength  and  texture  are  apt  to  be  affected  bv  great- 
heat,  with  an  accompanying  disintegration  to  about  one  inch  in  depth, 
and  a  frequent  spalling  off  of  the  surface. 

(3)  The  surface  is  generally  washed  away  to  the  depth  of  the 
part  injuriously  affected,  when  a  powerful  stream  of  water  is  applied 
after  the  heat. 

(4)  Deleterious  effects  usually  vary  with  the  kind  of  stone  used 
in  the  aggregate.  Limestone,  under  the  action  of  heat,  is  calcined^ 
and  under  the  action  of  the  water  is  often  destroyed.  Granite  and 
gravel  tend  to  spall,  because  their  coefficient  of  expansion  is  differ- 


446 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


ent  from  that  of  the  remainder  of  the  concrete  body  and  of  the  con- 
crete as  a  whole.  Trap-rock,  on  account  of  both  its  strength  and  its 
fire-resisting  properties,  is  considered  the  best  of  the  stones  for  use 
in  the  aggregates. 

(5)  Concretes  partially  injured  by  fire  may  set  again  and  become 
hard,  if  there  is  a  gradual  cooling  ofif  of  the  surface,  and  if  no  water 
is  applied;  but  this  result  cannot  always  be  relied  upon. 

Slag  Concrete. — Some  very  satisfactory  results  have  been  obtained 
from  the  use  of  blast-furnace  slags  in  the  aggregates  of  concrete, 
as  far  as  both  the  strength  and  the  resistance  to  fire  is  concerned. 

Slag  for  concrete  work  should  be  crushed  slag,  the  size  of  the 
pieces  being  about  the  same  as  those  usually  specified  for  crushed 
stone,  and  the  material  being  free  from  sulphur  or  other  injurious 
agents,  and  hard  and  not  spongy. 

Cinder  Concrete. — Observations  made  on  the  effects  of  great  heat 
upon  concretes  have  led  to  the  conclusion  that  cinder  concrete  is  an 
excellent  fire-resisting  material.  The  objections  to  its  use  is  its  non- 
imiformity  and  consequent  variable  and  often  doubtful  strength. 

When  it  is  used  the  cinders  should  be  good  quality,  clean  steam 
cinders,  free  from  unburned  particles  of  coal,  or  at  least  containing 
not  more  than  15  per  cent  of  such  coal;  and  it  should  be  ground 
by  machinery  before  mixing. 

On  account  of  its  variable  strength,  a  high  factor  of  safety,  is 
generally  used  in  the  case  of  cinder  concrete,  one-tenth  the  breaking 
load  being  customary  in  many  cities  when  it  is  used  in  floor  con- 
struction. In  the  various  building  codes  the  unit  stresses  allowed 
for  reinforced  concrete  work  with  cinder  concrete  are  much  lower 
than  those  for  slag  concrete,  and  very  much  lower  than  those  for 
stone  or  gravel  concrete  for  flexure-compression,  shear  and  adhe- 
sion and  also  for  direct  compression. 

Care  should  always  be  taken  to  guard  against  the  tendency  toward 
the  corrosion  of  steel  encased  in  cinder  concrete. 

413.  CAST-IRON. — Buildings  in  which  unprotected  iron  or 
steel  columns  are  used  cannot  be  rated  as  fire-proof  buildings.  While 
there  are  cases  in  which  the  character  and  location  of  a  building 
and  the  character  of  its  contents  are  such  that  cast-iron  columns, 
unprotected,  would  probably  safely  withstand  any  heat  to  which 
they  would  probably  be  exposed,  it  is  nevertheless  always  best  to 
protect  such -columns  with  some  approved  covering. 


FIRE-PROOF  CONSTRUCTION— COLUMNS,  ^j,y 


The  heat  usually  generated  by  the  average  contents  of  most 
mercantile  buildings  during  a  severe  fire  is  estimated  to  be  as 
high  as  2000°  Fahr.  and  higher.  It  is  known  that  unprotected  cast- 
iron,  subjected  to  temperatures  up  to  from  1300°  to  1500°,  carrying 
heavy  loads,  and  treated  with  streams  of  cold  water  when  red-hot, 
will  stand  practically  uninjured.  After  the  temperatures  pass  these 
points,  the  columns  begin  to  fail.  Consequently  in  very  hot  fires  in 
buildings,  cast-ii:on  columns,  when  unprotected,  are  pretty  sure  to 
fail  by  breaking  or  bending. 

414.  WROUGHT-IRON  AND  STEEL.— Elaborate  fire  tests 
have  been  made  upon  wrought-iron,  steel  and  cast-iron  columns  in 
order  to  determine  the  efifect  of  great  heat  with  succeeding  cold 
water  upon  them,  and  these  have  been  naturally  supplemented  by  the 
accidental  tests  of  recent  great  conflagrations. 

Unprotected  steel  columns  bearing  heavy  loads  usually  begin  to 
fail  at  a  temperature  of  about  1100°  Fahr.,  and  with  varying  higher 
temperatures  they  expand  and  soften  sufficiently  to  bend  and  twist. 
They  should  therefore  not  be  employed,  when  unprotected,  in  fire- 
proof construction ;  and  this  was  abundantly  confirmed  in  many 
instances  by  the  Baltimore  and  San  Francisco  fires. 

415.  MISCELLANEOUS  FIRE-PROOF  MATERIALS.— 
There  are  other  fire-proof  and  fire-resisting  materials  in  addition  to 
those  that  have  been  mentioned,  such  as  wire-glass,  fire-proof 
wood,  fire-proof  paint,  etc. ;  but  as  they  do  not  belong  to  masons' 
work,  they  will  not  be  considered  here.  For  a  discussion  of  their 
properties  and  uses  the  reader  is  referred  to  the  "Architect's  and 
Builder's  Pocket-Book, "  by  Frank  E.  Kidder,  in  the  chapter  011 
"Fire-proofing  of  Buildings." 

3.  CONSTRUCTION. 

I.    COLUMN  PROTECTION. 

416.  GENERAL  CONSIDERATIONS.— The  protection  of  the 
columns,  especially  in  high  buildings,  should  be  considered  the  most 
important  part  of  the  fire-proofing.  While  the  thoroughness  of  such 
protection  is  constantly  approaching  a  more  nearly  ideal  stage,  in  too 
many  instances  in  the  past  it  has  been  neglected,  often  to  the  point 
of  danger.  The  columns  and  girders  form  the  vital  parts  of  the 
skeleton  frame,  and  the  failure  of  a  column  usually  causes  failures 
in  more  of  the  other  structural  units  than  does  the  failure  of  any- 
other  one  part. 


448 


BUILDING  CONSTRUCTION. 


(Cri,  IX) 


The  character  of  the  floor  system  chosen  usually  decides  the 
character  of  the  materials  and  the  form  of  column-protection.  If  the 
floor  system  is  one  of  concrete,  this  material  is  usually  adopted  to 
cover  the  columns  and  girders ;  while  if  the  floor  system  is  one  of 
hollow  tile,  this  material  is  usually  employed  for  cohnnn  and  girder- 
protection. 

Careful  tests  made  upon  full-sized  unprotected  steel  and  cast-iron 
columns  show  that  steel  columns  fail  at  an  average  temperature  of 
1150°  Fahr.,  and  that  cast-iron  columns  fail  at  an  average  tempera- 
ture of  1300°  Fahr.,  the  average  duration  of  such  temperatures 
being  about  50  minutes. 

The  commonest  and  cheapest  method  of  fire-proofing  interior 
columns  was  formerly  by  the  use  of  shells  of  dense  terra-cotta  sur- 
rounding the  columns,  the  separate  tiles  being  usually  clamped  or 
hooked  together,  but  not  to  the  metalwork.  This  method  did  not 
prove  altogether  successful. 

*'The  use  of  dense  tiles  is  only  to  be  recommended  when  such  tiles 
are  hollow,  wdth  a  proper  air-space  around  the  metal  column ;  and 
■even  then  experience  seems  to  show  that  the  hard  tiles  are  in  no 
way  as  satisfactory  under  great  heat  as  the  more  porous  kinds. ""^^ 

It  is  important  to  know  as  much  as  possible  regarding  the  rela- 
tive value  of  different  materials  used  as  protective  coverings,  and 
with  this  end  in  view,  careful  tests  have  been  made  of  the  con- 
ductivity of  these  materials. 

The  results  of  these  tests,  which  were  made  by  the  Bureau  of 
Buildings  of  New  York  City,  are  given  in  Table  XXIX. 

TABLE  XXIX. 
Relative  Conductivity  of  Protective  Coverings. 


Material  Under  Test 


Terra-cotta:  Dense,  hollow,  2  ins.  thick  

Terra-cotta:  Semi-porous,  solid,  2  ins.  thick  

Plaster  of  Paris  and  shavings,  2  ins.  thick  

Plaster  of  Paris  and  asbestos,  2  ins.  thick  

Plaster  of  Par  is  ^  wood  fibers,  and  infusorial  earth, 

2  ins.  thick  

Concrete  of  ground  cinders^  1  5-16  ins.  thick  

Cinder  concrete^  on  metal-lath,  2  ins.  thick  

Metal  lath  and  patent  plaster,  about  y%  in.  thick 

over  1-in.  air-space  


Temp, 
on  Face 
of  Pro- 

Temperature   of  Plate  at 
Back  of  Protective  Material 
(Degrees  Fahr.)  . 

tective 
Mate- 
rial 
°Fahr. 

Before 
Heat- 
ing 

After 
Heat- 
ing 
2  Hrs. 

Heat 
Trans- 
mission 

1700 
17U0 
1700 
1700 

75 
73 
69 
70 

223 
244 
159 
163 

148 
171 
90 
93 

1700 
1700 
1700 

72 
73 
66 

167 

363 
.248 

95 
290 
183 

1700 

76 

296 

218 

Joseph  K.  Freitag,  C.  E.,  in  Architectural  Engineering. 


FIRE-PROOF  CONSTRUCTION— COLUMXS.  449 


417.  TILE  COVERINGS.— Porous  tile  is  the  most  efficient 
material  among  the  baked-clay  products  for  thoroughly  protecting 
cast-iron  or  steel  columns  supporting  walls  or  floors.  Its  thickness 
should  be  at  least  2  inches.  The  blocks  are  often  made  with  lugs 
on  the  inside,  which  rest  against  the  column,  leaving  an  air-space 
when  required.  When  the  columns  are  square  they  are  commonly 
encased  in  square  coverings  made  of  partition  blocks  set  so  as  to 
break  joint.  When  the  corners  are  required  to  be  rounded  they  may 
be  made  so  in  the  fire-proofing  in  dififerent  ways. 

In  setting  the  covering,  long,  straight,  vertical  joints  should  be 
avoided ;  and  if  in  any  case  it  is  not  possible  to  continuously  break 
joirtt,  the  blocks  should  be  bound  together  with  metal  clips  and  by 
wrapping  with  wire  or  metal  lath. 

Figs.  266  and  267  are  photographs  of  common  types  of  round 
column  covering.  Figs.  268,  269  and  270  show  methods  of  cover- 
ing with  tile,  channel  columns,  Z-bar  columns  and  square  columns 
respectively.  Figs.  271,  272,  273  and  274  show  methods  of  covering 
round  columns,  and  Fig.  275  illustrates  one  method  of  covering  a 
column  and  pipes  together. 

Fig.  276  shows  a  round  column  with  three  sections  of  covering, 
breaking  joints,  and  with  separate  pieces  of  covering  with  inside  lugs 
and  outside  ribs  or  corrugations  for  plastering,  and  with  metal  clips. 

Fig.  277  is  an  illustration  of  the  'Tdeal''  interior  fire-proof  col- 
umns made  by  Henry  Maurer  &  Son.  They  are  round,  of  radial 
bricks,  or  of  sections  shown,  of  either  solid  or  hollow  members, 
applicable  to  any  diameter,  and  designed  to  take  the  place,  in  certain 
cases,  of  iron  or  steel  columns.  An  iron  cap  or  plate,  placed  on  top, 
distributes  the  weight,  which  may  be  very  heavy.  The  surfaces  are 
ready  for  plastering.  Courses  of  band-iron  are  used  occasionally 
between  horizontal  joints,  as  in  the  "Phoenix"  wall  construction,  and 
the  columns  may  be  further  reinforced  by  upright  steel  rods  im- 
bedded in  concrete. 

In  all  column  covering  it  is  necessary  to  secure  it  so  thoroughly 
that  it  cannot  be  displaced  by  streams  of  water  from  the  firemen's 
hose ;  and  the  efficiency  of  column  protection  of  tile  is  greatly 
increased  by  wrapping  it  with  metal  lath  before  plastering.  Two 
layers  of  tiling  or  concrete  may  be  used,  the  inner  layer  being 
wrapped  with  the  lath,  which  is  imbedded  in  the  mortar,  and  all 


450 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


Fig.   266     Tile  Covering  for  Fig.  267.    Tile  Covering  for 

Round  Column.  Round  Colurnn. 


Fig.    268.    Tile   Cov-  Fig.    269.    Tile   Cov-  Fig.     270.  Tile 

ering  for  Box-  ering    for    Z-bar  Covering  for 

column.  Column.  Square  Cast- 

iron  Col- 
umn. 


Fig.  271.    Tile  Cover- 
ing for  Round  Cast- 
iron  Column. 


Fig.  272.  Tile  Cover- 
ing for  Round  Cast- 
iron  Column. 


Fig.  273.    Tile  Cover- 
ing for  Round  Cast- 
iron  Column. 


Fig.  274.     Tile  Covering 
Furred    Out  from 
Round  Column. 


Fig.  ^     275.  Tile-covered 
Column  with  Pipe 
Space. 


Above  drawings  reproduced  through  courtesy  of  National  Fire-proofing  Company. 


FIRE-PROOF  CONSTRUCTION— COLUMNS.  451 


spaces  between  the  tiles  and  the  metal  column  being  solidly  filled 
with  cement  mortar. 

418.  CONCRETE  COVERINGS.— Iron  or  steel  colmnns  may 
be  fire-proofed  by  using  metal  furring  and  metal  lath,  and  by  either 
filling  inside  of  and  around  the  lath  with  concrete  or  plastering  on 
the  lath  and  leaving  an  air-space.  The  furring  may  be  framed  out 
to  any  desired  form  or  distance,  and  there  may  be  one  or  two  layers 
or  coverings  of  the  lath  and  plaster. 

When  concrete  is  used  it  may  be  placed  to  completely  surround 


Fig.  276.    Tile  Coverinps  for  Round  Cast- 
iron  Columns. 


and  protect  the  column,  being  poured  inside  of  a  temporary  plank 
form  built  around  it,  placed  usually  at  least  2  inches  away,  and  in 
this  case  taking  the  place  of  the  metal  lath  mentioned  above.  When 
lath  is  used  it  may  serve  both  as  a  form  to  confine  the  concrete  and 
as  a  guard  to  prevent  it  from  being  knocked  off  or  washed  away  by 
water  from  the  hose  during  a  fire. 

Concrete  protection  is  better  than  that  of  lath  and  plaster,  as  it 
serves  to  strengthen  the  column  and  prevent  corrosion.  When  a 
coating  of  liquid  cement  is  first  applied  to  the  column,  and  when 
cinder  concrete  is  used,  a  very  efficient  construction  is  obtained. 
When  the  concrete  is  put  inside  of  wooden  forms,  metal  lath  wrap- 
ping is  not  necessary,  but  is  always  an  additional  safeguard. 

Fig.  278  shows  typical  concrete  covering  for  cast-iron  columns, 


452 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


round  section,  steel  plate-and-angle  columns  and  steel  plate-and- 
channel  columns. 

Figs.  2/9  and  280  show  concrete  column  coverings  with  steel  rods 

imbedded  and  connected  by 
means  of  ties  of  hoop-iron  or 
wire  according  to  the  Henne- 
bique  system. 

Figs.  281  and  282  show 
Z-bar  columns  protected  with 
concrete  covering  after  the 
manner  suggested  by  the 
Hinchman-Renton  Fire-proof- 
ing Co. ;  Fig.  282  showing  also 
a  method  of  carrying  pipes  and 
wires  up  beside  the  column, 
and  at  the  same  time  conceal- 
ing them.  Barb-wire  is  spirally 
wound  around  the  column,  and 
a  wooden  form  is  built,  leav- 


□□ 

DD 

DD 

GO 

DD 

DD 

Fig.  2; 


Tile  Columns. 


ing  the  required  space  which  is  filled  in  solid  with  cinder  concrete, 
covering  also  the  wire.  When  the  concrete  has  set  and  the  form 
has  been  removed,  plain  wire  lath  is  wrapped  around  the  concrete 


Fig.  278.    •Concrete  Coverings  for  Different  Column  Sections. 

and  nailed  to  it,  thus  securely  holding  it  in  place.  The  column  is 
then  completed  with  any  desired  plaster  finish. 

Figs.  283,  284,  285  and  286  show  steel  box-columns  and  round 


FIRE-PROOF  CONSTRUCTION— COLUMNS. 


Fig.     279.    Concrete  Covering 
for  Columns.  Hennebique 

System. 


Fig.     280.    Concrete  Covering 
for  Column.  Hennebique 
System. 


454 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


cast-iron  columns  furred  out  for  round  and  square  concrete  pro- 
tective finish,  with  the  Reliance  Steel  Furring  made  by  the  General 
Fire-proofing  Company. 

Figs.  287  and  288  show  two  column  sections  fire-proofed  with 
concrete  and  plaster  on  wire  lath  as  suggested  by  the  Clinton  Wire 
Cloth  Company. 


Fig.    285.    Round   Cast-iron  Column.  Fig.     286.      Box-column.  All- 

Allunited   Round  Furring.  united  Round  Furring. 


419.  LATH-AND-PLASTER  COVERINGS.— As  has  been 
previously  stated,  there  are  buildings  in  which  the  columns  are  pro- 
tected by  plaster  on  metal  lath,  in  one  or  more  layers,  with  air-spaces 
between.  Two  coverings  are  much  better  than  one,  which  latter 
cannot  be  considered  a  fire-proof  construction.  Neither  is  as  good 
as  concrete.  Aside  from  the  question  of  protection  from  the  heat  of 
a  severe  fire,  there  is  always  danger  that  the  powerful  streams  of 
water  from  the  hose  will  knock  off  the  plaster. 

Figs.  289,  290,  291  and  292  show  some  column  sections  with  the 


FIRE-PROOF  CONSTRUCTION— COLUMNS.  455 


Fig.  287,    Wire  Lath  and  Concrete  Cover-       Fig.  288,    Wire  Lath  and  Concrete  Cover- 
ing  for  Column.  ing  for  Column. 


Fig.  289.    Metal  Lath  Fig.  290.    Metal  Lath 

and    Plaster    Z-bar  and    Plaster  Z-bar 

Column  Covering.  Column  Covering. 


456 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


Hinchman-Renton  fire-proofing  system  of  metal  lath  and  plaster 
coverings. 

The  Roebling'  Construction  Company  has  a  good  system  of  pro- 
tecting columns,  which  involves  furring  them  with  vertical  rods  held 
in  place  by  clamps,  and  then,  by  band-iron  laced  to  the  rods,  bending 
stiffened  wire  lath  around  and  lacing  it  to  the  furring.  The  space  is 
filled  with  concrete  and  plastered,  or  wire  lath  and  plaster'  alone  is 
used ;  but  of  course  without  the  same  security. 

Figs.  293  and  294  show  two  more  methods,  Fig.  294  being  adapted 
to  the  use  of  expanded-metal  lath. 

Figs.  .295,  296  and  297  show  various  lath-and-plaster  protective 


Fig.       293.  Column 
Coverinsr  with  Fur 
ring,  Metal  Lath 
and  Plaster. 


methods  for  columns,  suggested  by  the  White  Fire-proof  Construc- 
tion Company. 

Fig.  298  shows  the  special  lath  for  column  protection  made  by 
the  Rapp  Fire-proofing  Company.  At  the  corrugations  of  the  metal 
lath  the  plaster  finds  a  solid  bearing  against  the  column. 

Figs.  299  and  300  show  false  column  constructions  with  metal 
lath  and  plaster  coverings,  suggested  by  the  Clinton  Wire  Cloth 
Company. 

False  columns  and  pilasters  are  sometimes  necessary,  and  when 


FIRE-PROOF  CONSTRUCTION— COLUMNS.  457 


Fig.    297.    Metal    Lath    and    Plaster    Round    Column  Fig.       298.  Corrugated 

Covering.  Metal    Lath  for 

*  Column  Cover- 

ing. 


458 


BUILDING  CONSTRUCTION.  (Ch.  IX) 


Fig.  299.    False  Square  Column  with  Metal     Fig.  300.    False  Round  Column  with  Metal 
Lath  and  Plaster.  Lath  and  Plaster. 


Fig,  301. .  1  Molded  Block  and  Solid  Concrete  Column  Covering;, 


FIRE-PROOF  CONSTRUCTION— COLUMNS  459 


built  should  be  light  and  strong.  The  braces  and  the  vertical  furring 
should  be  bolted  together,  and  not  tied  with  wire. 

420.  PLASTER-BLOCK,  CONCRETE-BLOCK  AND  COM- 
POSITION-BLOCK COVERINGS.— As  a  general  rule  column 
coverings  of  this  kind  are  not  desirable,  because,  while  many  of 
them  have  good  non-conductive  properties,  it  is  often  difficult  to 


Fig.   302.    Gypsite  Tile  Column  Coverings. 


fasten  them  securely  in  place.  Those  of  plaster,  especially,  are  apt 
to  be  washed  away  by  water  from  fire  hose. 

Fig.  301  shows  the  molded  concrete-block  system  of  the  Standard 
Concrete  Steel  Company  for  column  fire-proofing.  The  blocks 
*'a"  are  molded  in  the  factory  and  there  cured  and  made  ready  to 
erect  immediately  upon  arrival  at  the  building.  They  are  made  of 
tjie  same  concrete  as  the  arches  used  in  the  floor  systems. 


Figs.  303  and  304.    Method  of  Running  Pipes  Near  Columns. 


This  same  company  has  also  a  solid  concrete  protection  for  col- 
umns placed  by  means  of  a  permanent  form  of  wire  cloth  held  in 
exact  shape  by  an  ingenious  temporary  form  until  the  concrete  has 
set.    This  also  is  shown  in  Fig.  301,  at  "b." 

Fig.  302  shows  cross-sections  of  columns  covered  with  the 
''Gypsite"  Tile  of  the  Detroit  Fire-proofing  Company,  the  first  two 
columns  being  covered  solid,  and  the  others  having  double  layers 
of  tiles  and  double  air-spaces. 


460 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


There  are  many  other  companies  making  different  compositions 
for  this  purpose. 

421.  PIPES  AND  COLUMN  FIRE-PROOFING.— It  is  gen- 
erally convenient  to  run  some  of  the  pipes  and  wires  near  the  col- 
umns as  the  latter  are  fixed  permanently  in  place,  and  as  many  parti- 
tions are  temporary  and  mov- 
able. When  possible,  these 
pipes  and  wires  should  be  run 
in  chases  in  permanent  walls ; 
but  when  they  must  be  run  up 
near  some  of  the  interior 
column-supports  they  should 
be  placed  entirely  outside  of 
the  column  fire-proof  covering, 
and  in  an  adjoining  separately 
fire-proofed  space.  Recent  con- 
flagrations   have    shown  how 

bad  the  old  construction  was,  in  which  the  pipes  were  placed  next 
to  the  column-metal  and  inside  its  fire-proofing.  In  many  cases 
their  twisting  and  buckling  threw  off  the  coverings,  exposing  the 
columns  directly  to  the  flames  and  heat. 

Figs.  303  and  304  show  two  of  several  recent  methods  employed 
for  carrying  pipes  to  higher  stories,  near  columns,  but  arranged  so 
as  not  to  endanger  them  or  their  coverings  in  case  of  any  tendency 
to  bend  or  buckle. 

See  also  Figs.  275  and  282. 

Fig.  305  shows  the  method  of  running  and  concealing  the  pipes 
in  connection  with  the  fire-proofing  of  the  columns,  which  was  used 
some  years  ago  in  the  first  eight  stories  of  the  newer  portion  of  the 
Monadnock  Building  in  Chicago. 

2.    FIRE-PROOF  FLOOR  CONSTRUCTION. 

422.  GENERAL  CONSIDERATIONS.— The  improvements  in 
fire-proof  floor  construction  have  been  many  and  they  have  been 
made  in  rapid  succession.  Previous  to  1880  so-called  fire-proof 
floors  were  constructed  of  brick  arches  turned  between  the  lower 
flanges  of  wrought-iron  I-beams.  These  arches,  with  the  concrete 
used  for  levelling,  were  very  heavy,  and  as  the  bottoms  of  the  beams 
were  unprotected  and  the  ceiling  formed  by  the  arches  very  unde- 


^TPbrousTiLe 


HoLLowBrick  in  cement 


•Fig.   305.    Column   and   Pipe   Covering  in 
Monadnocl<   Building,  Chicago. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  461 


sirable,  brick  arches  soon  gave  place  to  arches  of  hollow  dense  tile. 
The  increased  demand  for  fire-proof  construction,  taken  in  conjunc- 
tion with  the  reduction  in  the  prices  of  steel  and  fire-proofing  which 
occurred  about  the  year  1889,  led  to  many  improvements  in  the 
designs  for  hollow  tile  floor  arches,  and  als9  to  the  introduction  of 
various  systems  of  construction  based  upon  the  use  of  concrete  and 
plaster  compositions,  combined  with  steel  wires,  bars  and  cables, 
used  in  different  shapes  and  in  different  ways ;  the  chief  aim  of  the 
inventors  or  designers  being  to  secure  the  lightest  and  most  eco- 
nomical floor  consistent  with  ample  strength  and  thorough  fire- 
protection. 

In  the  following  pages  the#author  has  endeavored  to  give  an 
impartial  description  of  most  of  the  characteristic  and  leading  types 
at  present  approved  by  leading  architects  and  engineers. 

The  list  is  of  course  not  all-inclusive,  and  there  are  systems  and 
details  in  use,  which  have  most  excellent  recommendations,  but 
which  have  been  omitted  only  because  of  the  limited  space  in  a 
general  work  of  this  kind. 

423.  STANDARD  TESTS  FOR  FIRE-PROOF  FLOOR 
CONSTRUCTION. — A  greater  amount  of  study  has  been  given  ta 
fire-proof  floor  construction  than  to  any  other  parts  of  fire-proof 
buildings;  and  because  of  the  great  importance  of  the  subject, 
numerous  tests  have  been  made,  principally  under  the  auspices  of 
various  municipal  authorities.  New  York  City  has  led  in  this  in  the 
United  States ;  and  in  Europe  the  British  Fire  Prevention  Commit- 
tee, of  London,  has  added  to  our  knowledge  of  the  action  of  certain 
fire-proof  floor  constructipns  by  the  publication  of  a  number  of  tests, 
the  data  for  which,  and  also  for  tests  made  in  the  United  States, 
appear  in  recent  numbers  of  the  "Proceedings  of  the  American 
Society  for  Testing  Materials."* 

This  latter  society  has  recommended  a  standard  test  for  fire- 
proof floor  construction,  and  as  its  requirements  are  the  same  in  all 
essentials  as  those  of  some  of  the  building  codes  of  large  cities,  it  is 
given  here  as  bearing  directly  on  this  part  of  the  subject  of  the  fire- 
proofing  of  buildings : 

''The  test  structure  may  be  located  at  any  place  convenient  to  the 
applicant,  where  all  the  necessary  facilities  for  properly  conducting 
the  test  are  provided. 


^"Proceedings  of  the  Am.  Soc.  for  T.  M./'  Vol.  VI.,  p.  128. 


462 


BUILDING  CONSTRUCTION,         (Ch.  IX)' 


'The  test  structure  may  be  constructed  of  walls  of  any  material 
not  less  than  12  inches  thick,  proj)erly  buttressed  on  all  sides. 

'The  floor  construction  to  be  tested  shall  form  the  roof  of  the 
test  structure. 

''At  a  height  of  not  less  than  2  feet  6  inches,  nor  more  than  3  feet 
above  the  ground  level,  a  metal  grate,  properly  supported,  shall  be 
provided,  covering  the  whole  inside  area  of  the  building. 

"In  the  walls  below  this  grate  level,  draught  openings  shall  be 
provided,  as^  many  as  possible,  furnishing  openings  with  an  aggre- 
gate area  of  not  less  than  i  square  foot  for  every  10  square  feet  of 
grate  surface.  Means  for  temporarily  closing  these  openings  should 
be  provided. 

"In  the  wall,  immediately  above  the  grate  level,  a  firing  door,  3 
feet  6  inches  by  5  feet  high,  must  be  provided  in  the  side  of  the 
building  at  right-angles  to  the  floor  beams.  A  second  door  must  be 
added  when  the  span  of  the  floor  slab  under  test  exceeds  10  feet. 

"Flues  should  be  supplied  at  each  of  the  corners,  and  oftener  in 
^case  of  a  test-structure  exceeding  250  square  feet  of  grate  surface, 
with  sufficient  opening  to  insure  a  proper  draught,  securely  sup- 
ported and  disposed  at  the  sides  of  the  structure  in  such  manner  as 
not  to  rest  on  the  floor  under  test.  In  no  case  should  a  flue  area  be 
less  than  180  square  inches. 

"The  horizontal  dimensions  of  the  test  structure  will  depend  upon 
the  number  and  the  span  of  the  systems  under  consideration.  The 
clear  span  of  the  floor  beams  is  to  be  14  feet.  The  distance  between 
floor  beams,  or  span  of  slab,  may  be  varied  according  to  the  design 
of  the  system  to  be  tested,  and  should  be  as  near  as  possible  to  usual 
practice.  The  underside  of  the  construction  under  test  must  not  be 
less  than  9  feet  6  inches  nor  more  than  10  feet  above  the  grate  level. 

"The  construction  to  be  tested  should  be  designed  for  a  working 
load  of  one  hundred  and  fifty  pounds  per  square  foot,  and  no  more. 
This  load  to  be  uniformly  distributed  without  arching  efifect,  and  to 
be  carried  on  the  floor  during  the  fire  test. 

"The  floor  may  be  tested  as  soon  after  construction  as  desired,  but 
within  forty  days.   Artificial  drying  will  be  allowed  if  desired. 

"The  floor  is  to  be  subjected  to  the  continuous  heat  of  a  wood  fire, 
averaging  not  less  than  1700°  Fahr.  for  four  hours. 

"The  heat  obtained  shall  be  measured  by  means  of  standard  pyro- 
meters, under  the  direction  of  an  experienced  person.    The  type  of 


FIRE-PROOF  CONSTRUCTION— FLOORS.  463 


pyrometer  is  immaterial  so  long  as  its  accuracy  is  secured  by  proper 
stanclardizatioji.  The  heat  should  be  measured  at  not  less  than 
two  points  when  the  main  floor  span  is  not  more  than  10  feet,  and 
one  additional  point  when  it  exceeds  10  feet.  Temperature  readings 
at  each  point  are  to  be  taken  every  three  minutes.  The  heat  deter- 
mination shall  be  made  at  points  directly  beneath  the  floor  so  as  t6 
secure  a  fair  average. 

*'At  the  end  of  the  heat  test  a  stream  of  water  shall  be  directed 
against  the  under  side  of  the  floor,  discharged  through  a  one-and- 
'  one-eighth-inch  nozzle,  under  sixty  pounds  nozzle  pressure,  for  ten 
minutes. 

"After  the  floor  has  sufficiently  cooled,  the  load  on  the  same  shall 
be  increased  to  six  hundred  pounds  per  square  foot,  uniformly 
distributed. 

"The  test  shall  not  be  regarded  as  successful  unless  the  following 
conditions  are  met :  No  fire  nor  smoke  shall  pass  through  the  floor 
during  the  fire  test ;  the  floor  must  safely  sustain  the  loads  pre- 
scribed ;  the  permanent  deflection  must  not  exceed  one-eighth  inch 
for  each  foot  of  span  in  either  slab  or  beam." 

424.  DIVISIONS  OF  THE  SUBJECT.— The  subject  of  fire- 
proof floor  construction  may  be  conveniently  discussed  under  the 
following  divisions  and  subdivisions. 

a.  Brick  Fire-proof  Floor  Construction. 

b.  Terra-cotta  or  Tile  Fire-proof  Floor  Construction. 

1.  Segmental  Tile  Arches. 

2.  Flat  Arches,  Side-construction. 

3.  Flat  Arches,  End-construction. 

4.  Flat  Arches,  Combination  Side  and  End-construction. 

5.  Block  Tile  or  Lintel  Construction. 

6.  Flat  Tile  Construction,  Reinforced. 

7.  Guastavino  Tile  Arch  Construction. 

c.  Concrete  Fire-proof  Floor  Construction. 

1.  Segmental  Concrete  Arch  Construction. 

2.  Flat  Concrete  Construction,  Reinforced. 

3.  Sectional  Concrete  Construction. 

These  various  systems  will  be  considered  in  the  above  order,  but 
before  discussing  them  it  is  convenient  just  here  to  mention  briefly 
the  steel  framing  for  fire-proof  floors,  as  it  is  so  intimately  connected 
with  the  flooring  masonwork. 


464 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


425.  STEEL  FRAMING  FOR  FIRE-PROOF  FLOORS.— 
Two  figures  are  given,  Fig.  306,  illustrating  the  typical  steel  beam 
and  girder  floor  framing  for  long-span  construction,  and  Fig.  307, 
illustrating  the  typical  arrangement  for  short-span  construction. 

.  It  is  a  general  principle,  holding  true  with  any  kind  of  filling 
between  the  girders  and  beams,  that  for  moderate  spans  a. smaller 
amount  of  steel  is  required  than  for  very  wide  spans. 

The  system  of  fire-proof  floor  construction  is  decided  upon  before 
the  steel  framing  plans  are  made,  a  long-span  system  necessitating 


Column 


Girder 


■J6  to  20 


Girder 


Fig.  306.    Typical  Framing  for  Long-span  Conptruction. 


an  arrangement  of  the  girders  similar  to  that  shown  in  Fig.  306, 
while  an  ordinary  short  or  moderate-span  system,  such  as  the  usual 
flat  tile  arches,  necessitates  floor  beams  framed  into  the  girders  and 
spaced  at  varying  distances  apart,  ranging  from  5^  to  9  feet,  and 
similar  to  the  construction  shown  in  Fig.  307.  The  ''strut-beams" 
shown  in  Fig.  306  are  put  in  the  long-span  construction  between  the 
columns,  to  which  they  are  riveted,  and  add  to  the  rigidity  of  the 
building  both  during  and  after  its  erection. 

With  the  omission  of  the  floor  beams,  the  architect  is  restricted 
in  his  choice  of  floor  construction  to  comparatively  few  systems. 


FIRE-PROOF  CONSTRUCTION— FLOORS. 


while  a  construction  including  the  use  of  floor  beams  permits  the 
use  of  almost  any  system  of  fire-proof  floors.* 

2.  a,  BRICK  FIRE-PROOF  FLOOR  CONSTRUCTION. 
426.  GENERAL  DESCRIPTION.— Fig.  308  illustrates  the 
early  attempts  to  construct  fire-proof  floors  by  turning  brick  arches 
of  one  or  more  row-locks  from  the  lower  flanges  of  wrought-iron 
I-beams.  This  brick  construction  with  steel  beams  is  occasionally 
used  to-day,  in  such  buildings  as  warehouses  and  in  some  of  those  in 
which  the  arched  ceiling  spaces  are  not  considered  objectionable. 

.(1. 


^Column 


n 


Girder. 


Jl 


 j-  66  


Tie  Rod 


-I  


Girder 


Tie  Rod 


 i6ft 


P 


Fig.  307-    Typical  Framing  for  Short-span  Arches. 


Fig.  309  shows  the  method  of  protecting  the  lower  flanges  of  the 
beams  by  terra-cotta  skew-backs. f 

The  recommendations  for  brick  floor-arches  are  their  great 
strength  in  proportion  to  the  span,  their  resistance  to  suddenly 
applied  loads  or  severe  pounding,  and  their  elasticity  and  great 
deflection  before  failure. 


for  FU^^r  T??.,^=  ''  °V^  ?,"biects  of  "Computations  for  the  Steel  Framing,"  "Tables 
for  Floor  Beams,  "Tie-rods,"  "Load  Tests,"  etc.,  see  the  "Architect's  and  Builder's 
Pocket-Book,"  by  Frank  E.  Kidder,  Chapter  XXIII.  ^uimei  s 

t  The  construction  shown  in  Fig.  309  is  the  one  used  in  the  principal  floors  of  the 
f^rSeT'e    i^oa         Office  at  Washington,  and  is  described  in  the  EngiLeZg  Record 


466  BUILDING  CONSTRUCTION.         (Ch.  IX) 


The  objections  to  them  are  their  great  cost  when  the  increased 
expense  of  the  metal  framework  necessitated  by  their  heavy  weight 
is  inckided,  and,  for  most  buildings,  their  unsightly  appearance  as 
ceilings. 


Fig.  308.    Early  Form  of  Wrought-iron  Beam  and  Brick  Arch. 

The  following  data  will  be  found  useful  in  connection  with  this 
type  of  construction : 

Weights. — For  a  floor  similar  to  that  shown  in  Fig.  308,  from 
70  to  75  pounds  per  square  foot,  varying  with  the  weight  of 
levelling  concrete. 

Thicknesses. — For  spans  up  to  7  feet  4  inches.    For  spans  over 

7  feet,  not  less  than  8  inches.    Some  engineers  advise  a  thickness  of 

8  inches  for  spans  over  5  feet.  A  span  between  4  and  6  feet  makes 
the  most  desirable  span. 

Haunches. —  Filled  level  with  top  of  arch  with  '"wet"  cement  and 
gravel  concrete. 


Finished  Floor-, 


Tie  Rod-^ 

 ...... 

%  ^Terra-Cotta 

Fig.  309.    Brick  Floor  Arch  with  Beam  Flange  Covering. 

Rise. — One-eighth  of  the  span  or        inches  to  the  foot. 

Tie-rods."^ — Always  provided,  as  segmental  arches  exert  consid- 
erable thrust,  and  the  outer  bays,  especially,  tend  to  spread.  Spacing 
of  rods,  eight  times  the  depth  of  supporting  beam,  but  never  more 
than  8  feet.  Located  in  line  of  thrust  of  arch,  usually  below  middle 
depth  of  beam,  and  sometimes  near  bottom  flange.    Run  continu- 


*  For  a  discussion  of  the  correct  methods  of  computing  the  thrusts  of  floor  arches, 
and  of  proportioning  and  spacing  tie-rods,  see  the  "Architect's  and  Builder's  Pocket- 
Book,"  by  Frank  E.  Kidder,  Chapter  XXlll. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  467 


ously,  from  beam  to  beam,  and  when  a  steel  angle,  as  in  Fig.  308, 
is  used  instead  of  a  wall  beam  or  channel,  anchored  into  wall  with 
plate-washer,  as  shown. 

Tie-rods  are  always  desirable,  no  matter  what  system  of  tile 
arches  is  used. 

Strength. — When  thoroughly  grouted  and  levelled  with  Portland 
cement  concrete,  a  6-feet  span,  4-inch  brick  arch  will  carry  safely 
from  300  to  400  pounds  to  the  square  foot. 

Bricks. — Hard,  thoroughly  burned  common  bricks,  or  approved- 
shape  hollow  bricks. 

Manner  of  Laying  Bricks. — Laid  on  centers,  and  laid  to  a  line. 
Bricks  of  adjoining  lines  in  same  row-lock  break  joint  with  each 
other;  and  when  there  are  several  row-locks  the  joints  of  the 
adjoining  row-locks  break  joint  with  each  other.  Bricks  laid  in 
place  without  mortar,  the  joints  being  afterward  carefully  filled  full 
with  cement  grout. 

Skezv-backs. — For  unprotected  beam-flange  construction,  common 
bricks  cut  to  proper  shape,  as  in  Fig.  308 ;  for  first-class  fire-proof 
construction,  lower  flanges  of  beams  covered  with  specially  made 
terra-cotta  skew-backs,  as  in  Fig.  309. 

Brick  Floor  Construction.  Rapp  System. — This  system  combines 
the  strength  of  the  ordinary  row-lock  brick  arch  with  that  of  steel 
T-ribs,  and  an  arched  form  of  concrete  above  both. 

It  is  described  and  illustrated  under  "Segmental  Concrete  Floor 
Arches,"  in  Article  443. 

2.  b.  TERRA-COTTA  OR  TILE  FLOOR  ARCH  CONSTRUCTION. 

427.  GENERAL  CONSIDERATIONS.— The  different  kinds 
of  terra-cotta  or  tile  used  in  fire-proofing  construction  have  already 
been  mentioned  under  "Fire-proofing  Materials,"  Article  407. 

The  following  are  some  of  the  advantages  of  terra-cotta  floor 
arch  construction : 

1.  Rapidity  of  installation. 

2.  Greater  stiffening  effect  in  the  structure  against  lateral  forces, 
such  as  wind,  than  results  from  other  types  of  floor  construction.' 

3.  Supervision  necessary  during  installation  less  than  for  sys- 
tems in  which  the  materials  are  mixed  as  they  are  put  in  place. 

4.  Greater  opportunity  and  possibility  of  judging  accurately  the 
quality  of  material  used  before  and  after  setting  in  place. 

5.  Comparative  cleanliness  of  the  work  of  putting  in  place,  and 


468 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


consequent  non-interference  with  the  work  of -other  mechanics  on 
floors  below. 

The  following  are  some  of  the  disadvantages  of  terra-cotta  floor 
arch  construction : 

1.  Frequent  excess  of  weight  over  that  of  concrete  systems,  on 
account  of  necessary  concrete  filling  over  arches,  causing  increase 
of  total  cost. 

2.  Difficulty  of  adapting  systems  to  fill  spaces  of  irregular  shape. 

3.  Difficulty  and  consequent  increased  cost  of  adapting  systems 
to  varying  widths  of  spans  between  beams. 

4.  Liability  of  breakage  and  chipping  in  floor  blocks. 

5.  Greater  weakening  on  account  of  holes  for  pipes  than  that 
which  takes  place  in  monolithic  floors. 

428.  MANNER  OF  SETTING  TILE  ARCHES.— Hollow  tile 
arches  of  whatever  type  should  be  set  in  a  Portland  cement  mortar 
on  plank  centering,  slightly  cambered. 

In  warm  weather  all  tile  should  be  well  wet,  and  in  freezing 
weather  kept  dry. 

A  good  mortar  is  made  of  one  part  Portland  cement  added  to 
three  parts  rich  cold  lime,  and  one  still  better  is  made  by  mixing 
the  cement  and  sand,  and  then  adding  enough  cold  lime  putty  to 
make  it  work  smoothly.  The  use  of  hot  lime  mortar  is  never 
advised,  nor  mortar  of  cement  and  sand  alone  for  porous  hollow  tile. 

The  best  centering  for  flat  arches  is  that  in  which  the  planks  run 
at  right-angles  to  the  beams  and  rest  on  2  by  6-inch  sound  lumber 
center  pieces,  placed  midway  between  the  beams  and  extending 
parallel  with  them.  These  center  pieces  are  supported  by  T-bolts  i 
from  like  center  pieces  above,  crossing  the  beams.  The  planks  on 
which  the  tiles  are  laid  should  be  2-inch  planks,  dressed  on  one  side 
to  a  uniform  thickness  and  laid  close  together.  If  the  soffit  tiles 
are  separate  pieces  they  should  first  be  laid  directly  under  the  beams 
on  the  planking;  if  projecting  skew-backs  are  used,  they  must  first 
be  set,  after  which  the  centering  is  tightened  by  screwing  down 
the  nuts  on  the  T-bolts  until  the  soffit  tiles,  or  skew-backs,  are  hard 
against  the  beams  and  the  planking  has  a  crown  not  exceeding  ^4 
of  an  inch  in  spans  of  6  feet.  This  system  gives  what  is  very 
essential,  a  firm  and  steady  center  on  which  to  construct  the  flat 
tile  work.  The  tiles  should  be  shoved  in  place,  with  close  joints; 
and  keys  should  fit  close,  but  should  never  be  rammed  into  place. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  469 


The  centers  should  remain  from  twelve  to  thirty-six  hours,  accord- 
ing to  the  condition  of  the  weather,  the  depth  of  tiling-  and  the 
mortar  used.  In  cold  or  wet  weather  it  is  better  to  allow  48  hours 
or  even  a  still  longer  period.  When  centers  are  ''struck,"  the  ceiling 
should  be  straight,  even,  free  from  open  joints,  crevices  and  cracks 
and  ready  to  receive  the  plastering. 

Wherever  openings  are  required  through  the  floor  they  may  be 
made  by  punching  a  hole  through  the  blocks ;  or,  if  the  side-method 
arch  is  used,  a  single  block  may  be  omitted.  Small  holes  may  after- 
ward be  plugged  up  with  mortar  and  broken  pieces  of  tile. 

The  variations  in  width  of  spans  between  beams  is  provided  for 
by  supplying  tiles  of  different  sizes,  for  both  interiors  and  keys, 
thereby  securing  a  variety  of  combinations.  A  great  variety  of 
skew-backs  also  are  provided  for  fitting  different  sizes  of  beams, 

429.  PROTECTION  FROM  STAINS,  WEATHER,  ETC.— 
The  laying  of  flat  construction  in  winter  weather  without  roof  pro- 
tection should  not  be  practiced  in  climates  where  frequent  severe 
rain  and  snowstorms  are  followed  by  hard  freezing  and  thawing, 
as  the  mortar  joints  are  liable  to  be  weakened  or  ruptured,  resulting 
in  more  or  less  deflection  of  the  arches.  Porous  terra-cotta  is  liable 
to  be  utterly  ruined  if  frozen  when  water-soaked.  When  it  is 
intended  to  plaster  on  the  under  side  of  the  arches,  the  architect 
should  see  that  the  smoke  and  soot  from  the  boiler  used  for  the 
hoisting  engine  are  not  allowed  to  strike  the  arches,  as  they  are 
sure  to  stain  the  plaster,  and  as  neither  can  be  removed.  For  the 
same  reason  the  architect  should  see  that  clean  water  only  is  used 
for  mixing  the  mortar,  and  that  it  is  not  allowed  to  flow  over  the 
arches. 

Where  flat  tile  arches  have  been  used,  many  architects  have  had 
trouble  from  stains  and  efflorescence  appearing  on  the  plastered  ceil- 
ings after  the  latter  has  become  dry.  Such  stains  are  due  to  the 
efYects  of  iron  in  the  clay,  or  to  the  cinders  in  the  concrete  over 
the  arches  when  the  floors  become  very  wet,  or  to  other  causes. 
Such  stains  cannot  always  be  concealed,  even  by  oil  paint ;  and  the 
only  way  in  which  they  can  be  avoided  is  by  observing  the  above 
precautions  and  by  not  plastering  until  the  arches  are  well  dried 
out.  A  coating  of  some  one  of  the  many  hydraulic  paints  now  on 
the  market,  applied  to  the  bottom  of  the  arches  before  plastering,  is 


470 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


recommended  as  a  safe  precaution  against  stains.  Some  of  these 
paints  have  proved  very  effective. 

The  architect  should  also  see  that  the  green  arches  are  not  over- 
loaded with  building  material  by  the  other  contractors. 

430.  FLOOR  AND  CEILING  FINISH.— T/z^?  under  side  of 
flat  tile  arches  is  usually  finished  with  two  coats  of  plaster  applied 
directly  to  the  bottom  of  the  tiles.  If  there  are  inequalities  in  the 
surfaces  of  the  arches  they  should  be  filled  with  natural  cement-and- 
sand  mortar  before  plastering.  False  plaster  beams  may  be  formed 
on  metal  furring,  bolted  to  the  under  side  of  the  arches  and  covered 
with  wire  lathing,  or  the  furring  may  be  of  wood,  as  its  consump- 
tion in  case  of  fire  would  in  no  way  endanger  the  building.  Metal 
furring,  however,  is  better,  as  it  does  not  shrink. 

Wood  furring  strips  to  form  nailings  for  wood  moldings,  etc., 
may  be  secured  to  the  soffits  of  the  arches  by  punching  slot  holes  in 
the  bottom  of  the  blocks  and  inserting  T-headed  bolts. 

The  upper  surface  of  the  arches  are  generally  covered  with  con- 
crete of  a  sufficient  depth  to  allow  for  bedding  in  it  the  wooden 
strips  to  which  the  floor  boards  are  nailed. 

The  general  custom  in  regard  to  the  size  of  floor  strips  is  to  use 
strips  made  dovetail  shape,  about  21/2  inches  wide  at  the  top,  3^ 
inches  wide  at  the  bottom,  and  from  to  2  inches  thick,  and  laid 
at  right-angles  to  the  beams  and  16  inches  apart  from  centers.  The 
concrete  is  first  levelled  to  the  tops  of  the  highest  beams  and  the 
strips  then  laid  in  place  by  the  carpenter.  The  mason  thtn  fills 
between  the  strips  to  within  ^  of  an  inch  of  their  tops  with  con- 
crete pressed  down  hard  against  them.  The  flooring  is  then  nailed 
to  the  wooden  strips.  In  New  York  3  by  4-inch  strips  have  been 
used,  the  strips  being  notched  down  i  inch  over  the  beams.  The 
strips,  also,  do  not  always  run  at  right-angles  to  the  beams,  although 
the  general  opinion  appears  to  be  that  they  should  do  so  wherever 
practicable. 

The  general  custom  among  many  Western  architects  is  to  allow 
31^  inches  from  the  tops  of  the  beams  to  the  top  of  the  finished  floor. 
This  gives  a  sufficient  space  between  the  beams  and  flooring  for 
running  gas  pipes  or  water  pipes,  as  shown  in  Fig.  310.  Wherever 
buildings,  and  especially  office-buildings,  are  piped  for  gas,  it  is 
absolutely  necessary  to  leave  sufficient  space  between  the  tops  of 


FIRE-PROOF  CONSTRUCTION— FLOORS. 


471 


the  steel  beams  and  the  bottom  of  the  flooring  for  the  running  of 
branches  to  center  outlets. 

Wherever  the  nailing  strips  cross  the  floor  beams  or  girders  they 
should  be  fastened  to  them  by  means  of  iron  clamps,  made  so  that 
one  end  can  be  hooked  over  the  flange  of  the  steel  beam  and  the 
other  end  driven  into  the  side  of  the  wood  strip.  When  the  strips 
run  parallel  with  the  beams  it  is  good  practice  to  nail  pieces  of 
hoop-iron  across  the  under  sides  of  the  strips,  about  4  feet  apart, 
to  hold  .them  more  firmly  in  place,  as  concrete  alone  does  not 


K50A\ETRIC  VinW 

^     Fig.  310.     Column  Covering  and  Floor  Construction,  "Fair"  Building,  Chicago, 

hold  them  with  suflicient  firmness.  The  hoop-iron  strips  should 
be  by  ^  of  an  inch  in  section  and  10  inches  long,  and  should 
be  secured  by  two  clout  nails. 

The  concrete  used  for  the  filling  on  top  of  the  arches  should  be  a 
rich  cinder  concrete,  mixed  with  Portland  cement,  brought  level  with 
the  tops  of  the  steel  beams,  and  thoroughly  tamped.  When  the  tile 
arches  are  well  wet,  and  covered  with  this  concrete,  their  strength  is 
greatly  increased,  A  thin  coat  of  Portland  cement-and-sand  grout 
put  on  with  a  brush  should  be  applied  to  the  tops  of  the  steel  beams. 


472 


BUILDING  CONSTRUCTI'ON.         (Ch.  IX) 


after  the  nailing  strips  are  in  place ;  and  the  spaces  between  the  latter 
should  be  filled  with  a  i  to  8  or  lo  cinder  concrete.  The  concrete 
must  become  thoroughly  dry  before  the  flooring  is  laid. 

Occasionally,  where  the  beams  are  of  unusually  long  span,  a 
lo-inch  or  12-inch  arch  is  set  between  15  or  20-inch  beams.  In  such 
cases  hollow  terra-cotta  filling  blocks  may  be  used  to  fill  in  to  the 
tops  of  the  beams,  as  shown  in  Fig.  328.  Their  recommendation  is 
their  lightness  compared  with  good  concrete;  while  the  objection  to 
them  is  that  they  do  not  add  any  strength  to  the  arch  unless  care- 
fully set  in  cement  mortar,  and  unless  the  tiles  and  the  tops  of  the 
floor  arches  are  thoroughly  soaked  just  previous  to  laying  the  filling 
blocks. 

If  the  floors  are  to  be  tiled,  the  concrete  between  the  bottom  of  the 
tiles  and  the  top  of  the  arch  should  be  made  of  Portland  cement, 
sand  and  crushed  stone. 

In  the  case  of  cement-finished  floors  a  space  of  from  2^  to  3 


Wire  Lath. 

Fig.   311.    Common  .  Form   of   Segmental   Floor  Arch. 


inches  is  not  too  much  to  allow  for  the  cement  and  concrete  above 
the  steel  beams.  It  is  usually  blocked  out  in  sections  of  6  feet 
square,  or  less,  with  joints  made  to  extend  through  the  concrete; 
and,  when  possible,  the  joints  in  one  direction  are  made  to  come 
over  the  beams.  * 

Fig.  310  shows  the  floor  construction  used  in  the  'Tair"  Build- 
ing, Chicago,  Jenney  &  Mundie,  architects,  and  shows  also  the  fire- 
proofing  of  the  columns.  The  construction  shown  in  this  cut  is 
typical  of  many  other  buildings  also. 

431.  h.  I.  SEGMENTAL  TILE-FLOOR  ARCHES.— Where 
a  flat  ceiling  is  not  essential,  and  for  warehouses,  factories,  lofts,  side- 
walks, breweries,  etc.,  the  segmental  arch  gives  the  strongest,  best 
and  cheapest  (considering  the  saving  in  ironwork)  fire-proof  floor 
that  can  be  built  of  tile.    Segmental  arches  can  be  used  for  spans  up 


FIRE-PROOF  CONSTRUCTION— FLOORS.  473 


to  20  feet,  thus  dispensing  entirely  with  the  usual  floor  beams ;  but 
it  is  better  to  set  the  limit  at  about  16  feet.  They  also  efifect  a  con- 
siderable saving  in  the  dead  weight  of  the  floor,  thereby  permitting 
the  columns  and  girders  to  be  made  lighter. 

The  commonest  form  of  segmental  arch  is  that  shown  in  Fig.  311. 
It  is  made  of  hollow  blocks,  usually  4,  5,  6  or  8  inches  square 
and  12  inches  long,  the  tiles  being  laid  so  as  to  break  joint  longitud- 
inally of  the  arch,  as  shown  in  Figs.  315  and  316.  Nearly  all  manu- 
facturers of  hollow  tiling  make  one  or  more  shapes  for  segmental 
arches,  and  also  different  styles  of  skew-backs  to  use  with  them. 
These  arches  are  also  made  of  hollow  brick,  ''Haverstraw"  size.  No 
form  of  tile  floor  arch  construction  should  be  used  in  which  the 
blocks  are  single-celled.  In  driveways,  where  heavily  loaded  trucks 
and  teams  pass  over  them,  the  double  row-lock  hollow  brick  arches 
are  preferable. 

Semi-porous  segmental  tiles  usually  have  webs  from  ^  to  ^ 
of  an  inch  thick;  and  porous  tiles,  webs  }i  of  an  inch  thick,  the 
skew-back  being  %  of  an  inch  and  i  inch  thick,  respectively,  for 
the  same  materials.  Special  cases  need  greater  thicknesses.  Webs 
of  New  York  tiles  are  generally  thicker  than  those  of  Chicago  tiles,  * 
which  are  often  stronger  than  the  former. 

Hollow  tiles  for  segmental  arches  are  made  of  dense,  semi-porous 
and  porous  tiling. 

The  National  Fire-proofing  Company  states  that  ''end-construc- 
tion blocks  may  be  used,  but  they  are  unsatisfactory,  unless  the 
arches  are  of  uniform  span  and  rise  throughout.  The  rise  of  the 
side-construction  arch  can  be  varied  by  increasing  the  thickness  of 
the  upper  or  lower  part  of  the  mortar  joint;  but  this  cannot  be 
done  with  the  end-construction  method."  Figs.  312,  313,  314,  315 
and  316*  show  several  types  of  segmental  tile  floor  arches  in  general 
use.  Fig.  317  shows  photographs  of  typical  blocks.  The  large 
blocks  with  large  openings  are  lighter  and  cheaper  to  lay  than  the 
smaller  ones.  The  skew-backs  showing  rounded  surfaces  under  the 
beams  are  cheaper  to  plaster  on  than  skew-backs  with  sharp  edges. 
When  an  arch  is  raised  at  the  skew-backs  the  arch  is  flattened,  the 
dead  load  of  concrete  at  the  haunches  is  reduced,  and  the  strength 
of  the  arch  decreased. 


*  Courtesy  of  National  Fire-proofing  Co.,  Henry  Maurer  &  Son  and  Gladding, 
McBean  &  Co. 


474 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


Fig.  312,    Types  of  Skew-backs  and  Keys. 


■tig.   313-    Double   aad   Single   Row-lock  Arches.     Hollow  Bricks. 


Fig.  314.    I.  Plastered  Arch.    2.  Metal-lath  Ceiling. 


Fig.  315.    Segmental  Tile  Floor  Arch. 


FIRE-PROOF  CONSTRUCTIOX— FLOORS.  475 


The  raised  block  shown  in  Fig.  312  has  been  used  in  very  wide 
spans,  its  object  being  to  bring  the  concrete  back  of  it  into  com- 
pression, and  to  reheve  to  some  extent  the  pressure  on  the  skew- 
backs. 

Segmental  arches  should  have  a  rise  of  not  less  than  i  inch  per 


Fig.  316.    Segmental  Tile  Floor  Arch. 

foot  of  span,  and  i^/^  inches  wherever  practicable.  The  rule  is 
sometimes  given,  that  the  rise  of  the  soffit  of  the  arch  above  the 
spring  line  should  be  from  i-io  to  of  the  span.  As  the  rise 
increases,  the  thrust  decreases. 

The  considerable  thrust  of  these  arches  should  be  taken  up  by 
ample  tie-rods.  The  lower  third  of  the  beams  is  the  location  indi- 
cated for  greatest  efficiency.    But  when  placed  within  the  lower 


Fig.   317.    Typical  Tile   Skews  and  Key. 

third  of  the  beam  they  show  on  the  ceiling.  In  this  case  they  are 
either  painted  and  left  unprotected,  or  hidden  by  a  metal  lath  and 
plaster  ceiling,  or  occasionally  encased  with  a  specially  made 
tie-rod  tile. 

With  this  type  of  arch  sometimes  very  heavy  or  solid  skew-backs 
are  used  without  the  flange  projection,  as  the  thrust  on  the  skew- 
backs  is  very  great  where  an  arch  is  of  wide  span.  In  this  case  the 
bottom  flansre  of  the  beam  is  covered  with  heavv,  stiffened  wire 


476 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


lath  before  the  skew-backs  are  set.  When  plastered  the  ceiling  has 
the  appearance  shown  in  Figs.  311  and  314,  the  latter  showing,  in 
the  right  half  of  the  ilkistration,  a  very  light,  strong  arch  with  deep 
beams,  with  flat  ceiling  formed  by  using  metal  lath  and  plaster  sus- 
pended below. 

Weight  and  Strength. — The  segmental  form  of  arch  is  undoubt- 
edly the  strongest  that  can  be  built,  whether  of  brick,  hollow  tile 
or  concrete.  The  following  are  the  average  weights  for  various 
ordinary  segmental  arches : 

Solid  brick  segmental  arch,  4-inch,  38  pounds  per  square  foot. 
Solid  brick  segmental  arch,  8-inch,  80  pounds  per  square  foot. 
Hollow  brick  segmental  arch,  4-inch,  31  pounds  per  square  foot. 
Hollow  brick  segmental  arch,  8-inch,  65  pounds  per  square  foot. 
Hollow  tile  segmental  arch,  6-inch,  26  pounds  per  square  foot. 
Hollow  tile  segmental  arch,  8-inch,  32  pounds  per  square  foot. 

The  weights  of  the  flooring,  concrete,  plaster,  sleepers,  I-beams, 
etc.,  must  be  added  to  the  above  weights  in  order  to  obtain  the  total 
dead  load. 

In  the  celebrated  Austrian  tests*  a  common  brick  arch  51^  inches 
thick  and  8  feet  span,  with  a  rise  of  9.85  inches,  carried  an  eccentric 
load  of  885  pounds  per  square  foot  before  failing.  The  failure  was 
then  caused  by  buckling  and  not  by  crushing.  A  porous  tile  arch  of 
15  feet  4  inches  span,  with  a  rise  of  16  inches,  built  with  6-inch  hol- 
low blocks  for  a. distance  of  7  feet  8  inches  across  the  middle  part 
and  with  8-inch  blocks  for  the  balance,  was  tested  by  loading  one 
side  with  a  pile  of  bricks  measuring  4  feet  6  inches  lengthwise  of 
the  arch  and  7  feet  6  inches  in  the  direction  of  the  width.  When 
the  weight  reached  42,000  pounds  (1,235  pounds  per  square  foot), 
the  unloaded  side  commenced  to  buckle,  and  in  30  minutes  collapsed. f 

Complete  tables  of  the  strength  of  all  types  of  floor  arches  are 
given  in  the  various  handbooks  and  manufacturers'  catalogues,  and 
the  reader  is  referred  to  them  and  to  Kidder's  ''Architect's  and 
Builder's  Pocket-Book, "  which  contains  condensed  tables  compiled 
for  reference  in  those  cases  occurring  oftenest  in  general  practice. 

Setting. — Segmental  arches  are  set  in  the  same  way  as  flat  tile 
arches,  except  that  the  wood  centers  are  arched  to  the  desired  curve 
and  suspended  at  the  sides  by  hooks  passing  over  the  beams  or 
girders.    The  bottoms  of  the  hooks  are  made  round,  and  have  a 


*  Architecture  and  Building.  January  4,  1896. 
t  Engineering  Record,  April   14,  1894. 


FIKE-FROOF  CONSTRUCTION— FLOORS.  477 

thread  and  wing-nut  to  bring  the  center  into  its  proper  place  and 
to  lower  it  after  the  arch  has  set. 

Holes  are  left  where  the  hooks  pass  through  the  arch,  and  after 
the  centers  are  removed  these  holes  are  plugged  with  mortar  and 
pieces  of  tile. 

Good  cement  concrete  should  be  used  to  fill  the  haunches,  the  top 
surface  being  levelled  off  to  a  height  which  is  not  less  than  i  inch 
above  the  crown  of  the  arch.  Cinder  concrete  filling  may  be  used 
for  short  spans,  but  as  the  strength  of  a  floor  arch  at  the  haunches 
depends  in  great  measure  upon  the  strength  of  the  concrete  filling, 
gravel  concrete  should  be  used  for  wide  spans. 

When  it  is  desired  to  lighten  the  construction,  voids  are  occasion- 
ally formed  in  the  concrete  of  the  haunch-filling,  by  inserting  cores 
of  stiff  pasteboard  or  of  other  composition. 

432.  b.  2.  FLAT  TILE  FLOOR  ARCHES.  SIDE-CON- 
STRUCTION. Classification  and  General  Description. — Originally, 
in  the  early  development  of  tile  systems  of  fire-proof  arches,  ther^ 
were  recognized  three  general  schemes  of  flat  tile  construction.  The 
first  and  oldest  is  known  as  the  "side-construction,"  in  which  the 
tiles  lie  side  by  side  between  the  beams,  as  shown  in  Figs.  318^ 
319,  320  and  322.  In  the  second  scheme,  known  as  the  *'end- 
construction,"  the  blocks  run  at  right-angles  to  the  beams,  abutting 
end  to  end,  as  shown  in  Fig.  323.  The  third  method,  the  "com- 
bination side-and-end-construction,"  is  a  cross  between  the  first  and 
second,  the  skew-backs,  and  sometimes  the  "keys,"  being  made  as 
in  the  side-construction,  and  the  "interiors"  abutting  end  to  end 
between  them,  as  shown  in  Figs.  333  and  334.  This  method  was 
known  by  different  names,  such  as  the  "Johnson  Arch,"  the 
"Excelsior  Arch,"  the  "Combination  Arch,"  etc. 

At  the  present  time  the  usual  classification  includes  but  two  sub- 
divisions, the  "side-construction"  and  the  "end-construction,"  as, the 
latter  is  now  usually  put  in  place  with'  side-construction  skew-backs 
and  with  either  end-construction  or  side-construction  keys. 

Early  Forms  and  Later  Improvements. — The  hollow  tile  floor 
arches  first  used  in  this  country  were  made  of  dense  tile,  formed 
essentially  like  those  shown  in  Fig.  318,  except  that  no  provision 
was  made  for  protecting  the  bottoms  of  the  beams  other  than  the 
plastering  of  the  ceiling.  It  was  soon  found  that  the  bottoms  of  the 
beams  must  be  more  thoroughly  protected  from  heat,  as  they  warped 


* 


478 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


and  twisted  so  badly  during  a  fire  that  the  destruction  of  the  build- 
ing was  threatened.  The  skew-backs  were,  therefore,  made  so  as 
to  drop  from  ^  to  i  inch  below  the  bottoms  of  the  beams,  and  so 


Fig.  318.     Early  Example  of  Side-Construction  Floor  Arch. 

as  to  eithe^*^  extend  under  the  beams  or  hold  thin  tiles  dovetailed 
between  them,  as  shown  in  the  figure.  Arches  of  this  type  were 
used  for  several  years,  but  it  was  found  that  they  were  not  strong 
enough  to  sustain  heavy  loads  and  sudden  stresses,  such  as  those 
caused  by  the  moving  of  heavy  safes,  nor  to  withstand  the  rough 


Fig.  319.    Flat  Tile  Floor  Arch.  Side-construction. 

treatment  and  heavy  weights  that  floors  are  subjected  to  while  build- 
ings are  in  course  of  erection.  The  blocks  were,  therefore,  strength- 
ened by  the  introduction  of  horizontal  and  vertical  webs,  resulting 
in  the  shapes  shown  in  Figs.  319  and  320,  which  represent  types  of 
arches  with  ribs  parallel  to  beams.    Flat  arches  are  made  up  of 


Fig.  320.    Flat  Tile  Floor  Arch.    Ribbed  Side-construction. 

various-shaped  blocks,  as  shown  in  the  drawings  and  photographs. 
Figs.  321  and  322  show  typical  block  shapes  and  different  methods 
of  assembling  various  members  of  an  arch.  Skew-backs  may  be 
either  ''plain,"  without  protection  for  the  under  sides  of  the  beams ; 


FIRE-PROOF  CONSTRUCTION— FLOORS. 


*'lipped,"  having  a  projection  molded  on  the  blocks;  or  ''sof¥it- 
skews,''  in  which  the  protection  is  a  loose  slab  held  in  place  by 
the  bevel  on  the  blocks.  The  intermediate  blocks  are  called 
*'lengtheners,"  and  the  middle  one  the  "key." 

Arches  similar  to  these  are  now  generally  made  of  semi-porous 
tiling.  The  end-construction  is  rapidly  displacing  this  side-con- 
struction, on  account  of  the  former's  greater  strength  for  the  same 
weight  of  material. 

Joints. — Most  of  the  side-construction  arches  have  bevelled  joints, 
which  are  parallel  to  the  sides  of  the  keys,  as  shown  in  Fig.  319, 
although  arches  have  sometimes  been  specified  and  made  with  radial 
joints,  as  shown  in  Fig.  320. 

Theoretically  the  radial  joint  should  make  a  stronger  arch;  but 
the  increased  cost  of  making  so  many  different  shapes  of  blocks 
and  the  endless  confusion  and  delay  in  setting  prevent  it  from 
being  much  used. 

The  blocks  in  the  side-construction  arches  break  joint  endwise,, 
thus  completely  bonding  the  arches,  as  shown  in  Fig.  319;  and  the 
failure  of  any  single  block  does  not  impair  the  strength  of  an  arch 
beyond  that  block.  In  that  respect  the  side-construction  is  superior 
to  the  end-construction. 

Depth. — A  general  rule  is  that  flat  floor  arches  should  be  of  the 
same  depth  as  the  floor  beams  supporting  them.  For  the  same  depth, 
of  beams  a  lighter  and  cheaper  floor,  as  well  as  a  stronger  one, 
is  obtained  by  using  deep  rather  than  shallow  blocks,  a  12-inch 
arch,  for  example,  weighing  less  per  square  foot,  and  also  costing 
less,  than  a  lo-inch  arch  covered  with  2  inches  of  concrete. 

In  practice  the  custom  is  to  proportion  the  depth  of  an  arch  ta 
the  span  between  the  beams  and  to  the  load.  A  safe  general  rule  is 
to  make  the  depth  of  the  blocks  1%  inches  for  each  foot  of  span, 
adding  the  thickness  of  the  protection  below  the  beams.  Some 
building  laws  require  a  greater  depth  than  this  rule  gives. 

Webs. — The  webs  are  arranged  in  various  combinations,  as  shown 
in  the  illustrations,  and  should  be  not  less  than  S/g  of  an  inch  thick. 
There  should  always  be  a  strong  web-piece  in  the  skew-back  near  the 
bottom  and  at  the  lower  flange  of  the  beam  and  in  the  line  of 
greatest  pressure.  To  reduce  the  weight  this  web  is  sometimes 
omitted ;  but  this  should  never  be  allowed,  as  floor  arches  have 
collapsed  from  this  omission  alone. 


48o 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


Safe  Loads  and  Weights. — For  safe  loads  for  different  spans,  and 
for  weights  of  arches  of  the  side-construction,  the  reader  is  referred 
to  the  complete  tables  of  the  manufacturers'  handbooks;  and  to 
condensed  tables  of  the  same  in  Kidder's  ''Architect's  and  Builder's 
Pocket-Book." 


Skews  for  Soffit 
Slab 


Plain 
Skew 


Lengtheners 


Raisd 
SkeA- 


Skews  with  Protection  Lip 


Key 


Fig.   321.    Typical  Tile  Floor  Blocks. 


Keys 


433.  b.  3.  FLAT  TILE  FLOOR  ARCHES.  END-CON- 
STRUCTION. General  Description. — In  this  method  the  blocks 
are  generally  made  approximately  rectangular  in  shape,  with  vertical 
and  horizontal  partitions,  and  with  bevelled  end-joints.  Figs.  323  to 
332  show  typical  sections  and  views  of  blocks  and  different  forms 
of  arches  of  the  end-construction.  The  pressure  on  the  blocks  is 
endwise  of  the  tiles  ;  as  the  sides  and  voids  run  at  right-angles  to  the 
I-beams.  End-construction  is  taking  the  place  of  side-construction, 
as  it  is  stronger  for  the  same  amount  of  materials. 


Fig.  322.    Tile  Floor  Arch — Typical  Side-construction  Section. 

Early  Forms  and  Later  Developments. — One  common  type  of  end- 
construction  arch  is  that  shown  in  Fig.  323,  which  was  first  brought 
into  general  use  by  Mr,  Thomas  A.  Lee,  and  which  has  been  often 
designated  as  the  '*Lee  End-method  Arch."  It  has  the  advantage  of 
simplicity  and  economy  in  manufacture,  as  all  the  blocks  for  a  given 
depth  of  arch  can  be  made  with  one  die.  Manufacturers  making 
this  type  of  arch  use  porous  and  semi-porous  terra-cotta  in  its  con- 


FIRE-PROOF  CONSTRUCTION— FLOORS.  481 


struction.  Fig.  325  shows  an  isometric  view  of  one  of  the  skew- 
backs. 

Figs.  326,  327  and  328  represent  variations  of  a  type  of  floor  arch, 
invented  and  patented  by  Mr.  E.  V.  Johnson,  formerly  of  the 
Pioneer  Company,  of  Chicago.    Fig.  326  shows  the  original  shape. 


Fig.  3-3'     End-construction  Tile  Floor  Arch.  Fig.     325.  End-construction, 

Abutment  Piece  or  Skew. 


In  order  to  obtain  a  stronger,  although  slightly  heavier,  arch  the 
shapes  were  changed  to  those  shown  in  Figs.  327  and  328,  by  Henry 
Maurer  &  Son,  of  New  York,  who,  with  the  Pioneer  Company  and 
the  Haydonville  Company  of  Ohio,  bought  the  right  to  make  and 
sell  this  arch.  The  Pioneer  Company  originally  used  a  side-con- 
struction skew-back,  as  in  Figs.  327  and  328,  but  changed  to  the  end- 
construction  form,  as  in  Fig.  326.  Messrs.  Maurer  &  Son  use  the 
side-construction  skew-back. 

Semi-porous  material  is  used  for  these  forms  of  floor  arches. 
They  are  considered  good  types  and  have  been  largely  used.  The 


Fig.  324.    End-construction  with  Side  Skews. 


shape  of  the  blocks  leaves  ample  space  for  the  tie-rods,  thus  avoiding 
cutting.  The  arches  may  be  used  in  spans  up  to  10  feet,  and  the 
depth  has  been  made  as  great  as '  20  inches,  with  a  weight  of  56 
pounds  per  square  foot. 

The  arch  shown  in  Fig.  328  is  called  the  ''Excelsior"  arch,  and  its 


482 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


limits  of  span,  weights  per  square  foot  and  the  safe  loads  allowed 
on  it  are  given  in  Kidder's  ''Architect's  and  Builder's  Pocket-Book." 

Objections  to  End-construction. — One  objection  against  this  is 
that  it  is  difficult  to  properly  bed  the  edges  of  the  blocks,  and  that 


P'"ig.  326.    End-construction,  I-beam  Shape.    End-construction  Skew. 


there  is  great  waste  of  mortar.  Complaints  have  been  occasionally 
made  by  architects  that  they  find  it  difficult  to  get  a  strictly  flat 
ceiling  with  this  type  of  arch.  The  open  ends  of  the  hollow  tiles  not 
being  well  adapted  to  receive  mortar  for  the  mortar  joints,  the 
mortar  often  squeezes  out,  permitting  some  of  the  blocks  to  drop 
below  the  others. 


Advantages. — The  principal  recommendation  for  the  end-con- 
struction is  that  if  the  arches  are  properly  set,  they  will  develop 
about  50  per   cent    more   strength   for   the   same   weight  than 


Fig.  327.    End-construction,  I-beam  Shape.    Side-construction  Skew. 


results  from  the  side-construction.  This  has  been  demonstrated  by 
theory  and  verified  by  tests.  The  advantages  of  reduced  weight 
with  equal  strength,  and  the  generally  smaller  amount  of  cutting 
for  tie-rods,  have  already  been  referred  to. 

Materials  Used. — The  materials  generally  used  for  this  type  of 


FIRE-PROOF  CONSTRUCTION— FLOORS,  483 


Fig.  329.-    End-construction  Detail.    Skew-back  and  Beam  Flange  Covering. 


484 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


construction  are  porous  and  semi-porous  tile.  The  companies  manu- 
facturing  the  patented  types  Hke  the  "Excelsior"  arch,  shown  in 
Fig.  328,  use  semi-porous  tile  for  these  forms. 

Shapes  and  Sizes  of  Intermediate  Blocks. — The  shape  of  the 
blocks  in  the  ordinary  end-construction  is  approximately  rectangular, 
with  depths  ranging  from  6  to  15  inches,  and  lengths  and  widths 
usually  12  inches,  although  they  may  be  varied. 

Webs  and  Voids. — The  thickness  of  webs  in  semi-porous  tile,  end- 
construction,  should  be  not  less  than  of  an  inch,  and  in  porous 
tile  not  less  than  ^  of  an  inch.  Increased  thickness  of  web  increases 
the  fire-resistance  as  well  as  the  strength. 

In  regard  to  the  number  of  webs  or  partitions,  it  may  be  said  that 
it  varies  with  the  size  of  the  block  and  the  weights  to  be  sustained. 
For  blocks  6  inches,  7  inches  and  8  inches  deep,  one  horizontal  web 
and  two  vertical  webs  are  used.  A  block  only  8  inches  wide  would 
have  one  horizontal  and  one  vertical  web.  Ten-inch  and  12-inch 
arch  blocks  are  made  with  one  or  two  horizontal  webs ;  and  blocks 
deeper  than  12  inches,  with  not  less  than  two  horizontal  webs.  Voids 
are  made  about  3  inches  square  in  blocks  required  for  the  greatest 
strength. 

Joints. — The  arch  blocks  must  be  set  end  to  end  in  straight  courses 
from  beam  to  beam,  and  cannot  be  set  breaking  joint  as  in  the  side- 
construction  method.  As  there  is  no  bond  between  the  rows  of  tiles, 
if  a  single  tile  in  a  row  is  broken  or  knocked  out  of  place,  the 
entire  row  is  likely  to  fall ;  and  for  the  same  reason  a  single  tile 
cannot  be  omitted  in  order  to  make  a  temporary  hole,  as  it  can 
be  in  side-construction  arches.  As  shown  in  the  figures,  the  end 
joints  are  always  bevelled,  with  the  ends  of  the  blocks  parallel. 
This  allows  all  intermediate  blocks,  or  lengtheners,  to  be  made  with 
the  same  die. 

Keys. — The  length  of  key  required  is  the  principal  deciding  factor 
in  the  choice  of  the  type  of  keys  for  end-construction  arches.  Both 
end-construction  and  side-construction  keys  are  used.  When,  with 
standard  lengtheners,  a  key  is  needed  6  inches  or  more  in  length, 
end-construction  keys  are  generally  put  in  ;  while  for  shorter  key- 
spaces,  side-construction  keys  are  generally  but  not  always  used.  A 
J^-inch  fire-clay  slab  is  frequently  inserted  between  the  ends  of  the 
*  tiles,  with'  the  end-construction  keys.    In  the  case  of  either  type 


FIRE-PROOF  CONSTRUCTION— FLOORS.  485 


of  key  the  horizontal  webs  should  be  in  line  with  those  of  the 
lengtheners. 

Skczv-backs. — Skew-backs  may  be  "flat,"  as  shown  in  Figs.  323, 
324,  325,  326,  329,  etc.,  or  "raised,"  as  shown  in  Figs.  330,  332,  etc., 
and  they  may  be  the  end-construction  or  the  side-construction,  as 
illustrated  in  the  different  figures.  Figs.  323,  325,  326  and  329  show 
end-construction  skews,  with  simple  notches  cut  in  the  ends  for  the 
bottom  flanges  of  the  beams.  Figs.  324,  327  and  328  show  side- 
construction  flat  skews. 

Although  end-construction  skew-backs  are  stronger  than  those  of 
side-construction,  the  latter  are  generally  considered  better  for  prac- 
tical use ;  and  when  they  are  made  with  the  horizontal  webs  amply 
strong  and  running  in  the  general  direction  of  the  thrust-lines  of  the 
arch,  they  develop  the  necessary  strength.  The  reasons  the  end- 
construction  skews  are  not  so  practical  and  convenient  to  use  are 
that  much  mortar  is  lost  in  the  voids,  an  even  bearing  is  secured 
with  difficulty  and  the  protection  against  fire  for  the  beams  or 
girders  is  not  as  good  as  in  the  case  of  the  side-construction  skews. 

In  case  very  deep  beams  are  used,  such  as  18-,  20-  and  24-inch 
beams,  either  a  considerable  space  must  be  filled  in  above  floor 
arches,  or  raised  skew-backs  must  be  used.  The  latter  method  is 
generally  preferable,  and  it  is  a  method  that  is  employed  for  roof 
arches  also,  where  the  arch  tops  are  usually  level  with  the  tops  of 
the  roof  beams,  and  the  light  roof  weights  require  arches  of  smaller 
depth  than  that  of  the  beams.  Figs.  330,  331  and  332  show  types  of 
side-construction  raised  skew-backs  for  end-construction  arches. 
Raised  skews  are  generally  made  in  this  way.  Fig.  331  shows  some 
variations  in  details  of  construction. 

The  use  of  raised  skew-backs  prevents  the  formation  of  flat  ceil- 
ings, unless  a  special  and  expensive  construction  is  added.  Panelled 
ceilings  result,  the  encased  beams  or  girders  appearing  below  the 
ceiling  surface ;  and  entirely  aside  from  questions  of  design,  they 
are  not  as  desirable  as  flat  ceilings,  as  they  do  not  reflect  the  light 
as  well,  and  as  they  increase  the  area  exposed  to  f>re  and  form 
pockets  for  heat  and  flame. 

Spans,  Depths,  Weights  and  Safe  Loads. — For  complete  data 
regarding  these,  the  reader  is  referred  to  the  manufacturers'  hand- 
book and  to  Kidder's  "Architect's  and  Builder's  Pocket-Book.'* 
About  5  feet  or  6  feet  are  the  commonest  arch  spans,  and  lo-inch 


BUILDING  CONSTRUCTION. 


(Ch. 


Fig.  330.    End-construction,  Raised  Side-construction  Skew-back. 


^  -ll!L  J, 

•t^ig.  331-     Details  of  Raised  Arches,   Skews  and  Flange  Covering. 


a 

" — 1^ 

D 

a' 

f — ^«g3 

ji 

Fig.  332.    End-construction,  with  Side  Raised  Skew-back  Beam  Covering. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  487 


blocks  with  lo-inch  I-beams  the  combinations  most  frequently  used. 
It  is  better,  and  about  as  cheap,  to  have  the  depth  of  arch  and  beam 
the  same. 

On  account  of  differences  in  materials  and  thicknesses  of  webs, 
manufacturers  do  not  agree  regarding  weights  of  similar  floor 
blocks. 

Tables  of  strength  cannot  be  made  which  will  apply  to  all  flat 


Fig.  333     Combination  Side-and-end-construction  Arch. 

arches  of  hollow  tile,  as  safe  loads  depend  upon  span,  depth,  sec- 
tional area  per  lineal  foot  of  arch,  and  ultimate  strength  of  the 
material  used;  and  the  last  two  conditions  vary  with  the  products 
of  different  manufacturers. 

434.  b.  4.  FLAT  TILE  FLOOR  ARCHES.  COMBINATION 
SIDE-AND-END  CONSTRUCTION.— There  are  several  styles  of 
combination  arches  now  manufactured.  The  object  of  making  this 
shape  of  arch,  as  has  already  been  mentioned,  is  to  obtain  the 
strength  of  the  end-construction  and  at  the  same  time  get  a  flat 
bearing  for  the  skew-backs.  Figs.  333  and  334  show  floor  arches  of 
combination  side-and-end-construction. 

435.  b.  5.  FLAT  FLOOR-BLOCK  OR  LINTEL  CON- 
STRUCTION.— Attempts  have  been  made  at  different  times  to 


Fig-  334-    Combination  Side-and-end-construction  Arch. 


construct  floors  of  single  terra-cotta  blocks  or  lintels  without  rein- 
forcement, spanning  from  one  beam  to  another  in  single  pieces 
and  covered  with  concrete.  The  low  maximum  limit  of  tile  span, 
however,  and  the  resulting  large  number  of  steel  beams  required, 
make  the  cost  of  such  systems  too  high  to  be  considered. 

The  Fawcett  ventilated  fire-proof  floor,  at  one  time  used  quite 


488 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


extensively,  but  now  discontinued  in  the  United  States,  was  con- 
structed on  this  principle. 

The  National  Fire-proofing  Company  for  some  years  made  a  floor 
tile  which  was  intended  to  be  used  to  span  from  beam  to  beam  when 
the  spacing  between  the  beams  did  not  exceed  3  feet ;  but  the 
manufacture  of  these  tiles  has  been  discontinued. 

Fig,  335  shows  a  type  of  arch  introduced  by  Henry  Maurer  & 
Son,  called  the  "Eureka"  arch,  and  consisting  only  of  two  skew-backs 
and  one  center  or  ''key-tile"  set  between  them.  They  are  still  made 
(1908)  for  use  in  light  work,  and  the  manufacturers  claim  they  may 
be  used  to  advantage  in  dwellings  and  apartment-houses  where  the 
loads  to  be  supported  are  almost  nominal  and  the  spans  do  not 
usually  exceed  16  feet.  Under  such  conditions  this  floor  arch  can 
be  quickly  and  cheaply  erected,  as  no  centering  is  required  and  no 
concrete  filling  except  a  little  light  filling  between  the  nailing-strips. 
But  this  construction  requires  a  uniform  spacing  of  30  inches  be- 
tween centers  of  I-beams,  and  cannot  be  used  to  advantage  with 


Fig'  335-    Eureka  Three-block  Floor  Arch. 


beams  deeper  than  6  inches.  The  entire  floor  construction  will  weigh 
about  44  pounds  per  square  foot  when  6-inch  steel  beams  and 
single  %-inch  flooring  are  used. 

436.  b.  6.  FLAT  TILE  FLOOR  CONSTRUCTION,  REIN- 
FORCED.— General  Description.  The  principle  of  reinforcement 
of  one  material  with  another,  now  so  generally  in  use  in  reinforced 
concrete  construction,  has  been  applied  to  terra-cotta  or  tile  fire- 
proof floor  construction  in  an  attempt  to  reduce,  for  the  shorter 
spans,  the  arch-block  depths,  or  to  adapt  the  flat  arch  to  wide  spans. 

The  advantage  of  this  system  is  a  greater  strength  for  the  same 
weight  per  square  foot  than  with  reinforced  concrete  construction^ 
due  to  the  disposition  of  the  material  around  voids,  and  to  the 
greater  depth.  The  disadvantage  is  a  greater  expense  than  for 
cinder  concrete,  due  both  to  the  actual  cost  of  the  materials  used  in 
the  floors  and  to  the  fact  that  there  is  more  building  as  a  whole 
because  of  the  increased  total  height  caused  by  thicker  floors. 


FIRE-PROOF   CONSTRUCTION— FLOORS. 


489 


Different  Types.  There  are  several  different  types  of  reinforced 
flat  tile  floor  construction,  and  three  of  them  will  be  briefly  men- 
tioned and  illustrated, 

1.  The  "New  York''  Reinforced  Terra-cotta  Flat  Floor  Arch 
(Bevier  patent). 

2.  The  "Johnson"  Long  Span  Reinforced  Terra-cotta  Flat  Floor 
Arch. 

3.  The  "Herculean"  Reinforced  Terra-cotta  Flat  Floor  Arch. 

I.  The  ''New  Yorf  Floor  Arch.  Figs.  336  to  340  show  details 
of  construction,  shape  of  blocks,  reinforcement,  etc.  The  arch  was 
designed  by  Mr.  P.  H.  Bevier,  of  the  New  York  branch  of  the 
National  Fire-proofing  Co.  The  following  briefly  but  sufficiently 
explains  the  construction,  and  is  condensed  and  quoted  by  permission 
from  this  company's  explanation  of  it. 

"This  arch  was  designed  for  use  where  a  light  and  cheap  but 
strong  floor  construction  with  a  flat  ceiling  is  required,  and  is  par- 
ticularly adapted  to  wide  spans  in  shallow  beams.  Where  light 
floor  construction  with  deep  beams  is  necessary  it  can  be  secured 
by  setting  the  'blocks  level  with  the  top  of  the  beams  and  using  a 
flat  metal  lath  ceiling,  or  by  omitting  the  ceiling  a  panelled  effect 
is  obtained. 

"Where  shallow  beams  are  used  the  blocks  are  set  level  and  one 
inch  below  the  bottom  of  the  beams.  Light  cinder  concrete  or  dry 
cinders  is  used  to  level  up  to  the  top  of  the  beams. 

"The  wire  truss  reinforcement  [Fig.  339]  used  in  this  system  is 
shipped  to  the  building  in  reels,  and  is  cut  to  proper  lengths  on  the 
job  as  required.  It  is  imbedded  in  Portland  cement  mortar, 
between  the  blocks,  where  it  is  protected  from  the  heat  in  case  of 
fire.  The  open-work  construction  of  the  wire  truss  enables  the 
mortar  to  flow  freely  all  about  it  and  the  joint  can  be  thoroughly 
filled  between  the  blocks  and  the  wire  perfectly  imbedded. 

"The  6-inch  arch  for  6-foot  span  and  8-inch  arch  for  7-foot  6-inch 
span  have  been  tested  by  the  Bureau  of  Buildings  of  New  York  and 
accepted  for  a  live  load  of  150  pounds  per  square  foot. 

"The  'New  York  Arch'  has  been  successfully  used  in  a  number  of 
large  buildings  in  New  York." 

Load  tests  were  made  to  determine  the  ultimate  strength  of  the 
6-inch  arch  on  a  6-feet  span,  and  it  was  found  to  be  1,600  pounds 
per  square  foot. 


490 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


Fig.  336  shows  a  perspective  of  a  typical  ''New  York"  arch,  with 
reinforcement,  the  "soffit  skew"  showing  on  the  left  and  the  "plain 
skew"  on  the  right. 

Fig.  337  shows  two  sections  of  raised  "New  York"  arches  in 
deep  beams,  one  figure  showing  a  panelled  ceiling  and  one  show- 
ing a  metal  lath  and  plaster  ceiling.  A  photograph  of  a  "beam- 
block"  for  this  construction  is  also  shown. 

Fig.  338  shows  sections  through  an  arch  parallel  to  the  beams, 
one  through  a  6-inch  arch  and  one  through  an  8-inch  arch. 

Fig.  339  shows  the  wire  truss  reinforcement. 

Fig.  340  shows  a  section  through  a  wide  span  arch,  employing 
more  than  one  wire  truss  to  give  greater  tensile  strength  at  the 
bottom  of  the  middle  part  of  the  arch.  The  ends  of  some  mcxubers 
are  turned  up  to  strengthen  the  end  blocks  and  to  prevent  failure 
by  shearing.  The  depth  of  blocks,  number  of  trusses  and  size  of 
wires  are  proportioned  to  the  load  and  span. 

For  total  weights  of  typical  floors,  see  the  full  data  with  descrip- 
tive illustrations  in  the  manufacturers'  catalogues  and  hand-books. 

2.  The  ''Johnson"  Floor  Arch.  Figs.  341,  342  and  343  show 
the  general  method  of  construction  of  this  system.  It  was  invented 
by  Mr.  E.  V.  Johnson,  and  is  now  controlled  by  the  National  Fire- 
proofing  Company.  Among  the  buildings  using  it  may  be  men- 
tioned the  post-office  building  in  Chicago.  The  basis  of  this  flooring 
consists  of  large  steel  wires  transversely  interwoven  with  still  larger 
wires  spaced,  on  an  average,  4  inches  apart.  These  latter  run 
straight  from  bearing  to  bearing.  A  woven  metal  fabric  also  is 
often  used.  Over  and  through  the  wires  or  metal  fabric  is  placed 
rich  Portland  cement  mortar  which  supports  and  unites  the  tiles, 
tending  to  make  a  monolithic  construction.  A  temporary  flat 
centering  has  to  be  first  erected  in  making  these  floors. 

This  system  does  away  with  the  necessity  for  steel  beams,  sav- 
ing weight  and  expense,  and  making  a  floor  that  stretches  from 
girder  to  girder  or  from  wall  to  wall.  It  may  be  used  with  spans 
up  to  25  feet,  16  feet  being  the  most  advantageous  span. 

The  tiles  vary  from  3  to  12  inches  in  depth,  and  are  laid  in  mor- 
tar in  continuous  rows,  breaking  joint  as  shown  in  Fig.  341,  and 
having  the  ends  square  to  the  beds.  Usually  a  2-inch  layer  of  con- 
crete is  spread  over  the  tops  of  the  tiles. 

The  fire-resisting  qualities  of  this  type  of  floor  construction  may 


FIRE-PROOF  CONSTRUCTION— FLOORS. 


Fig.  340.    New  York  Wide  Span  Double  Trussed  Arch. 


492 


BUILDING  GONSTRUCTION.         (Ch.  IX) 


be  said  to  depend  upon  the  concrete  rather  than  upon  the  tiles ;  but 
the  resuhs  of  tests  show  a  perfect  adhesion  of  the  mortar  and  a 
powerful  resistance  to  high  temperatures  without  injury. 

The  strength  of  the  construction  depends  upon  the  reinforcement 
and  the  adhesion  of  tile,  steel  and  cement  mortar.  Details  of  dif- 
ferent weights  per  square  foot,  both  with  and  without  the  cement 
on  the  top  of  the  tiles,  and  for  varying  depths  of  tiles,  are  given 
in  the  hand-books,  where  there  may  also  be  found  tables  of  the 
ultimate  strength  of  the  floors  for  different  spans  and  for  different 


"    Fig.  341.    Johnson  vSystem  of  Floor  Construction. 


thicknesses  of  tiles,  with  the  proper  factors  of  safety  to  be  used  for 
various  kinds  of  buildings. 

As  an  indication  of  the  strength  and  stiffness  of  floors  of  this 
type,  the  result  of  the  following  test  is  given:  A  uniformly  dis- 
tributed load  of  187,680  lbs.,  or  733  lbs.  per  square  foot,  was 
placed  on  a  portion  of  this  flooring,  16  feet  square,  supported  by 
walls  on  the  four  sides.    The  deflection  of  the  floor  under  this  load 


FIRE-PROOF  CONSTRUCTION— FLOORS.  493 


was  slightly  over  ^  of  an  inch,  and  with  the  load  reduced  to  one 
half  the  above,  the  deflection  was  slightly  less  than  ^  of  an  inch. 

Fig.  341  shows  a  perspective  view  of  the  general  construction, 
with  the  metal  fabric.  The  rods  are  put  in  place  as  the  fabric 
is  used.    Fig.  342  shows  an  end  view,  and  Fig.  343  a  side  view,  in 


•.•■v.>'.-:  ;V  -  -  ^  '■ 

'  //// 

N 

1 

Fig.   342.    Johnson   Floor  Arch.     End  View. 


section,  of  this  construction,  including  fabric,  rods  and  concrete 
covering  on  top  of  the  tiles. 

3.  The  "Herculean"  Floor  Arch.  Figs.  344,  345,  346  and  347 
show  the  general  construction  of  this  form  of  floor  arch.  It  was 
patented  by  Henry  Maurer  &  Son,  in  1898  and  1900,  and  is  manu- 
factured by  them. 

This  form  of  arch  is  well  adapted  to  large  spans,  up  to  22  feet^ 
eliminating  entirely  the  use  of  steel  beams.  The  miaterial  used  is 
semi-porous  terra-cotta.  The  only  metal  employed  is  T-iron,  thor- 
oughly imbedded  in  Portland  cement  mortar  to  prevent  corrosion  : 
and  as  a  further  protection  the  metal  is  covered  by  not  less  than  2 
inches  of  terra-cotta. 

An  arch  measuring  18  feet  from  wall  to  wall,  loaded  with 




=1 

r? 

1  1 
1  1 
1  1 
1  1 

1 

-1 

Fig.   343.    Johnson   Floor  Arch.     Side  View. 


108,000  pounds  of  hard  bricks  distributed  over  a  surface  of  180 
square  feet  (600  pounds  to  the  square  foot),  and  left  standing  for 
three  weeks,  showed  no  perceptible  deflection. 

The  blocks  are  12  inches  by  12  inches  on  top  and  vary  in  depth 
from  8  to  12  inches,  as  required.    There  are. grooves  in  the  sides  of 


494 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


the  blocks  to  accommodate  the  T-bars,  which  are  lyi  by  by  1% 
inches  in  their  dimensions,  and  which  extend  the  full  length  of  the 
span.  The  blocks  break  joint  in  plan,  are  filled  with  cement  mortar 
and  have  a  bearing  of  from  4  to  6  inches  on  the  walls  or  girders. 

The  system  possesses  good  fire-proofing  qualities,  the  steel  ten- 
sion members  being  well  protected  against  fire  by  an  ample  thick- 
ness of  terra-cotta. 

Some  of  the  advantages  claimed  for  this  construction  are  its  low 
cost  compared  with  floors  of  equal  fire-resisting  qualities,  and  of  a 
design  requiring  steel  beams  every  6  or  8  feet ;  its  ready  adaptation 
to  buildings  with  masonry  walls  and  partitions  and  with  little  struc- 


Fig.  344,     Herculean  Floor  Arch. 


tural  steel ;  its  unusually  smooth  undersurface  or  ceiling,  resulting 
in  a  reduced  cost  of  plastering ;  and  its  erection  without  tie-rods. 

Fig.  344  shows  in  perspective  a  portion  of  this  arch,  showing  a 
late  improved  form  of  blocks,  with  the  reinforcing  T-bars  in  place. 

Fig.  345  shows  a  lo-inch  arch,  of  span  over  20  feet,  resting  on 
an  outer  wall  and  on  a  2-feet  plate-girder,  the  sides  and  lower 
flanges  of  which  are  fire-proofed  with  hollow  tile  blocks.  Owing 
to  the  extended  span,  over  20  feet,  and  the  elimination  of  beams, 
heavier  girders  become  necessary  to  sustain  the  loads.  By  using 
"shoe-tiles"  and  blocks  as  shown,  the  arch  is  raised  nearly  to  the 
floor  level  and  needs  but  little  concrete  filling. 

Fig.  346  shows  arches  resting  on  two  18-inch  girders,  and  arches 


FIRE-PROOF  CONSTRUCTION— FLOORS.  495 

resting  on  one  18-inch  girder,  the  girders  being  fire-proofed  as 
shown. 

Fig.  347  shows  an  arch  resting  on  I-beams,  for  use  in  dwelhngs 
and  other  structures  in  which  a  flat  ceiHng  is  w«<:!ted.  The  blocks 
adjoining  the  I-beams  are  cut  to  drop  below  them  so  as  to  receive 
the  soffit  tiles  and  thereby  fire-proof  the  bottom  flanges.    As  the 


I 

f'l      1      1     //     1  1 

1 

□0 

□□ 

=^ — ^ — I'i    1  1 — 

A 

□  □ 

0  e>  0 

li 

■t'^ig-  345.     Herculean  Floor  Arch  and  Girder  Covering. 


1 

1     1     1   / 1     1  1 

I  1 

N  1 

0 

Fig. 

347.  Herculean 

Floor 

Arch  and  Beam  Covering 

arch  comes  nearly  to  the  tops  of  the  beams,  it  is  only  necessary  to 
put  on  sufficient  concrete  to  imbed  the  floor  sleepers. 

437-  7.  THE  GUASTAVINO  TILE  ARCH,  VAULT 
AND  DOME  CONSTRUCTION.— 

General  Construction. — This  is  a  method  of  constructing  lights 
strong,  fire-proof  masonry,  domes,  vaulted  ceilings,  floors,  etc.,  by 


496 


BUILDING  CONSTRUCTION.  (Ch.  IX) 


means  of  hard-burned,  semi-porous  terra-cotta  slabs,  i  inch  in 
thickness,  about  6  inches  in  width  and  from  12  to  24  inches  in 
length,  laid  so  as  to  break  joint  in  successive  layers  and  all  bonded 
together  in  Portland  cement  mortar  so  as  to  make  one  solid  mass. 
It  was  devised  by  the  R.  Guastavino  Company,  of  New  York  and 
Boston. 

The  floors  in  this  system  are  built  by  spanning  the  space  between 
the  girders  with  a  single  arch,  vault,  or  dome,  constituted  of  two, 
three  or  more  thicknesses  of  these  i-inch  tiles,  depending  upon  the 
dimensions  of  the  arch,  vault  or  dome.  In  its  best  application,  steel 
is  used  in  tension  only,  as  tie-members,  and,  in  place  of  steel  girders, 
tile  girders  are  constructed  of  the  latter  material.  Wherever  steel 
is  used  it  is  imbedded  in  the  masonry  construction. 

Examples. — One  of  the  earliest  notable  buildings  using  this  sys- 
tem of  construction  is  the  Boston  Public  Library,  erected  in  1892; 
and  some  of  the  later  important  constructions  following  this  are 
the  Hall  of  Fame  and  the  Library  building  of  the  University  of 
New  York  and  the  Metropolitan  Museum  of  Art,  New  York; 
the  Massachusetts  Horticultural  building,  the  American  Type 
Foundry  building,  and  the  Massachusetts  General  Hospital,  Boston ; 
and  the  Minnesota  State  Capitol  building,  St.  Paul,  Minn. 

The  floor  above  the  crypt  of  the  Cathedral  of  St.  John  the 
Divine,  in  New  York,  measuring  56  by  60  feet,  with  no  interior 
supports,  and  designed  to  carry  a  safe  load  of  400  pounds  per 
square  foot,  is  constructed  on  this  principle,  and  is  an  example  of 
wide-span  arching. 

Whenever  a  vaulted  ceiling  is  desired  this  seems  to  be  the  best 
system  of  construction  yet  devised. 

Strength. — Floors  built  on  this  principle  have  been  tested  under 
the  supervision  of  the  New  York  Building  Department  up  to  3,700 
pounds  per  square  foot,  with  spans  of  10  feet. 

When  used  between  I-beams  the  only  steel  beams  required  are 
those  spanning  from  column  to  column. 

Architects  contemplating  the  use  of  this  system  of  construction 
are  advised  to  consult  the  R.  Guastavino  Company  before  letting 
any  contracts. 

CSsf. — Wherever  vaulted  ceilings  are  required  this  construction 
is  as  cheap  or  cheaper  than  any  other  form  of  equally  fire-proof 
construction.    One  particular  advantage  of  this  system  is  the  possi- 


TILE  ARCH  DOME  CONSTRUCTION. 


497 


bility  of  making  one  course  of  tile  of  pressed  or  glazed  material, 
thus  obtaining  a  most  effective  and  permanent  finish,  as  in  the  case 
of  the  City  Hall  station  of  the  New  York  Subway,  which  is  con- 
structed for  very  heavy  loads  without  the  use  of  steel. 

Advan'Mges. — The  advantage  over  concrete  of  this  masonry 
vaulting  for  domes  is  that  it  is  self-supporting  during  construction ; 
and  the  lumber  used  consists  of  light  pieces  only,  which,  as  skeleton 
templates,  serve  principally  to  give  the  curve  required.  In  con- 
crete work,  owing  to  the  immense  weight  of  the  mass  to  be  sup- 
ported until  it  sets,  and  to  the  necessity  of  building  up  the  forms 
solidly  with  heavy  timber,  an  enormous  amount  of  timber  and 
planking  is  required ;  and  the  expansion  and  contraction  of  this 
material,  due  to  the  absorption  of  water  and  the  drying  out,  fre- 
quently cause  cracking  and  other  defects  in  the  concrete  shells. 
The  Guastavino  construction  being  self-supporting  during  erection, 
is  free  from  these  disadvantages,  and  naturally  commends  itself  for 
large  spans  where  strength,  durability,  architectural  beauty  and 
design,  combined  with  lightness  and  stability,  are  essential  features. 

Recent  Typical  Large  Domes. — The  following  are  some  typical 
large  domes  erected  with  the  Guastavino  tile  arch  construction : 

New  Custom  House,  New  York;  elliptical  dome,  major  axis,  130 
feet. 

New  Girard  Trust  Company's  building,  Philadelphia ;  hemis- 
pherical dome,  loi  feet  in  diameter. 

Rodef  Sholem  Synagogue,  Pittsburg,  Pa. ;  quadrangular  dome, 
92  feet  in  diameter. 

Library  building.  University  of  New  York ;  dome,  90  feet  in 
diameter. 

Rotunda,  University  of  Virginia ;  dome,  69  feet  in  diameter. 
Hall  of  Sciences,  Brooklyn,  N.  Y. ;  dome,  60  feet  in  diameter. 
Bank  of  Montreal,  Montreal,  Can. ;  dome,  72  feet  in  diameter. 
Grace  Universalist  Church,  Lowell,  Mass. ;  dome,  70  feet  in 
diameter. 

McKinley  Memorial,  Cleveland,  Ohio ;  dome,  58  feet  in  diameter. 
Minnesota  State  Capitol,  St.  Paul,  Minn. ;  dome,  60  feet  in 
diameter. 

On  some  of  the  above  domes,  such  as  that  of  the  Girard  Trust 
Company's  building  and  of  the  McKinley  Memorial,  a  heavy  stone 
exterior  finish,  several  inches  in  thickness,  has  been  applied  directly ; 


498 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


in  other  instances,  such  as  in  the  54-feet  diameter  dome  of  the 
Columbia  University  Chapel,  New  York,  and  in  the  52-feet  diameter 
dome  of  the  Madison  Square  Presbyterian  Church,  New  York, 
porous  tiles  are  used  for  the  exterior  constructive  course,  to  which 
the  finishing  tile  or  copper  is  attached  by  nailing. 

2.    c.    CONCRETE  FLOOR  ARCH  CONSTRUCTION. 

438.  GENERAL  CONSIDERATIONS.— Having  considered, 
in  fire-proof  floor  construction,  the  use  of  tile  or  terra-cotta, 
employed  both  alone  and  with  reinforcing  metal,  there  remains  to 
be  briefly  discussed  the  very  important  and  useful  fire-proof  floor 
construction,  employing  reinforced  concrete  for  its  materials.  The 
concrete  may  be  used  without  the  reinforcement,  but  such  construc- 
tion is  not  practicable  for  any  but  very  short  spans  because  of  its 
necessarily  great  thickness  and  weight  and  consequent  expense. 

Concrete  and  reinforced  concrete  floor  construction  will  be  con- 
sidered here,  reinforced  concrete  construction  in  general  being 
discussed  in  the  chapter  devoted  to  that  subject. 

Advantages. — The  principal  advantages  claimed  for  reinforced 
concrete  floor  construction  over  tile  construction  may  be  enumerated 
as  follows : 

1.  Great  adaptability  to  irregular  framing  and  connections. 

2.  Rapidity  of  construction. 

3.  Generally  but  not  universally  smaller  weights  per  square  foot 
of  floor. 

4.  Economy,  considering  the  total  cost  of  the  steel  frame  and  the 
•  floor  systems  themselves. 

Disadvantages. — The  principal  disadvantages  are : 

1.  More  or  less  interference  with  the  progress  of  other  parts 
of  the  work. 

2.  Frequent  long  delays  in  proceeding  with  other  interior  work 
and  finishings  after  floors  are  put  in,  caused  by  slowness  in  drying 
out. 

3.  Delays  in  installation  on  account  of  cold  weather. 

4.  Greater  chances  of  poor  construction  on  account  of  inferior 
work  and  manipulation  of  materials  by  unskilled  labor. 

It  is  the  opinion  of  the  writer  that  from  what  is  known  at  the 
present  time,  it  cannot  be  said  that  either  kind  of  floor  construction 
is  very  much  better  or  worse  than  the  other.    Either  cinder  con- 


FIRE-PROOF  CONSTRUCTION— FLOORS. 


Crete  or  tile  fire-proofing  will  probably  stand  any  test  of  fire  to 
which  it  is  likely  to  be  subjected,  if  the  workmanship  and  materials 
are  of  the  very  best.  Artificial  tests  of  any  system  are  almost  invar- 
iably successful  because  the  arches  are  always  built  of  the  best 
materials  of  their  respective  kinds  and  in  the  best  possible  manner. 

In  examinations  of  the  efifects  of  great  heat  upon  different  build- 
ing materials  in  the  recent  great  conflagrations,  advocates  of  both 
kinds  of  fire-proof  floor  construction  have  often  undoubtedly  found 
what  they  looked  for. 

It  may  be  said  that  there  have  not  been  as  many  tests  in  great 
fires  of  concrete  construction  as  of  brick,  terra-cotta  and  tile,  all 
unquestionably  splendid  fire-proofing  materials ;  but  it  musi  also  be 
admitted  that  the  enormous  amount  of  concrete  construction  now 
under  way  in  all  parts  of  the  world  where  building  operations  are 
carried  on  implies  great  confidence  on  the  part  of  architects  and 
engineers  in  its  efliciency  in  many  kinds  of  structures. 

439.  THE  COMPOSITION  OF  CONCRETE.— The  materials 
used  in  making  concrete  of  various  kinds,  with  their  proportions, 
and  with  data  regarding  other  details  belonging  to  concrete  mix- 
ing, and  putting  in  place,  etc.,  are  discussed  in  Chapter  X,  on  ''Con- 
crete and  Reinforced  Concrete  Construction." 

.440.  DIFFERENT  FORMS  AND  METHODS  OF  REIN- 
FORCEMENT.— The  discussion  of  the  principal  types  of  the  many 
shapes  of  reinforcing  metals  also  is  taken  up  in  Chapter  X.  While 
many  of  these  different  types  are  used  in  concrete  floor  construc- 
tion, there  are  still  other  types  of  metal  reinforcing  used  in  floors, 
but  not  so  w^ell  adapted  to  concrete  beams  or  girders.  These  latter 
forms  will  be  briefly  mentioned  in  the  present  division  of  the  subject 
in  connection  with  the  different  types  of  reinforced  concrete  floor 
construction. 

Rods  and  Bars  versus  Wire  Fabrics. — Both  types  are  used  and 
good  results  are  obtained  from  each.  The  theory  of  reinforced 
concrete  beams  and  slabs,  however,  would  seem  to  indicate  round 
or  square  bars,  plain  or  deformed,  from  ^  to  ^  of  an  inch  in  size, 
and  properly  spaced  as  required  for  the  varying  loads  and  spans, 
as  the  ideal  reinforcement  for  fire-proof  floors.  The  number  and 
size  of  the  bars  should  be  such  that,  within  certain  limits,  the 
adhesion  between  steel  and  concrete  will  be  a  maximum. 

While  wire  fabric  reinforcements  have  certain  advantages,  they 


500 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


have  also  the  disadvantage  of  greater  liabiHty  to  corrode,  on  account 
of  the  smaller  sections.  They  also  lend  themselves  more  readily  to  a 
displacement  during  the  putting  in  place  of  the  concrete,  possibly 
moving  too  high  to  strengthen  the  floor  as  required,  or  falling  too 
low  and  becoming  exposed  to  corrosion  or  fire. 

Position  and  Direction  of  Reinforcement. — As  the  function  of 
the  reinforcing  metal  is  to  take  up  the  tensional  stresses,  it  is  placed, 
in  floor  arch  construction,  near  the  lower  surface  of  the  floor  slabs. 

The  transverse  reinforcing  bars  or  wire  strands  are  stressed 
when  the  floor  loads  are  uniformly  distributed  and  the  longitudinal 
reinforcing  bars  when  the  loads  are  concentrated.  Both  should  be 
put  in.  With  reinforcement  in  the  form  of  vertical  bars,  the  latter 
often  tend  to  shear  through  the  concrete  when  the  floors  are  heavy. 

Types  of  Reinforced  Concrete  Floor  Arch  Construction. — Three 
general  types  of  this  construction  will  be  considered: 

1.  Segmental  Concrete  Floor  Construction. 

2.  Flat  Concrete  Floor  Construction. 

3.  Sectional  Concrete  Floor  Construction. 

c     I.    SEGMENTAL  CONCRETE  FLOOR  ARCHES. 

441.  GENERAL  DESCRIPTION.— When  concrete  is  so  dis- 
posed that  it  acts  almost  entirely  in  compression,  it  is  in  the  b§st 
form  to  resist  stresses ;  and  consequently  the  arched  form  is  better 
than  the  flat  form  for  floor  construction,  especially  in  those  build- 
ings in  which  the  floor  loads  are  very  heavy,  and  in  which  a  flat 
ceiling  is  not  necessary. 

These  arched  concrete  floor  systems  are  put  in  place  with  various 
modifications  of  details,  the  reinforcing  consisting  of  rods,  bars,  tees, 
channels  and  dififerent  kinds  of  netting  and  wire  fabric,  when  wide 
spans  require  them.    Tie-rods  are  required  in  all  cases. 

The  patents  taken  out  for  several  arched  concrete  systems  are 
mainly  for  those  details  which  are  connected  w^ith  the  putting  of  the 
work  in  place,  the  use  of  which  often  leads  to  greater  convenience 
and  economy  in  installation. 

For  data  regarding  the  strength  of  concrete  floor  arches  for 
spans  over  5  feet,  both  plain  and  with  different  forms  of  reinforce- 
ment, and  also  regarding  their  strength  when  compared  with  that 
of  arches  of  other  fire-resisting  materials,  the  reader  is  referred  to 
Kidder's  "Architect's  and  Builder's  Pocket-Book,"  Chapter  XXIII, 


FIRE-PROOF  CONST  RUCTION— FLOORS. 


501 


which  contains  a  condensed  account  of  the  celebrated  ''Austrian 
Experiments"  on  these  floor  arches.  The  two  following  general 
statements  may  be  made,  how^ever,  regarding  their  strength,  when 
their  spans  are  5  feet  or  less,  and  when  there  is  no  reinforcement : 

(1)  When  made  of  gravel-concrete  of  a  i  to  6  mixture,  and 
with  a  thickness  of  3  inches  at  the  crown,  a  floor  arch  should  sus- 
tain, without  cracking,  a  uniformly  distributed  load  of  1,500 
pounds  per  square  foot. 

(2)  When  made  of  cinder-concrete,  floor  arches  are  inferior  to 
those  made  of  gravel-concrete  in  strength  only.  The  thickness  at 
the  crown  should  be  not  less  than  4  inches,  and  the  rise  at  least 
one-eighth  of  the  span.  Such  an  arch  has  approximately  the  same 
strength  as  a  segmental  tile  6-inch  arch  of  the  same  span. 

442.  THE  ROEBLING  CONCRETE  FLOOR  ARCH  SYS- 
TEM.— Figs.  348  to  351  show  the  general  construction  of  the 
various  types  of  the  concrete  arch  floor  system  of  the  Roebling 
Construction  Company.  This  system  has  been  used  in  many  build- 
ings and  is  very  strong;  and  it  is  also  eminently  fire-resisting  when 
the  type  used  includes  the  thorough  protection  of  the  bottoms  of  the 
steel  beams  as  shown  in  the  illustrations. 

In  this  system  no  wood  centers  are  required,  as  the  arched  wire 
lathing  with  its  interwoven  steel  rods  itself  forms  the  permanent 
centering;  and  as  this  wire  centering  is  made  at  the  factory  to 
readily  fit  into  place,  and  is  arched  in  advance  of  the  concrete 
v^ork,  the  latter  progresses  rapidly  and  continuously.  This  center- 
ing will  hold  a  considerable  load  itself,  and  is  looked  upon  as  a  sort 
of  safeguard  in  the  case  of  accidents,  such  as  the  falling  of  a  work- 
man. It  is  also  preferable  to  wood  centering  in  permitting  an} 
excess  of  water  to  drip  down  from  the  fresh  concrete. 

The  Roebling  Construction  Company  furnishes  tables  giving  all 
required  data  for  different  spans  and  types  of  construction,  such  as 
maximum  allowable  spacing  of  steel  beams,  total  levels  of  concrete 
at  spring  of  arch,  thickness  of  concrete  in  middle  part  of  arch, 
w^eight  per  square  foot,  safe  loads,  etc. 

The  average  safe  loads  with  a  liberal  factor  of  safety  may  be 
taken  at  from  800  to  1,000  lbs.  per  square  foot,  when  the  spans  are 
between  5  and  6  feet.  The  figures  show 'the  usual  average  maxi- 
mum spans  desirable  for  the  different  types.  The  thickness  at  the 
crown  is  usually  3  inches.    In  types  i,  2  and  3,  Figs.  348,  349  and 


502 


BUILDING  CONSTRUCTION.         (Ch.  IXy 


351,  the  clear  rise  of  the  arch  is  usually  made  inches  to  each 
foot  of  span.  For  a  14-feet  span  with  18-inch  I-beams,  the  rise 
has  been  made  about  14  inches,  and  for  an  i8-feet  span,  also  with 
18-inch  I-beams,  the  rise  has  been  made  16  inches.  The  depth  of 
the  concrete  arch  at  the  haunches  becomes  correspondingly  greater 
with  the  increased  width  of  the  spans. 

Fig.  348  shows  System  A,  Type  i,  of  the  Roebling  floor  arch 
system.  A  6-feet  span  is  the  maximum  recommended.  The  ceil- 
ing construction  and  the  method  of  fire-proofing  the  columns  and 
girders  are  also  shown.  This  type  is  recommended  by  the  manu- 
facturers for  public  buildings,  offices,  theatres,  hotels,  schools^ 
churches,  banks,  libraries,  hospitals,  residences,  etc. 

Fig.  349  shows  System  A,  Type  2,  in  which  the  maximum  spans 
desirable  are  6  feet  6  inches  or  7  feet,  and  w^hich  is  called  the 
^'Warehouse"  Construction.  It  is  adapted  also  to  factories,  stores, 
freight  depots,  breweries,  etc.  The  flat  ceiling  is  omitted,  and  the 
soffits  of  the  beams  and  girders  are  well  protected  with  concrete  in 
the  rounded  form  shown. 

Fig.  350  shows  a  variation  of  System  A,  Type  2,  with  a  recom- 
mended maximum  span  of  5  feet.  The  flat  ceiling  is  omitted  here 
also.  When  the  beams  are  spaced  not  too  far  apart,  and  when  no 
piping  is  to  be  placed  transversely  over  them,  the  floor  strips  or 
sleepers  may  be  depressed  below  the  top  flanges,  reducing  the  total 
depth  of  the  floor  by  the  depth  of  the  sleepers. 

System  A,  Type  3,  is  quite  similar  to  Type  2,  the  difiference  being 
an  added  suspended  flat  ceiling  which  may  be  fixed  below  the  beams 
at  any  distance  desired,  in  order  to  allow  for  piping,  etc. 

Fig,  351  shows  System  A,  Type  4.  It  is  used  where  the  beams 
or  supports  are  more  than  10  feet  apart,  and  has  been  installed  with 
success  in  spans  up  to  18  feet.  This  type  is  similar  to  the  others, 
except  that  curved  T-section  ribs  are  used  instead  of  the  solid  steel 
rods,  in  the  arch  wire.  The  T's  are  of  suitable  sectional  area  to 
support  the  loads,  and  are  spaced  2  feet  apart  and  held  rigidly  in 
position  by  means  of  steel  spacers.  The  wire  lath  is  then  laid 
between  the  T's  and  laced  to  them,  and  on  this  permanent  centering 
the  concrete  is  laid  in  the  usual  manner, 

443.  THE  RAPP  T-RIB,  BRICK  AND  CONCRETE  FLOOR 
ARCH  SYSTEM. — Figs.  352  and  353  show  the  general  type  of 
construction  of  this  system,  which  combines  the  strength  of  the 


FIRE-PROOF  CONSTRUCTION— FLOORS.  503 


Fig.  348.    Roebling  Arch,  System  A.    Type  i. 


Fig.  349.    Roebling  Arch,  System  A.      Type  2. 


Fig.  350.    Roebling  Arch,  System  A.    Type  2.    Sleepers  Depressed. 


Fig.  351.     Roebling  Arch,  System  A.    Type  4. 


564  BUILDING  CONSTRUCTION.         (Ch.  IX) 

ordinary  row-lock  brick  arch  with  that  of  the  steel  T-ribs.  A 
cinder  concrete  filling  in  the  form  of  an  arch  is  placed  above  the 
brick  and  T-rib  construction.  The  system  can  be  installed  with 
rapidity,  in  a  continuous  operation,  and  no  wood  centering  is 
required,  the  T's  serving  as  a  centering.    By  special  arrangement 


Fig.   352.    Kapp  System.     Type  A. 


the  Rapp  Fire-proofing  Company  uses  the  Roebling  patent  wire  lath 
ceiling  construction  whenever  flat  ceilings  are  required. 

There  are  three  types  of  this  system.  Fig.  352  shows  Type  A 
in  which  the  bricks  are  laid  flat  side  down.  The  T's  abut  against  the 
seat  formed  by  the  web  and  lower  flange  of  the  steel  floor  beams, 
and  are  held  in  place  by  steel  separators.  A  2-inch  thick  segmental 
common  brick  arch  is  then  formed  by  laying  the  bricks  flat  between 
ihe  T's  which  are  set  about  8^  inches  on  centers.    The  usual  cin- 


Fig.   353.    Rapp  System.     Type  C. 


der  concrete  filling,  in  the  form  of  a  segmental  arch,  is  then  put  in 
over  the  brick  and  T-rib  construction.  In  spans  up  to  10  feet,  the 
average  ultimate  strength  for  a  distributed  load  is  3,000  pounds  per 
square  foot. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  505 


The  flat  ceiling  construction  shown  is  the  RoebHng  standard  wire 
lath  ceiling. 

Type  B  is  similar  to  Type  A,  except  that  the  bricks  are  set  on 
edge.  The  resulting  construction  is  the  same  as  the  usual  4-inch 
row-lock  brick  arch,  with  an  additional  reinforcing  of  the  T-ribs ; 
and  it  has  approximately  double  the  strength  of  Type  A.  It  is  used 
in  spans  up  to  12  feet. 

Type  C  shows  the  Rapp  system  with  a  special  skew-back  and 
segmental  arched  flooring  without  suspended  flat  ceiling.  It  is  well 
adapted  to  factories,  warehouses,  lofts,  depots,  etc.  The  skew- 
back  is  made  solid  and  protects  the  soffit  of  the  steel  floor  beams. 
The  ceilings  may  be  plastered  directly  on  the  under  side  of  floor 
arches,  or  the  brickwork  may  be  pointed.* 

c.    2.    FLAT  CONCRETE  FLOOR  CONSTRUCTION, 
REINFORCED. 

444.  GENERAL  DESCRIPTION.— Flat  reinforced  concrete 
floor  construction  can  be  considered  under  two  general  headings  ; 
the  systems  which  are  patented  and  the  systems  which  are  based 
upon  the  same  general  principles  as  the  former,  but  which  any  one 
may  use. 

All  of  them,  patented  or  unpatented,  consist  generally  of  con- 
crete slabs  of  different  thicknesses,  set  between  or  on  the  steel  floor 
beams  and  reinforced  at  or  near  the  under  surfaces  with  various 
steel  metal,  wire,  fabric,  bars,  rods,  lath,  sheets,  plates,  etc.,  and  the 
general  principles  are  about  the  same  in'  all. 

The  character  of  the  ceilings  and  the  amount  of  fire-resisting  fill- 
ing about  the  floor  system  to  the  under  side  of  the  flooring,  depend 
upon  the  position  of  the  concrete  slabs  in  relation  to  the  top  and 
bottom  flanges  of  the  floor  beams. 

In  regard  to  the  thicknesses  of  these  slabs  in  flat  reinforced  con- 
crete floor  construction,  it  may  be  said  that  they  are  not  generally 
as  deep  as  the  floor  beams,  and  that  the  minimum  thickness  is 
usually  put  at  35^  inches.  A  general  rule  is  to  make  the  thickness 
of  the  concrete  slab  not  less  than  of  an  inch  for  each  foot  of  span. 
The  thicknesses  vary  with  the  systems  and  the  forms  of  reinforce- 
ment employed. 

Some  of  the  patented  systems  of  flat  concrete  floor  construction 
will  be  considered  first. 

*  See  Article  448a  for  White  Segmental  Floor  Arch  System. 


5o6 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


445.  THE  COLUMBIAN  FLAT  CONCRETE  FLOO%CON. 
STRUCTION,  REINFORCED.*— Figs.  354  to  361  show  the  gen- 
eral construction  of  this  system,  a  flat  concrete  system,  in  which 
the  concrete,  instead  of  being  supported  by  wires  or  netting,  is 
reinforced  by  ribbed  steel  bars  of  various  sizes  and  weights,  attached 
to  the  supporting  beams  by  stirrup  connections,  or  placed  upon 
either  flange  of  these  beams,  or  framed  into  them  with  bolted  angle 
connections. 

The  ribbed  steel  reinforcing  bars  are  made  in  sizes  of  }i,  i,  2, 


Fig.     354.    Columbian     System.  Fig.  355-    Columbian  System.     Steel  Stirrup. 

Ribbed  Bars. 


31^,  4)4  and  5  inches  in  height,  most  of  them  being  in  either 
heavy  or  light  weight,  with  section  areas  varying  from  .27  of  a 
square  inch  to  2  square  inches,  and  with  weights  per  lineal  foot  of 
from  .7  of  a  lb.  to  6.8  pounds.  The  %-inch  and  i-inch  bars  have 
one  rib,  the  5-inch  bar  has  three  ribs  and  the  others  have  two  ribs, 
as  shown  in  Fig.  354. 

At  the  required  distance  below  the  tops  of  the  floor  beams  a 
temporary  wood  centering  is  built,  and  the  bars  are  imbedded  in  and 
entirely  surrounded  by  cinder,  slag  or  stone  concrete,  of  a  thick- 
ness and  mixture  determined  by  the  spans,  loading  and  specifica- 
tions. The  beams  and  girders  also  are  incased  with  concrete  slabs, 
with  insulating  air-spaces. 


*  Patents  controlled  by  the  Columbian  Fire-proofing  Co.,  of  Pittsburg,  Pa. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  so? 

There  are  two  systems  of  Columbian  fire-proof  floor  construc- 
tion, viz.,  the  Short  Span  System  and  the  Long  Span  System,  each 
system  having  variations.    They  are  as  follows : 


COLUMBIAN  FLAT  CONCRETE  CONSTRUCTION. 


System 

Connections  Between 
Bars  and  Beams 

Standard  Relation  of  Beam  and  Slab 

Short  span  system  A 
Short  span  system  B 
Short  span  system  C 
Short  span  system  D 
Long  span  system  A 
Long  span  system  B 
Long  span  system  C 
Long  span  system  D 

Stirrups  over  beams 
Over  top  flange 
Over  bottom  flange 
Over  concrete  beams 
Stirrups  over  beams 
Angles  and  bolts 
Over  top  flange 
Over  concrete  beams 

Top  flush  with  top  of  beam 

Bottom  %  of  an  inch  below  top  of  beam 

Bottom  1  inch  below  bottom  of  beam 

Top  flush  with  top  or  bottom  of  beam 

Top  flush  with  top  of  beam 

Tc  p  flush  with  top  of  beam 

Bottom  %  of  an  inch  below  top  of  beam 

Top  flush  with  top  or  bottom  of  beam 

The  Systems  D  in  each  case  above  are  used  when  the  beam  and 
girder  construction  or  the  entire  building  is  of  reinforced  concrete. 

Either  a  panelled  ceiling  construction  or  a  flat  level  ceiling  is 
formed.  In  case  the  latter  finish  is  desired,  it  is  obtained  as  in 
System  C,  short  span,  or  constructed  independently  of  the  floors 
with  concrete  and  rods,  bars,  wire  lath  or  expanded-metal,  etc.,  con- 
nected with  the  lower  flanges  of  the  floor  beams. 

The  maximum  spacing  of  the  bars  is  24  inches.  In  the  short 
span  system  three  sizes  of  bars  are  used,  the  i,  2  and  23/^-inch  bars; 
and  in  the  long  span  systems  the  3^,  4^4  and  5-inch  bars. 

The  smaller  bars  for  the  shorter  spans  give  respectively  3,  3j^ 
and  4  inches  of  concrete ;  and  the  larger  bars  for  the  longer  spans 
give  respectively  5,  5^  and  63^  inches  of  concrete. 

The  maximum  span  for  short  span  systems  A  and  B  is  12  feet, 
for  short  span  system  C  10  feet,  for  the  long  span  systems,  20 
feet.  For  the  short  span  systems  using  i-inch  bars,  the  most  eco- 
nomical spacing  of  floor  beams  is  usually  6  feet  for  office-buildings, 
hotels  and  apartment-houses,  and  from  6  to  9  feet  for  buildings 
using  2  and  2^-inch  bars,  in  which  the  floor  loads  are  greater. 

In  the  long  span  systems  the  bars  are  either  hung  in  stirrups 
especially  made,  or  framed  by  bolted  angle  connections  to  the  beam- 
girders  ;  and  in  the  end  spans  they  are  anchored  into  the  walls.  In 
this  way  floor  beams  may  be  omitted  between  girders,  the  reinforced 
monolithic  concrete  slabs  spanning  from  girder  to  girder  or  from 
girder  to  walls. 


F.ig-  357-    Columbian  System.    Short  Span.    System  B. 


I'ig-  359-    Columbian  System.    Long  Span.    System  A. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  509 


Nailing-strips  are  imbedded  in  the  filling,  or  nailed  to  the  con- 
crete flooring  with  the  filling  omitted. 

The  carrying  capacity  for  these  floors  is  stated  in  full  in  the 
hand-books  and  catalogues,  which  give  guaranteed  safe  loads. 
Overloading  causes  a  gradual  bending,  and  not  a  sudden  failure. 
The  resistance  to  concentrated  loads  is  great,  and  the  construction 
is  especially  strong  in  resisting  drop  or  jarring  loads. 

Fig.  354  shows  sections  of  the  different  ribbed  bars. 

Fig.  355  shows  the  steel  stirrup  for  the  two-ribbed,  bars. 

Fig.  356  shows  sections  of  short  span  system  A,  suitable  for 
I -inch,  2-inch  and  2^ -inch  bar  floors,  with  stirrups  over  beams  aife 
top  of  slabs  flush  with  top  of  beams. 

Fig.  357  shows  sections  of  short  span  system  B,  suitable  for 

1-  inch,  2-inch  and  2^-inch  bar  floors.  Bars  continuous  oyer  tops 
of  beams,  and  bottom  of  slabs  ^  inch  below  tops  of  beams. 

Fig.  358  shows  short  span  system  C,  suitable  for  i-inch  and 

2-  inch  bar  floors.  Ribbed  bars  supported  on  bottom  flanges  of  floor 
beams,  and  bottom  of  slab  i  inch  below  bottoms  of  beams.  A  light 
cinder  fill  is  recommended,  put  in  to  the  tops  of  the  floor  beams. 

Fig.  359  shows  long  span  system  A,  suitable  for  3^-inch, 
4^ -inch  and  5-inch  bar  floors.  Stirrups  are  placed  over  the  upper 
girder  flanges,  and  tops  of  slabs  are  flush  with  tops  of  girders. 

There  is  also  another  long  span  system,  called  System  B,  suitable 
for  same  size  bar  floors  as  in  system  A.  Connections  to  girders  are 
made  with  angles  bolted  to  bars  and  girders.  Tops  of  concrete 
slabs  are  flush  with  tops  of  floor  girders. 

Fig.  360  shows  a  perspective  view  of  the  long  span  system  B 
construction,  with  girder  connections,  girder  covering,  and  brick 
wall  connections  for  end  spans. 

Fig.  361  shows  section  of  two-ribbed  bar  with  angle  and  bolt 
connections  for  girders. 

Fig.  362  shows  long  span  system  C,  suitable  also  for  the  same 
size  bar  floor  as  in  systems  A  and  B.  The  bars  are  supported  on 
upper  girder  flanges,  and  bottoms  of  concrete  slabs  are  ^  of  an 
inch  or  i  inch  below  the  tops  of  girder  top  flanges. 

446.  THE  ROEBLING  FLAT  CONCRETE  FLOOR  CON- 
STRUCTION, REINFORCED.— Figs.  363  to  366  show  the  details 
of  this  system  of  flat  concrete  construction,  which  is  intended  to 
meet  the  requirements  of  a  light  and  economical  floor. 


BUILDIXG  CONSTRUCTION.         (Ch.  IX)" 


Fig.  362.    Coliiml)ian  System.    Long  Span.    System  C. 


FIRE-PROOF  CONSTRUCTION— FLOORS. 


Fig.  363  shows  a  general  perspective  view  of  Type  i  of  this  sys- 
tem, with  girder,  beams,  column,  flooring  and  ceiling.  The  flat  con- 
struction is  known  as  System  B,  and  the  arched  construction  as 
■  System  A.  Type  i  consists  of  a  light  steel  framework  imbedded 
in  concrete.  Flat  steel  bars,  about  2  inches  wide  and  from  34  to 
of  an  inch  thick,  are  set  on  edge  and  spaced  16  inches  on  centers, 
with  a  quarter  turn  at  each  end  where  they  rest  upon  the  floor 
beams.  At  suitable  intervals  >^  by  >^-inch  half-oval  steel  "spacers" 
are  placed  to  separate  and  brace  the  bars.  Temporary  wood  center- 
ing is  erected  under  the  latter,  on  which  cinder  concrete,  made  of 
Portland  cement,  sharp  sand  and  clean  steam  cinder,  is  deposited 
to  a  thickness  of  at  least  4  inches.  A  thorough  protection  of  con- 
crete filling  is  placed  around  both  sides  of  the  webs  of  floor  beams 


i'ig-  363.    Roebling  Flat  Construction.     Type  i. 


projecting  above  or  below  the  surfaces  of  the  concrete,  and  sloped 
from  the  edges  of  the  flanges.  A  flat  wire  ceiling,  similar  to  that 
used  with  the  arched  construction,  is  then  put  on  the  under  side  of 
the  floor  beams. 

Stiffened  wire  lath  attached  to  the  under  side  of  the  reinforcing 
bars,  and  employed  also  as  a  centering  for  the  concrete,  may  be 
used,  and  is  occasionally  found  to  be  cheaper  than  wood  centering. 
It  also  allows  the  moisture  to  drip  away,  often  preventing  injury 
from  freezing  in  cold  weather. 

Fig.  364  shows  sections  of  Type  i  with  a  plan  of  the  floor  beams, 
flat  bars  and  spacers.  Type  i  is  used  in  public  buildings,  offices, 
theatres,  churches,  schools,  hotels,  residences,  etc.  Type  i  may  be 
used  without  the  hung  ceiling  and  finished  with  panelling.  Another 
type  also,  known  as  Type  2,  is  used.  It  finishes  with  a  panelled 
ceiling  and  is  adapted  to  stores,  warehouses,  depots,  factories,  etc. 


BUILDING  CONSTRUCTION.         (Ch.  IX)' 


A  flat  ceiling  may  be  used  with  this  Type  2  if  desired^  and  in  this 
case  it  is  known  as  Type  3. 

Fig.  365  shows  a  section  of  Type  4,  with  plan  of  6-inch  I-beams, 
placed  4  feet  on  centers,  with  flat  bars  placed  on  the  lower  flanges 
of  the  beams,  and  with  a  cinder  fill  on  top  of  the  concrete  slab  to 
the  desired  level.  When  wood  centering  is  employed  it  is  placed  as 
shown  by  the  dotted  lines.  Sometimes  the  floor  nailing-strips  have 
no  filling  in  between,  as  shown  on  left  of  section.  Type  4  is  used 
for  apartment-houses,  hotels,  etc.,  and  other  buildings  in  which  a 
light  floor  construction  is  desired.  Spans  for  this  type  are  also 
made  5^  and  6  feet,  with  slight  variations  in  the  details,  but  it  is 
not  desirable  when  the  I-beams  are  more  than  7  inches  deep. 

Fig.  366  shows  a  section  of  Type  5,  in  which  the  bars  are  bent 
down  2  inches  or  more  at  the  middle  of  the  span.  It  is  adapted  to 
buildings  the  floors  of  which  have  light  weights  to  support  and  in 
which  the  fire  risk  is  not  very  great.  It  may  be  used  for  spanning 
the  intervals  between  girders,  omitting  the  intermediate  floor  beams. 
By  making  the  spans  shorter  and  the  construction  heavier,  the 
same  system  can  be  adapted  to  stores  and  warehouses. 

It  has  been  installed  successfully  in  spans  up  to  22  feet,  but 
under  ordinary  conditions,  considering  both  the  fire-proofing  and 
the  steel  work,  the  most  economical  results  are  obtained  when  the 
girders  are  spaced  from  14  to  16  feet  on  centers. 

The  following  are  the  weights,  spacing  of  beamSj  etc.,  for  the 
Roebling  Flat  Floor  System. 


Type  of 
construc- 
tion 

Spacing 
of 
beams 

Depth 

of 
beams 

Thickness 
of 

concrete 

Wt.  per  sq.  ft.  of 
concrete  imbedded 
iron  and  wire 

Wt.  of  ceiling, 
including 
plaster 

No.  of  coats 
of  plaster 
required 

Type  1 
"  2 
"  3 
"  4 

"  5 

8  ft, 

5  ft. 
7  ft. 

6  ft. 

(  up  to 
1  16  ft. 

10  in. 
10  in. 
15  in. 
8  in. 

( 15  to 
1  20  in. 

4inches 
4  " 
4 

4  " 

5}^ 

30  lbs. 
35  " 
38 

28  " 
45  " 

10  lbs. 

9  " 
10  " 

7 

7  " 

3 
2 
3 
2 

2 

In  regard  to  strength,  the  manufacturers  claim  that  Type  i  will 
carry  safely,  with  a  factor  of  safety  of  4,  and  span  of  8  feet,  200 
pounds  per  square  foot ;  and  that  Type  5  will  carry  safely,  with  a 
span  of  16  feet,  100  pounds  per  square  foot. 

447.  THE  BERGER  MULTIPLEX  STEEL  PLATE  FLAT 
CONCRETE  FLOOR  CONSTRUCTION.— Figs.  367,  368,  369 


FIRE-PROOF  CONSTRUCTION— FLOORS.  513 


Fig.  364.     Roebling  Flat  ('onstruction.     Type  i. 
Sections  and  Plan. 


Fig.    365.     Roebling    Flat    Construction.     Type  4. 
Section  and  Plan. 


/ 


Fig.  366.    Roebling  Flat  Construction.     Type  5. 


514 


BUILDING  CONSTRUCTION.  (Ch.  IX> 


and  370  explain  this  flat  concrete  floor  construction,  which  employs 
a  corrugated  steel  plate,  made  by  the  Berger  Manufacturing  Com- 
pany, of  Canton,  Ohio,  and  invented  by  Mr.  G.  Fugman.  The 
plates  are  made  of  different  gauges  of  steel  from  No.  16  to  No.  24, 
No.  18  being  as  heavy  as  would  be  generally  required,  and  they 
may  be  either  black,  painted  or  galvanized.  They  consist  of  a  series 
of  vertical  corrugations  forming  three  half-circle  arches  at  top  and 
bottom,  which  separate  the  vertical  sides  of  the  corrugations  and 
add  stiffness  to  the  upper  and  lower  parts  of  the  plates. 

The  total  depths  of  the  plates,  over  all,  vary  for  different  strengths 
required,  and  are  2,  2^,  3,  3^  and  4  inches;  while  the  horizontal 
widths  or  spaces  between  the  manifolds  or  vertical  sides  of  the 
corrugations  remain  constant  at  2  inches.  The  lengths  of  the 
sheets  vary  up  to  and  including  10  feet. 

The  plates  are  usually  laid  on  top  of  the  floor  beams,  but  may  be 
placed  on  their  lower  flanges.  Concrete  is  filled  in  on  top  and  into 
the  corrugations,  and  levelled  off  to  a  depth  of  i  inch  above  the 
plate  for  the  2-inch  plates,  2  inches  for  the  2i/l-inch  plates,  3  inches 
for  the  3  and  3^-inch  plates  and  4  inches  for  the  4-inch  plates, 
when  the  plates  are  laid  on  top  of  the  beams. 

In  case  the  plates  are  laid  on  the  lower  flanges  of  beams,  the 
concrete  is  filled  in  to  the  tops  of  the  beams  or  higher. 

When  there  are  wood  floors,  the  flooring  strips  for  nailing  are 
imbedded  in  the  concrete  and  the  lower  surface  of  the  strips  are 
kept  above  the  plates  at  a  distance  of  about  ^  an  inch. 

Among  the  advantages  of  this  floor  may  be  mentioned  its  strength 
and  lightness  and  the  omission  of  centering  and  tie-rods ;  and 
among  its  disadvantages,  the  necessity  of  an  independently  con- 
structed ceiling,  if  plastering  underneath  is  required,  and  the  ex- 
posure of  the  metal  ceiling  to  heat  or  fire. 

In  regard  to  its  weight,  strength,  etc.,  the  manufacturers  give 
detailed  data  for  varying  spans  .and  conditions  of  loading ;  but  for 
purposes  of  comparison  it  may  be  stated  that  for  No.  18  gauge, 
4-inch  plates,  filled  with  rock  concrete  to  a  height  of  i  inch  above 
plate  tops,  the  weight  is  about  39  pounds  per  square  foot ;  and  for 
an  8-feet  span,  a  safe  load  of  430  pounds  per  square  foot  is  given. 

Fig.  367  shows  one  section  of  a  Berger  multiplex  corrugated 
steel  plate. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  515 


Fig.  368  shows  the  dimensions  of  these  plates  as  ordinarily  used 
for  floor  arches. 

Fig.  369  shows  a  perspective  of  the  Berger  floor  construction, 
with  the  corrugated  plates  resting  on  top  of  the  upper  flanges  of 
the  floor  I-beams,  and  of  the  concrete  filling,  nailing  strips,  steel 
furring  strips  and  metal  lath  for  a  flat  ceiling. 

Fig.  370'  shows  a  perspective  of  the  floor  construction,  with  plates 
resting  on  the  lower  flanges  of  the  floor  beams,  with  concrete 
brought  up  flush  with  top  surfaces  of  floor  beam  upper  flanges. 

448.  THE  FERROINCLAVE  FLAT  CONCRETE  FLOOR 
CONSTRUCTION. — Figs.  371  to  374  show  the  construction  of 
this  system  of  floors. 

There  are  other  forms  and  patents  of  different  variations  of 


Fig.  367.    Berger  Corrugated  Steel  Plate. 

corrugated  or  dovetailed  section  steel  sheets.  The  one  described 
under  this  heading  is  known  as  "Ferroinclave,"  and  is  used  prin- 
cipally in  the  construction  of  fire-resisting  flooring,  roofing,  siding, 
etc.,  for  factory  buildings,  power-plants  and  the  like.  After  it  is 
secured  in  place  it  is  always  coated  on  both  sides  with  Portland 
cement  mortar  or  concrete,  and  becomes  a  reinforced  concrete  con- 
struction. As  an  article  of  manufacture,  as  well  as  a  method  of 
manufacture,  it  is  patented  in  the  United  States  and  foreign  coun- 
tries, and  is  the  invention  of  Mr.  Alexander  E.  Brown,  of  the 
Brown  Hoisting  Machinery  Company  of  Cleveland,  O. 

Ferroinclave  is  generally  made  of  No.  24  U.  S.  gauge  box 


BUILDING  CONSTRUCTION.         (Ch.  IX)' 


annealed  sheet-steel,  each  sheet  being  accurately  crimped  into  the 
dovetailed  section  shown.  The  corrugations  are  ^  an  inch  in  depth, 
2  inches  center  to  center,  with  an  opening  between  the  edges  of 


Fig.  368.    Berger  Corrugated  Steel  Plate.  Dimensions. 


of  an  inch.    They  are  made  wider  at  one  end  of  each  sheet  than 
at  the  other,  so  that  sheets  may,  if  desired,  shingle  or  fit  endwise 
into  each  other ;  or  they  may  be  had  with  non-tapering  corrugations. 
Full-sized  sheets  are  20^  inches  wide  by  10  feet  long;  and  the 


■l^'ig-  369.    Berger  Floor  System.     Plate  on  JJtams. 


covering  width  of  each  sheet,  that  is,  the  distance  from  center  to 
center  of  side  laps,  is  20  inches. 

Among  the  advantages  of  this  type  of  corrugated  sheets  for 
floor  construction  may  be  mentioned  the  small  size  of  the  corruga- 


Fig-  370.    Berger  Floor  System.     Plate  on  Lower  Flange. 

tions  allowing  plastering  on  the  under  side ;  and  a  strength 
sufficient,  with  moderate  spans,  to  hold  the  concrete  without  wood 
centering,  thus  saving  the  cost  of  same,  and  the  time  used  in 
erecting  it  and  taking  it  away. 

Among  the  disadvantages  rnay  be  mentioned  the  increased  cost 
of  the  sheets  on  account  of  transportation  charges,  when  shipped 
any  distance,  making  it  difficult  to  compete,  under  such  conditions. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  s^7 


as  far  as  cost  alone  is  cohcerned,  with  many  reinforced  concrete 
systems. 

The  concrete  mixture  used  for  floors  in  this  system  is  usually  a 
rich  gravel  or  crushed  stone  concrete  of  a  thickness  determined  by 
the  loads  and  span. 

In  regard  to  strength,  tests  have  been  made  on  No.  24  ferroin- 
clave  and  the  ultiitiate  strength  determined  for  different  thicknesses 
of  concrete,  the  span  being  4  feet  10^  inches,  and  the  sheets  being 
20  inches  wide.  The  results  of  the  tests  have  been  tabulated  as 
follows : 

Thickness  of  i  to  2  mortar  above 
the  metal   i>^"  2"    2>4"     3"    S'A"  4" 

Ultimate  strength  in  pounds  per 
square  foot  (span  4  ft.  10^  ins.)  615  915  1220  1560  i860  2120 


Fig.  371.    Ferroiiiclave  Sheet. 


To  get  the  safe  load,  a  factor  of  6  is  generally  used  for  ordinary 
loading. 

In  addition  to  the  uses'  mentioned  already,  ferroinclave  is  em- 
ployed in  the  construction  of  partitions,  stair  treads  and  risers,  gut- 
ters, vats,  tanks,  bins,  fire-proof  doors,  cornices,  moldings,  bridge 
floors,  etc. 

Fig.  371  shows  a  sheet  of  ferroinclave. 

Fig.  372  shows  a  partial  section  of  the  sheets  lapped,  with  cement 
concrete  above  and  plaster  below  the  sheets. 

Fig.  373  shows  section  and  perspective  of  construction  used  for 
segmental  floor  arch. 

^^S-  374  shows  perspective  of  flat  floor  construction,  looking 
down. 


5i8  BUILDING  CONSTRUCTION.  (Ch.  IX) 

448a.  THE  WHITE  CONCRETE  FLOOR  CONSTRUC- 
TION.— Figs.  371,  a,  b,  c,  d  and  e,  show  this  construction,  patented 
and  controhed  by  the  White  Fire-proof  Construction  Company, 
New  York,  and  introduced  into  use  some  years  ago.  This  system 
has  been  used  in  important  buildings  and  is  well  spoken  of,  the 
round  reinforcing  rods  being  correctly  located  in  the  concrete  for 
maximum  tensile  strength  and  general  efficiency.  The  claims  are 
made  that  the  monolithic  character  of  the  concrete  is  not  in  any 
way  destroyed  by  the  presence  of  the  rods,  as  they  occupy  a 
minimum  of  space,  and  that  on  account  of  the  simplicity  of  the 
construction  it  can  be  installed  very  rapidly. 

Figs.  371,  a  and  b,  show  systems  A  and  B,  which  are  types  of 
flat  arches,  with  and  without  metal  lath  and  plaster  ceilings.  There 
is  a  wide  range  of  modifications,  such,  for  example,  as  the  raising 
or  lowering  of  the  slab  to  accommodate  plumbing  pipes,  electrical 
conduits,  etc.  In  cases  where  the  steel  beams  are  spaced  not  more 
than  7  feet  apart  cinder  concrete  is  used.  This  form  of  con-  "i 
struction  has  been  subjected  to  the  severest  fire,  water  and  weight 
tests,  2,350  pounds  having  been  placed  upon  each  square  foot  of 
surface  of  a  floor  arch  of  this  kind  without  causing  any  sign  of 
failure  whatever ;  and  it  lends  itself  particularly  well  for  use  in 
office-buildings,  lofts,  factories,  hotels  and  dwellings. 

Fig.  371,  c,  shows  System  D,  an  adaptation  for  long  spans,  in 
which  stone  replaces  cinders  in  the  mixture,  and  the  reinforcing 
rods  are  spaced  according  to  the  loads  to  be  carried. 

Fig.  371,  d,  shows  System  E,  a  variation  in  which  the  concrete 
slab  is  approximately  flush  with  the  under  side  of  the  floor  beams. 
This  makes  a  flat  surface  ready  for  plastering  without  any  further 
preliminary  work.  In  using  this  form  of  construction  it  is  neces- 
sary to  have  the  under  side  of  the  steel  beams  in  the  same  hori- 
zontal plane,  and,  as  the  space  from  the  top  of  the  arch  to  the 
top  of  the  beams  is  filled  in  with  concrete  cinder  fill,  it  is  desirable 
to  use  only  the  smaller  sizes  of  beams  in  order  to  avoid  excessive 
dead  loads.  This  system  is  particularly  adapted  for  use  in  apart- 
ment-houses, etc. 

Fig.  371,  e,  shows  System  F,  which  includes  several  forms  of  seg- 
mental arches,  with  tension  members  imbedded.  This  form  of 
construction  is  capable  of  carrying  very  large  live  loads,  and  is 
largely  used  in  breweries,  power-houses,  etc.  See  arched  forms 
of  concrete  floor  construction.  Articles  442  and  443. 


FIRE-PROOF  CONSTRUCTION— FLOORS.  519 


Cnoss  Sect/on  W/TH '/jAsTAL.  Lath  CtiL/Nd 
Fig.  371-a.    White  Concrete  Flat  Floor  Arch,   System  A. 


Type  CROSS  SECTION  Type  2 

Fig.  37 1 -b.    White   Concrete   Flat  Floor  Arch,   System  B. 


Fig.  371-C.    White  Concrete  Long  Span  Flat  Floor  Arch,   System  D. 


0/ 

/  ^KousM  rcooR 

Type  3 

Fig.  371-d.    White  Concrete  Flat  Ceiling  Floor  Arch,  System  E. 


Type  4  Type  5 

Fig.  371-e.    White   Concrete    Segmental   Floor   Arch,    System  F. 


520  BUILDING  CONSTRUCTION.         (Ch.  IX> 

449.  UNPATENTED  SYSTEMS  OF  FLAT  CONCRETE 
FLOOR  CONSTRUCTION,  REINFORCED.-Some  of^tife  pa^ 
ented  systems  of  flat  concrete  floor  construction  having  been  con- 


'■•  ;•■  °'vo  .•"••.< :  •°.''?s'*>  <s?>i»K  jscMwf  •  o%° .  i .  o :  i  •  -A 

^J.*  .*  •  *•  *. »  •  •  •  •  V : : ;  >  :'Y 'P'^'q  V: ; 
pfaat«r       • : .  • •  •.•vly.  .•  v;.*.V. 


i^ig.  372.-    Section  Through  Ferroinclave  Floor. 


Fig-  373-    Ferroinclave  Floor  Arch  Syste 


FcTTomcUve  Combination  Centering  and  Reinforcement- 


f*"  s  I  "  Hardwood  strip  \  | 

Fig.   374.-    Ferroinclave  Flat  Floor  System 


1  part  Portland  cement 
Concrete  {  2  parts  sand 

Hair  as  inquired 


sidered,  some  of  the  unpatented  systems  will  now  be  briefly 
referred  to. 

450.  EXPANDED-METAL  FLOOR  REINFORCEMENT  — 
Fig.  375  shows  the  diamond  mesh  expanded-metal  used  in  concrete 


FIRE-PROOF  CONSTRUCTION— FLOORS. 


521 


fire-proof  floor  construction.  Fig.  376  shows  a  section  of  one 
kind  of  expanded-metal  reinforced  floor  with  steel  I-beam  construc- 
tion, and  Fig.  377  shows  a  section  of  floor  with  reinforced  concrete 
beams. 

The  advantages  claimed  for  this  material  for  floor  reinforcement 


Fig-  375-    Expanded-metal.    Diamond  Mesh. 


may  be  enumerated  as  follows:  (i)  a  superior  mechanical  bond 
with  the  surrounding  concrete;  (2)  a  more  advantageous  arrange- 
ment of  the  material  in  the  concrete  than  with  an  equal  amount  in 
any  other  form;  (3)  a  method  of  manufacture  which  results  in  an 


Fig.  376.     Expanded-metal  I-beam  Floor  Construction. 


increased  ultimate  strength  and  high  elastic  limit,  resulting  in  (4) 
the  ^combined  advantages  of  a  high  ultimate  strength  with  a  low- 
carbon  steel;  (5)  a  uniform  distribution  of  small  sections  at  fre- 
quent intervals;  and  (6)  great  efficiency  in  resisting  stresses  devel- 


Fig.  377.-    Expanded-metal  Reinforced  Beam  Construction. 

oped  by  concentrated  loads,  due  to  the  oblique  direction  of  the 
divisions  of  the  mesh. 

Expanded  metal  is  manufactured  from  soft,  tough  steel,  fine  in 
texture,  and  of  a  thickness  which  varies  from  No.  16  to  No.  4, 
Stubbs'  gauge.  The  length  of  the  sheets  of  metal  is  8  or  12  feet, 
and  the  width  varies,  according  to  the  width  of  the  mesh,  from  3 


522 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


to  6  feet.  In  floor  construction  the  3-inch  mesh  is  generally  used, 
the  width  of  the  diamond-shaped  openings  determining  the  designa- 
tion of  the  mesh. 

451.  LOCK-WOVEN  FABRIC  FLOOR  REINFORCE- 
MENT.— Figs.  378  to  381  show  the  character,  form  and  use  of  the 
lock-woven  steel  fabric  employed  in  fire-proof  concrete  floor  con- 
struction, and  manufactured  and  sold  by  W.  N.  Wight  &  Company, 
New  York.  There  are  a  great  many  forms  of  floor  arches  that  can 
be  constructed  with  the  use,  of  this  reinforcement,  most  of  them 
being  patented;  but  any  one  using  it  may  adopt  any  form  desired. 
One  of  the  advantages  of  this  fabric  is  the  stretching  or  extending 
from  wall  to  wall,  making  a  continuous  tie.  It  can  be  obtained 
either  ''bright"  or  galvanized,  the  latter  costing  cents  more  per 
square  yard  than  the  former ; .  and  it  can  be  woven  of  any  gauge 
wire  and  with  any  size  mesh,  oblong  or  square. 

The  width  of  the  ''standard"  fabric  is  56  inches,  but  it  can  be 
increased  up  to  88  inches ;  and  it  is  put  up  in  rolls  of  from  330  to 
500  lineal  feet ;  or  less,  if  required. 

High  carbon  steel  wires  crossing  each  other  at  right-angles,  as 
shown  in  Fig.  378,  are  used  in  the  weaving,  the  longitudinal  strands 
in  the  standard  fabric  being  of  No.  10  wire,  B.  &  S.  gauge,  placed 
4  inches  on  centers,  and  the  cross  strands  being  of  No.  9  wire, 
placed  6  inches  on  centers.  The  crossing  strands  are  locked  at  the 
intersections  with  No.  9  wire  twisted  around  as  shown  in  the  detail 
in  Fig.  378.  The  weight  of  the  standard  fabric  is  two-tenths  of  a 
pound  per  square  foot. 

Figs,  379',  380  and  381  show  three  of  many  systems,  with  spans, 
loads  and  tests  indicated.  Fig.  379  showing  a  panelled  ceiling.  Fig. 
380  a  flat  ceiling  and  Fig.  381  a  special  design  for  light  floors  on 
wide  spans. 

The  catalogues  of  the  manufacturers  give  detailed  data  regarding 
the  strength  of  the  various  systems,  and  the  approved  tests. 

452.  STEEL-WIRE  FLOOR  REINFORCEMENT.— Figs. 
382  and  383  show  the  general  form  of  the  steel  wire  fabric  used 
for  the  reinforcement  of  fire-proof  floors,  and  manufactured  by  the 
American  Steel  and  Wire  Com.pany,  of  Chicago,  Fig.  382  showing 
the  "triangular  mesh"  and  Fig.  383  showing  the  "square  or  rectang- 
ular mesh." 

The  triangular  mesh  steel  wire  reinforcement  is  particularly 


FIRE-PROOF  CONSTRUCTION— FLOORS.  523 


adapted  to  floor-slabs,  curtain  and  retaniing-walls,  bridge  spans  and 
reservoirs;  and  the  square  mesh  steel  wire  reinforcement  is  par- 
ticularly adapted  to  concrete  columns,  water  mains  and  sewers. 

The  longitudinal  or  tension  members  .of  the  triangular  mesh  rein- 
forcement are  made  either  stranded  or  solid,  and  the  triangular  form 
of  mesh  is  manufactured  in  rolls  of  approximately  150-,  300-  and  600- 
feet  lengths,  and  in  standard  widths  of  from  18  to  58  inches.  The 
distance  on  centers  of  the  longitudinal  or  tension  members  is  usually 
4  inches,  and  the  distance  on  centers  of  the  diagonal,  bond  or  cross- 
members  either  2  or  4  inches  as  desired. 

The  above  data  apply  also  to  the  square  or  rectangular  mesh 
steel  wire  reinforcement,  except  that  the  cross  or  bond  wires  are 
spaced  4,  6  or  12  inches  apart. 

This  steel  wire  reinforcement  is  not  as  a  rule  galvanized,  as  * 
there  is  a  stronger  bond  between  the  steel  and  the  concrete  when  the 
galvanizing  is  omitted.    The  manufacturers  will  furnish  the  wire  , 
galvanized,  however,  if  so  desired. 

They  ofifer  88  stock  styles  of  the  triangular  mesh  and  28  styles 
of  the  square ;  and  furnish  detailed  data  regarding  strength,  tables, 
formulas,  illustrations  of  application,  weights  per  square  foot,  cross- 
sectional  areas  of  wires,  total  cross-sectional  area  of  reinforce- 
ment, etc. 

453.  WELDED  METAL  FABRIC  OR  MESH  FLOOR  RE- 
INFORCEMENT.— Fig.  384  shows  the  general  form  of  this  kind 
of  reinforcement,  and  Fig.  385  shows  in  detail  a  piece  of  the  elec- 
trically welded  fabric  so  cut  as  to  expose  the  weld  between  the 
longitudinal  and  transverse  wires.  It  is  claimed  by  the  manufac- 
turers that  it  is  not  possible  to  detect  the  point  of  junction  between 
the  two  wires  on  account  of  the  perfect  weld.  This  fabric  is  made 
by  the  Clinton  Wire  Cloth  Company,  of  Clinton,  Mass. ;  and  the 
principal  advantages  claimed  for  it  for  floor  slab  construction  are 
the  adaptability  to  variations  in  size  and  spacing  of  wires  to  give  the 
necessary  area  for  any  given  weight  and  span;  the  coincidence  of 
the  direction  of  the  wires  with  the  line  of  stress,  thus  diminishing 
the  tendency  to  any  distortion  of  the  rectangles  of  the  mesh ;  and 
the  rigid  holding  in  place  of  the  carrying  wires  by  the  cross  wires 
welded  to  them,  and  the  consequent  prevention  of  the  slipping  of 
the  former  in  the  concrete. 

This  form  of  reinforcement  has  been  extensively  employed  for 


524 


BUILDING  CONSTRUCTION.         (Ch.  IX)- 


Fig.  378.    Lock- woven  Fabric. 


Fig.  379.    Lock-woven  Fabric  Floor  Construction. 


Fig.  380.    Lock-woven  Fabric  Floor  Construction. 


Fig.  381.    Lock-woven  Fabric  Floor  Construction.    Wide  Span. 


FIRE-PROOF  CONSTRUCTION— FLOORS  525 


all  kinds  of  concrete  construction,  The  sizes  of  meshes  and  wires 
vary  through  a  wide  range,  usual  meshes  being  from  i  to  4  inches 
on  centers,  with  from  No.  10  to  No.  3,  Washburn  and  Moen  gauge. 


Fig.   382.    Steel    Wire  Reinforcement.     Triangular  Mesh. 


for  the  carrying  wires,  and  from  No.  11  to  No.  6,  placed  from  3 
to  12  inches  on  centers  for  the  distributing  wires. 

The  material  is  sold  in  long  rolls  varying  in  width  from  48  to 
86  inches,  and  when  it  is  laid  over  the  tops  of  the  floor  beams  laps. 


Fig-  383-    Steel  Wire  Reinforcement.    Square  Mesh. 


and  joints  are  avoided,  and  a  continuous  metal  bond  extends  from 
wall  to  wall. 

Tests  for  strength  have  given  exceedingly  satisfactory  results. 


526 


BUILDING  CONSTRUCTION..         (Ch,  IX)' 


and  especially  so  when  compared  with  the  lightness  of  the  material, 

454.  THE  MERRICK  SYSTEM  OF  CONCRETE  FLOOR 
-ARCH  CONSTRUCTION.— Figs.  386  and  387  show  the  general 
■cQnstruction  of  this  reinforced  flat  concrete  floor  system^  which  is 
controlled  by  Mr.  Ernest  Merrick,  New  York. 

The  figure  shows  what  is  known  as  construction  ''A,"^  the  form 
used  for  ordinary  spans.  In  the*  long-span  construction  "B/'^  two 
13/16-inch  reinforcing  rods  are  used  in  the  concrete  ribs  between 
the  metal  fabric  forms,  one  of  the  rods  running  horizontally  m  the 
lower  part  of  each  concrete  rib  and  the  other  rod  running  horizon- 
tally and  next  to  and  parallel  to  the  first,  through  about  one-third 
of  the  span,  and  then  curving  up  to  the  upper  part  of  the  concrete 
ribs  and  running  horizontally  into  the  concrete  part  of  the  floor 
system  over  the  walls  or  bearings,  following  thus,  approximately 
the  "bending  moment  curve.''  This  latter  form  has  been  employed 
in  spans  of  16  and  18  feet,  the  floor  being  built  from  girder  to 
girder,  doing  away  with  all  steel  I-beams,  and  proving  satisfactory 
and  economical. 

This  type  of  flooring  consists  of  a  series  of  reinforced  concrete 
beams  connected  as  shown  by  a  concrete  plate  at  the  top  and  a  con- 
crete ceiling  plate  at  the  bottom,  the  width  of  the  span  aad  the 
amount  of  the  load  determining  the  size  of  the  concrete  beams  and 
the  percentage  of  reinforcement. 

The  lower  or  ceiling  slab  is  always  made  of  cinder  concrete,  as  it 
is  a  better  fire-resisting  material  than  stone  concrete ;  and  in  the 
long-span  construction  the  upper  concrete  slab  part  is  made  of  stone 
concrete  for  greater  strength. 

A  flat  wooden  centering  is  put  up  first,  and  on  it  is  placed  a 
2-inch  thickness  of  cinder  concrete.  Before  the  latter  has  fully 
set,  wire  lath  or  sheet  metal  cores  or  cages,  without  bottoms,  and 
made  of  very  inexpensive  material,  are  put  in  position  on  it,  the 
lower  edges  thus  becoming  imbedded.  These  fabric  cores  are  left 
in  place,  the  reinforcing  rods  set  and  the  concrete  filled  in  between 
and  above  the  fabric. 

The  disadvantages  are  the  necessity  of  a  uniform  spacing*  of  the 
floor  beams ;  greater  cost  of  factory  forms  than  of  centering  in  place 
at  the  building;  the  use  of  a  richer  and  more  carefully  prepared 
concrete  mixture,  necessitated  by  the  extra    strength  required 


FIRE-PROOF  CONSTRUCTION— FLOORS.  527 

in  pieces  to  be  handled ;  and  the  loss  by  breakages  during 
transporta^iion. 

c.    3.    SECTIONAL  CONCRETE  FLOOR  CONSTRUCTION. 

455.  GENERAL  DESCRIPTION.— This  is  the  third  division 
of  the  concrete  fire-proof  floor  construction.    The  general  principle 


n     n  \ 

I 

i- 

! 

1 

. 

1 

1 

\ 

1  1 

1  II 

Fig.  384.    Welded-metal  Fabric. 


of  this  type  of  fire-proof  floor  construction  is  a  factory-made  unit, 
completely  finished  and  then  taken  to  the  building  and  set  in  place 
between  the  steel  floor  beams. 

The  advantages  of  this  system  are  the  saving  of  the  labor  and 
expense  of  centering,  little  or  no  centering  being  used ;  the  greater 
assurance  of  a  uniform  and  perfect  mixture  of  concrete  materials 


Fig.  385.    Welded-metal  Fabric.  Detail. 


by  more  skilled  labor  at  the  factory ;  and  a  consequent  additional 
saving  of  time. 

456.  THE  "HOLLOW  CONCRETE  1-ARCH"  FLOOR 
CONSTRUCTION. — Fig.  388  shows  one  type  of  sectional  con- 


528  '  BUILDING  CONSTRUCTION.         (Ch.  IX) 


FIRE-PROOF  CONSTRUCTION— FLO.SrS.  529 


Crete  floor  construction,  commonly  called  the  ''Hollow  Concrete 
I-arch,"  or  the  "End-construction  Concrete  Tile,"  and  made  and 
used  by  the  Standard  Concrete  Steel  Company  of  New  York.  The 
figure  shows  also  two  types  of  beam  covering  and  flange  protec- 
tion. The  concrete  I-beams,  which  are  made  at  the  factory  and 
thoroughly  hardened  before  being  sent  to  the  building,  are  10  or 
12  inches  deep,  and  have  their  lower  flanges  reinforced  with  either 
steel  rods  or  channels,  around  which  the  concrete  is  compacted  by 
special  machinery.  The  steel  I-beams  are  spaced  from  5  to  7  feet 
apart,  and  on  their  lower  flanges  rest  the  concrete  I-beams,  the 


latter  being  set  about  12  inches  apart,  and  having  their  lower 
flanges  and  the  spaces  between  them  filled  in  with  a  cinder  concrete 
of  a  similar  mixture  to  that  of  the  concrete  I's  themselves. 


The  ceiling  is  level,  and  the  webs  of  the  steel  I-beams  are  pro- 
tected, as  shown,  between  the  concrete  Fs  by  concrete,  which  is 
used  also  to  fill  in  at  the  ends  of  the  concrete  I's,  where  inequalities 
in  lengths  occur.  Some  small-mesh  metal  fabric  is  placed  over  the 
tops  of  the  concrete  I's,  and  on  this  the  concrete  slabs,  cement 
tiles,  terrazzo  on  concrete  fill,  or  wood  flooring  on  sleepers,  as 
desired. 

457.    THE  THATCHER   FLOOR   UNIT   SYSTEM.— One 


530 


BUILDING  CONSTRUCTION,         (Ch.  IX)- 


type  which  may  be  mentioned  as  giving  a  very  light,  strong  and 
economical  floor  is  the  sectional  floor  system  made  by  the  Concrete 
Steel  Engineering  Company,  of  New  York,  and  called  the  "Thatcher 
Floor  Unit."  These  units  of  concrete  are  made  for  any  required 
load  or  span;  cast  in  suitable  molds,  usually  about  2  feet  in  width, 
or  in  any  width  convenient  for  hauling;  allowed  to  harden  or  set 
at  the  factory  for  a  month  or  two,  and  then  brought  to  the  build- 
ing, set  in  place  and  dovetailed  together  with  cement  mortar. 

458.  OTHER  SYSTEMS  OF  SECTIONAL  CONCRETE 
FLOOR  CONSTRUCTION.— There  are  several  types  of  sectional 
concrete  floor  construction,  some  of  which  have  not  been  very  suc- 
cessful commercially,  and  are  no  longer  on  the  market. 

3.    BEAM  AND  GIRDER  PROTECTION. 

459.  GENERAL  CONSIDERATIONS.— The  metal  to  be 
covered  and  protected  may  be  either  a  simple  steel  floor  beam  or  a 
girder;  and  the  girder  may  be  a  single,  double  or  triple  I-beam 
girder,  a  plate-girder  or  a  box-girder.  The  principal  materials  used 
for  covering  and  protecting  are  either  terra-cotta  or  concrete.  The 
terra-cotta  may  be  dense,  semi-porous  or  porous,  and  the  concrete 
may  be  made  of  stone,  cinders  or  slag.  The  terra-cotta  incasing 
blocks  may  belong  to  either  one  of  two  types  of  construction ;  to 
the  one  in  which  the  blocks  incasing  the  lower  flanges  of  the  steel 
beams  meet  below  and  at  the  middle  of  the  flange,  or  to  the  one 
in  which  the  blocks  cover  the  edges  only  of  the  lower  flanges,  and 
hold  up  with  their  bevelled  edges  pieces  of  flat  tile  against  the 
under  side  of  the  steel  beams.  The  beams  or  girders  may  or 
may  not  project  below  the  floor  construction. 

Plaster  composition  material  is  not  recommended  for  beam  and 
girder  protection,  and  the  use  of  hung  ceilings  for  the  purpose  only 
of  such  protection  is  not  considered  good  practice.  Recent  large 
conflagrations  have  shown  that 'such  ceilings  are  apt  to  come  off 
and  expose  the  beams  or  girders. 

It  is  customary  to  employ  the  same  material  for  the  covering  of 

the  beams  and  girders  that  is  used  for  the  construction  of  the  floor 
arches  or  slabs  themselves. 

All  the  metal  used  in  the  construction  and  support  of  fire-proof 
floors,  including  all  parts  of  steel  beams  and  girders,  should  be 
thoroughly  and  permanently  covered  and  protected ;  and  while  there 


FIRE-PROOF  CONSTRUCTION— FLOORS.  531 


are  most  excellent  systems  of  terra-cotta  fire-protection,  aside  from 
any  questions  of  fire-resisting  properties  of  the  materials  them- 
selves, it  is  generally  admitted  that  a  more  thorough  incasing  of  the 
webs  and  lower  flanges  of  beams  and  girders  can  be  effected  by  the 
use  of  concrete.  The  superior  fire-resisting  properties  of  cinder 
concrete  are  well  known,  and  when  the  incasing  portion  has  suffi- 
cient thickness,  2  inches  or  more,  and  is  put  in  place  with  sufficient 
care,  it  will  remain  securely  in  position  without  the  aid  of  reinforce- 
ment. When  less  than  2  inches  thick,  metal  fabric,  imbedded,  is 
put  around  the  flanges. 

Some  of  the  types  of  floor  construction  are  those  in  which  such 
construction  itself  incases  the  sides  of  the  I-beams,  and  in  which  the 
ceilings  are  not  panelled ;  while  there  are  other  types  in  which  part 
of  the  floor  I-beams  project  below  the  floor  construction,  and  in 
which  the  ceilings  are  panelled.  These  different  types  are  indicated 
in  the  preceding  figures  of  floor  aiches.  In  the  former  case  the 
beam  incasing  should  have  a  minimum  thickness  of  i  inch  and  in 
the  latter  case  it  should  have  a  minimum  thickness  of  inches. 

460.  TERRA-COTTA  BEAM  AND  GIRDER  PROTEC- 
TION.— A.  Beam  Protection. — The  first  type  is  the  one  in  which 
the  incasing  tile  blocks  meet  under  the  lower  flanges  of  the  steel 
I-beam.  Figs.  312,  313,  314,  315,  316,  322,  328,  330,  331,  332,  etc., 
show  various  forms  and  variations  of  this  type.  These  incasing 
blocks  may  be  either  the  floor  arch  skew-backs  or  separate  blocks. 
The  entire  I-beam  may  be  covered  by  the  terra-cotta  blocks,  as  in 
those  systems  in  which  the  floor  tiles  run  over  the  I-beams  with 
some  reinforcing  material  between  them  and  the  beams,  like  the 
^'Johnson"  arch,  for  example. 

The  second  type  is  the  one  in  which  the  incasing  tile  blocks  cover 
the  I-beam  flange  edges  only,  holding  up  by  their  own  bevelled 
edges  pieces  of  flat  tile  against  the  under  side  of  the  metal  flange. 
Figs.  319,  324,  329,  334,  etc.,  show  various  forms  of  this  type. 

B.  Girder  Protection. — Figs.  389  and  390  show  typical  methods 
of  protecting  box-girders  and  double  I-beam  girders  with  hollow 
terra-cotta  blocks ;  and  Fig.  391  shows  a  method  for  a  single-beam 
girder  which  comes  at  the  side  of  a  hatchway  or  other  similar 
opening  in  a  floor.    See  also  other  figures. 

When  girders  project  below  the  ceiling  line,  as  is  usually  the 
case,  they  should  have  ample  protection  because  of  their  great 


532 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


D  no  Q 


390.    -Tile  Protection  for  Double  I-beam  Girder. 


Fig.  391.    Tile  Protection  for  Single  I-beam  Girder. 


FIRE-PROOr  COXSTRUCTION— ROOFS.  533 


exposure  to  the  heat  and  water  accompanying  a  serious  fire  in  the 
building.  For  the  best  resuks  the  minimum  thickness  of  the  terra- 
cotta protection  should  be  4  inches  on  the  sides  and  ly?  inches 
under  the  lower  flanges  of  the  girder,  and  there  should  also  be  a 
space  of  about  J4  of  an  inch  between  the  beam  and  the  tiles.  As 
an  extra  precaution  and  to  prevent  the  side  flange  tiles  from  spread- 
ing, wire  ties  are  inserted  in  the  holes  shown  in  Fig.  389,  and 
placed  in  the  opposite  end-joints  of  the  soffit  tiles. 

461.  CONCRETE  BEAM  AND  GIRDER  PROTECTION. 
— A.  Beam  Protection.— Figs.  349,  350  and  353  show  different 
forms  and  variations  of  this  kind  of  beam  protection,  Fig.  353 
showing  a  soffit  air-space  for  additional  security  against  the  effects 
of  great  heat. 

B.  Girder  Protection. — Many  of  the  figures  drawn  to  illustrate 
concrete  beam  protection  illustrate  also  girder  protection.  The 
methods  employing  the  air-space  are  especially  recommended  for 
girders,  and  have  shown  good  results  in  some  test  cases.  An 
illustration  showing  one  of  the  typical  Roebling  methods  of  cinder 
concrete  girder  protection  is  given  in  Fig.  392. 

4.    FIRE-PROOF  FLOORING. 

462.  GENERAL  DESCRIPTION.— The  building  laws  of 
some  cities  require  that  in  all  buildings  a  certain  number  of  feet  in 
height,  usually  150  feet  or  over,  the  floor  coverings  shall  be  either 
of  wood  treated  by  some  fire-proofing  process,  or  of  some  incom- 
bustible material,  such  as  cement,  tile^  stone,  marble  or  approved 
fire-proof  composition. 

While  in  many  kinds^of  buildings,  aside  from  questions  of  fire- 
resistance  and  durability,  ivood  is  a  more  desirable  material  for 
flooring,  because  of  its  relative  warmth  and  softness,  still  for  many 
other  kinds  of  buildings  the  other  materials  mentioned  are  appro- 
priate and  have  been  widely  used. 

Cement  floors  are  used  in  such  buildings  as  factories  and  ware- 
houses, and  in  the  %uest-rooms  of  many  hotels,  in  which  last  case 
the  carpets  are  laid  over  the  cement  and  tacked  to  bordering  of 
wood  strips. 

Tiles  of  various  materials  are  used  in  public  rooms,  halls  and 
corridors,  and  asphaltic  flooring  also  is  often  employed. 

There  are  numerous  makes  of  composition  flooring  on  the  market 


534 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


which  have  been  used  in  many  recent  buildings  with  more  or  less 
success.  The  result  striven  for  in  their  manufacture  is  to  obtain  a 
.flooring  material,  generally  in  the  form  of  a  dry  powder,  which, 
when  properly  mixed  with  specially  prepared  liquids  and  spread 
over  a  surface,  will  make  a  smooth  floor  without  joints,  of  almost 
any  color,  with  sufficient  resistance  to  wear,  fire-resisting,  non- 
absorbent,  elastic  and  of  reasonable  cost.  An  added  advantage  in 
their  use  is  the  possibility  of  carrying  the  material  up  the  side 
walls,  with  a  small  cove  or  ''sanitary  base"  at  the  floor  angles,  thus 
making  one  continuous  jointless  surface. 

These  composition  floors  are  composed  of  different  mixtures  con- 
taining such  materials  as  asbestos,  magnesite,  sawdust,  sand,  mag- 


Fig.    392.    Cinder   Concrete    Girder  Protection. 


nesium  chloride,  etc.,  and  are  sold  under  various  names,  such  as, 
for  example:  ''Alignum,"  ''Asbestolith,*  ''Asbestos  Granite," 
"Carborundum,"  "Crown  Sanitary  Flooring,"  "Karbolith."  "Lig- 
nolith,"  "Magnesia  Building  Lumber,"  "Monolith,"  "Puritan," 
"Rex,"  "Sanitas,"  etc. 

5.    FIRE-PROOF  ROOFS  AND  ROOF-COVERINGS. 

463.  A.  FIRE-PROOF  ROOFS.  GENERAL  CONSIDERA- 
TIONS.— Roofs  in  this  division  of  the  subject  may  be  considered 
under  the  headings  of  Flat  Roofs  and  pitched  Roofs,  and  the  latter 
may  be  again  conveniently  subdivided  into  the  ordinary  Pitched 
Roofs,  Mansard  Roofs  and  Trussed  Roofs. 

The  details  of  construction  of  fire-proof  fiat  roofs  and  of  fire- 


FIRE-PROOF  CONSTRUCTION— ROOFS.  535 


proof  floors  are  practically  the  same,  about  the  only  dif¥erence  being, 
in  the  case  of  roofs,  lighter  beams  and  arches  or  fillings,  and  a 
setting  of  the  steel  framing  out  of  level  to  obtain  a  slight  pitch. 

The  material  for  the  roof  arches  or  panels  may  be  terra-cotta  or 
concrete  as  for  floors,  put  in  place  in  the  same  way. 

The  question  of  protection  against  damage  by  fire  should  receive 
careful  consideration  in  roof  construction,  and  all  metalwork,  in 
the  roof  space,  such  as  steel  beams,  channels,  girders,  columns,  etc., 
should  be  well  covered  with  approved  protecting  materials. 

The  details  of  ordinary  pitched  roofs  of  fire-proof  construction 
vary  with  the  roof-panel  materials  and  the  covering  of  the  same. 
The  fire-proofing  material  may  be  terra-cotta  blocks  with  or  with- 
out reinforcing,  or  reinforced  concrete.  The  ordinary  terra-cotta 
floor  blocks  and  I-beams  may  be  used  with  floor-arch  construction ; 
or  terra-cotta  ''book-tiles"  or  roofing  tiles  may  be  set  on  and 
between  T-iron  purlins,  placed  horizontally  on  the  I-beam  rafters. 
Any  system,  also,  of  reinforced  concrete  or  of  reinforced  terra- 
cotta tiles  may  be  employed  without  purlins. 

The  rafters  and  all  other  metal  should  be  amply  protected  with 
proper  coverings,  with  terra-cotta  in  the  case  of  terra-cotta  roofs 
and  with  concrete  and  metal  lath  in  the  case  of  concrete  roofs. 
When  the  purlin  construction  is  used  it  is  difficult,  if  not  impossible, 
to  thoroughly  protect  the  purlins   without  great  expense. 

The  details  of  the  mansard  type  of  protected  fire-proof  roofs 
differ  somewhat  from  those  of  the  ordinary  pitched  roofs.  The 
spacing  of  the  steel  rafters,  which  are  generally  secured  to  metal 
wall-plates  by  bolts  or  rivets,  depends  upon  the  fire-proofing 
material  used.  This  material  may  be  terra-cotta  in  the  form  of 
hollow  partition  tiles,  or  concrete,  or  tile  blocks  in  single  lengths 
between  rafters.  The  spacing  on  centers  of  the  rafters  is  from 
5  to  6  feet  for  partition  tile  or  concrete,  and  the  maximum  spacing 
for  single-length  blocks  is  2  feet. 

Trussed  Roofs  also  may  be  constructed  with  the  fire-proof  roof 
materials  either  extending  from  truss  to  truss  and  connected  directly 
with  the  steel  angle,  channel,  etc.,  truss  rafter  members ;  or  placed 
between  or  over  horizontal  steel  purlins  of  various  shapes  resting 
on  the  truss  rafters. 

But  while  the  roof-panels  and  coverings  may  be  fire-proof,  the 
roof  structure  as  a  whole  cannot  be  so  considered  unless  all  the 


536 


BUILDING  CONSTRUCTION, 


(Ch.  IX) 


metal  of  the  trusses  is  protected  in  some  approved  manner.  While 
it  is  possible  to  cover  the  truss  members  with  terra-cotta  or  con- 
crete coverings,  it  is  not  always  attempted,  on  account  of  the 
expense.  In  open  truss  roofs  the  trusses  are  commonly  left  unpro- 
tected, and  where  they  are  enclosed  with  a  ceiling,  that  alone  usually 
serves  as  the  protection  against  fire. 

Fig.  393  shows  typical  book-tiles  for  roofs.  They  are  usually 
made  in  3-  and  4-inch  thicknesses,  in  12-inch  widths  and  in  18-,  20- 
and  24-inch  lengths.  Solid  porous  terra-cotta  blocks  of  about  the 
isame  shapes  and  sizes  are  used  in  a  similar  manner  in  place  of  the 
hollow  tiles,  when  the  roof  covering  is  of  slate  or  clay  tiles,  as 
they  hold  nails  better.  Fig.  394  shows  one  type  of  mansard  roof 
construction,  with  5-inch  I-beams  and  diagonal  or  straight  setting* 
of  blocks,  which  are  grooved  for  one  or  both  flanges  of  the  beams. 
Fig.  395  shows  a  concrete  arch  fire-proof  roof  construction  and 
also  a  suspended  ceiling.  Fig.  396  shows  pitched  roof  construction 
on  trusses,  with  purlins  spaced  from  5  to  8  feet  apart,  expanded- 
metal,  and  slates  nailed  directly  to  cinder  concrete.  Fig.  397  shows 
pitched-roof  construction  on  trusses,  without  purlins,  and  with 
application  of  reinforced  concrete  with  the  Kahn  trussed  bar  in 
connection  with  hollow  tile. 

464.  B.  ROOF  COVERINGS  FOR  FIRE-PROOF  ROOFS. 
— The  principal  materials  used  for  the  coverings  of  fire-proof  roofs 
are,  for  pitched  roofs:  i.  Tin  or  copper;  2.  Roofing  slate;  3.  Clay 
tiles;  4.  Metal  tiles.  For  flat  roofs  the  materials  are:  i.  Tar  and 
gravel ;  2.  Asphalt  with  gravel  or  with  sand ;  3.  Vitrified  tiles  or 
slate  tiles  or  bricks  over  tarred  felt.  Tin  or  copper  may  be  used  on 
flat  roofs  which  are  not  to  be  walked  over. 

When  tin  or  copper  is  used,  wood  nailing-strips  are  imbedded 
in  the  concrete  or  the  concrete  filling,  and  a  wood  sheathing  is  laid 
in  order  to  prevent  the  metal  roof  covering  from  being  destroyed 
by  rust. 

(Ordinary  roofing  slate  is  frequently  used  for  pitched  roofs.  It 
will  not  stand  exposure  to  fire  to  the  same  extent  as  will  clay  tiles 
of  the  best  make  and  design.  The  slates  may  be  nailed  directly  to 
solid  porous  terra-cotta  blocks,  or  to  cinder  concrete,  but  not  to  dense 
tiling  nor  to  rock  or  gravel  concrete. 

Regarding  the  nailing,  the  same  may  be  said  for  clay  tiles  as 
for  metal  tiles. 


FIRE-PROOF  CONSTRUCTION— ROOFS. 


Fig.  393.    Terra-cotta  Book-shape  Roof  Tiles. 


Fi«'  394-    Tile  Construction  for  Mansard  Roofs. 


Fig.  395.    Concrete  Arch  Roof  Construction  and  Hung  Ceiling. 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


Fig.  397.    Concrete  and  Tile  Roof  Construction. 


FIRE-PROOF  COXSr RUCTION— CEILINGS. 


Gravel  roofing  with  tar  or  asphalt  is  not  used  on  roofs  which 
have  an  inclination  of  more  than  ^  of  an  inch  to  i  foot.  Although 
roofs  made  with  these  materials  have  to  be  renewed  every  ten  or 
twelve  years,  they  are  generally  considered  as  satisfactory  cover- 
ings when  the  felt  and  distilled  pitch  and  asphalt  used  are  of  the 
best  quality ;  and  they  also  rank  among  the  most  inexpensive  roof 
coverings  for  fire-proof  buildings.  The  felt  is  put  down  directly 
on  the  concrete,  the  construction  not  differing  any  from  that  used 
over  wood. 

Many  architects  are  of  the  opinion  that  vitrified  or  slate  tiles 
when  laid  over  four  or  five  plys  of  tarred  felt  are  the  best  materials 
to  use  for  flat  roofs  of  fire-proof  buildings. 

The  dimensions  of  the  vitrified  tiles  are  about  8  by  8  by  13^ 
inches,  and  of  the  slate  tiles  12  by  12  by  i  inch.  The  tiles  are 
laid  in  cement  mortar  on  the  felt,  which  is  put  down  and  mopped 
over  the  same  as  for  gravel  roofs. 

6.    SUSPENDED  CEILING  CONSTRUCTION  IN  FIRE-PROOF 

BUILDINGS. 

465.  GENERAL  DESCRIPTION.— In  ofifice-buildings  having 
flat  roofs  there  is  generally  an  air-space  or  attic  between  the  roof 
and  ceiling  of  the  upper  story,  varying  from  3  to  5  feet  in  height. 
This  space  is  often  utilized  for  running  pipes,  wires,  etc.  Build- 
ings having  pitched  roofs  necessarily  require  a  ceiling  below  to 
give  a  proper  finish  to  the  rooms  in  the  upper  story  and  to  make 
these  rooms  comfortable.  In  office-buildings  the  ceiling  under  the 
roof  is  generally  of  a  similar  construction  to  that  of  the  floors, 
although  with  some  systems  only  the  suspended  ceiling  slabs  are 
required  between  the  roof  beams,  and  the  latter  may  be  made  very 
light. 

Under  pitched  roofs  generally,  and  under  flat  roofs  occasionally, 
suspended  ceilings  are  used.  T-bars,  usually  3  by  3  inches  in  size,  are 
hung  from  the  roof  construction  by  means  of  light  rods,  and  the 
ceiling  constructed  either  with  wire  or  expanded-metal  lathing  laced 
to  light  angles  or  to  flat  bars  placed  between  the  T's,  or  with  thin 
tiles  of  semi-porous  or  porous  terra-cotta.  The  shape  of  the  tiles 
should  be  such  that  they  will  drop  below  the  flanges  on  the  T's,  so 
as  to  protect  the  metal. 

Fig.  398  shows  a  section  of  porous  ceiling  tiles  and  Fig.  399  of 
semi-porous  ceiling  tiles.    The  width  of  the  porous  tiles  is  16  inches 


540 


BUILDING 


CONSTRUCTION. 


(Ch/IX) 


for  2-inch  tiles,  and  i8,  20  and  24  inches  for  3-inch  tiles.  The 
2-inch  tiles  weigh  11  pounds  and  the  3-inch  tiles  15  pounds  per 
square  foot,  exclusive  of  the  plastering.  The  tiles  shown  in  Fig. 
399  are  3  inches  thick  and  weigh  4^  pounds  per  square  foot. 

Suspended  ceilings  of  wire  lath  and  plaster  weigh  only  about  12 
pounds  per  square  foot,  including  the  plastering. 

Whether  tile  or  metal  lathing  is  used  for  the  ceiling,  the  webs  of 


Fig.  398.     Typical  Solid  Porous  Ceiling  Tile. 


the  T's  should  be  covered  with  plaster  or  cinder  concrete,  to  protect 
them  from  heat. 

See  also  Fig.  395,  which  indicates  one  form  of  construction  of 
suspended  ceilings,  with  i  by  3/16-inch  hangers,  by  3/16  flat 
irons,  wire  lathing  and  plaster,  and  Y^-'mch.  steel  rods  woven  into 
the  lathing  to  stiffen  it. 

Fig.  400  shows  some  detail  sections,  through  suspended  ceilings 
under  roof,  with  metal  lath  and  plaster  and  i  by  f^^^-inch  hang- 
ers bolted  to  i^-inch  angle-irons.  Type  i  shows  the  ceiling  hung 
from  i-inch  channel-irons  by  the  ''White"  patent  clip,  and  type  2 
shows  it  hung  from  i-inch  angle-irons  by  ^-inch  bolts.  The 
*'White"  clips  are  made  by  the  White  Fire-proof  Construction 
Company,  of  New  York. 

Other  patented  clips  for  fastening  angle-  and  T-bars  to  I-beams 


I'ig-  399-    Typical  Hollow  Ceiling  Tile. 


and  channels  are  in  use,  and  those  patented  by  Mr.  H.  A.  Streeter, 
of  Chicago,  are  particularly  useful  in  roof  and  suspended-ceiling 
construction,  as  they  do  away  with  all  drilling,  bolting,  etc.,  and 
save  much  time  in  adjusting  T-bars  or  other  shapes  to  different 
widths  of  tiles.* 


*  For  the  safe  loads  which  these  clips  will  carry,  see  Kidder's  "Architect's  and 
Builder's  Pocket-Book,"  Chapter  XXIII. 


FIRE-PROOF  CONSTRUCTION— PARTITIONS,  541 

7,   FIRE-PROOF  PARTITION  CONSTRUCTION. 

466.  GENERAL  CONSIDERATIONS.— The  partitions  con- 
sidered are  those  of  fire-proof  buildings.  They  serve  a  twofold  pur- 
pose :  that  of  dividing  extended  spaces  into  rooms,  and  that  of  pre- 
venting the  spreading  of  a  fire.  They  are  constructed  of  various 
materials,  which,  in  addition  to  fire-resistance,  should  have  the  follow- 
ing properties :  Poor  conductivity  of  heat  and  sound ;  resistance  to 
the  effects  of  water ;  lightness  in  weight. 

A  fire-proof  partition  as  a  whole  should  have  a  rigidity  which 
varies  directly  with  its  length  and  height,  and  also  with  its  particular 
purpose  and  position.  Fire-proofing  considerations  alone  demand  an 
absence  of  all  door  and  window  openings,  and  where  these  conditions: 
obtain,  the  rigidity  should  be  sufficient  to  withstand  the  destructive 
force  of  the  heaviest  streams  of  water  from  the  fire  hose.    But  many 


Type  1  Type  2 

Fig.  400.     Suspended  Ceiling  Under  Roof. 


partitions  require  communicating  doors,  and  others,  such  as  those 
of  dark  corridors,  frequently  have  windows  for  lighting  purposes. 
In  partitions  of  this  latter  type  great  rigidity  is  considered  unneces- 
sary and  even  undesirable  because  of  the  difficulty  of  removing  them 
or  portions  of  them  to  stop  a  spreading  fire. 

The  strength  of  a  partition  to  resist  vertical  loads  need  be  no 
greater  than  that  required  to  sustain  its  own  weight,  unless  it  is  a 
bearing  partition ;  and  very  few  partitions  in  fire-proof  structures 
belong  in  the  latter  class. 

Partition  windows  should  have  stationary  fire-proof  sash,  fire- 
proof frames  and  wire-glass. 

No  materials  should  be  used  in  the  construction  of  partitions  for 
fire-proof  buildings  which  will  not  stand  severe  fire  tests ;  and  the 


542 


BUILDING  CONSTRUCTION.         (Ch.  IX)' 


building  bureaus  of  many  cities  will  not  allow  their  use  if  they 
have  not  thus  satisfactorily  passed  such  required  tests. 

467.  DIFFERENT  TYPES  OF  FIRE-PROOF  PARTI- 
TIONS.— In  a  brief  discussion  of  the  different  kinds  of  partitions 
generally  used  in  fire-proof  and  fire-resisting  buildings,  it  will  be 
convenient  to  group  them  under  several  heads,  according  to  the  type 
of  construction,  the  character  and  purpose  of  the  structure,  and  the 
materials  employed,  as  follows: 

a.  Brick  Partitions. 

b.  Concrete  Partitions. 

1.  Solid  Monolithic  Concrete  Partitions. 

Stone  or  cinder,  with  or  without  reinforcement. 

2.  Concrete  Block  Partitions. 

Stone  or  cinder,  solid  or  hollow  blocks. 
€.  Plaster-block  Partitions. 

d.  Terra-cotta  Partitions. 

e.  Metal-and-plaster  Partitions. 

a.    BRICK  PARTITIONS. 

468.  GENERAL  CONSIDERATIONS.— Experience  proves 
that  hard-burned  common  bricks  make  excellent  fire-resisting  par- 
titions, which  should  be  not  less  than  12  inches  thick.  These  par- 
titions are  used  almost  exclusively  as  bearing  partitions,  as  their 
weight  and  thickness  make  them  inappropriate  for  non-bearing 
purposes. 

b.    CONCRETE  PARTITIONS. 

469.  GENERAL  CONSIDERATIONS.— Partitions  of  con- 
crete may  be  subdivided  as  indicated  in  the  preceding  list  of  the 
different  types.  Compared  with  terra-cotta  or  metal-and-lath,  con- 
crete is  seldom  used,  because  of  its  great  weight,  the  cost  of  the 
wood  forms,  if  monolithic,  and  excessive  thickness  if  not  reinforced 
or  if  in  the  form  of  hollow  blocks. 

Of  the  two  kinds  of  concrete,  that  made  of  cinders  is  the  cheaper 
and  lighter ;  and  cinder  concrete  in  the  form  of  solid  or  hollow 
blocks,  tongued-and-grooved  on  the  edges,  makes  a  partition  mate- 
rial which  passes  the  tests  of  city  building  bureaus.  The  usual 
sizes  of  the  blocks  are,  height,  12  inches;  length,  18  inches ;  thick- 
ness, 2^2  and  3  inches.  The  thinner  blocks  are  solid  and  the  thicker 
ones  hollow. 


FIRE-PROOF  CONSTRUCTION— PARTITIONS.  543 


c.    PLASTER-BLOCK    AND    WALL-BOARD  PARTITIONS. 

470.  GENERAL  DESCRIPTION.— The  materials  composing: 
these  partitions  are  various  patented  combinations  of  plaster  of 
Paris,  chemicals,  reeds,  fibers,  asbestos,  wood  chips,  cinders,  etc., 
and  are  sold  under  different  names.  While  they  make  the  lightest 
partitions,  and  while  they  resist  flame  and  the  transmission  of  heat 
in  an  approved  and  often  in  a  superior  manner,  they  cannot  be 
considered  as  ranking  with  the  best  of  the  fire-proof  materials,  as 
they  do  not  always  come  up  to  the  standards  required  in  the  tests 
of  resistance  to  hose-stream  destruction. 

In  addition  to  their  lightness,  they  have  the  great  advantages  of 
relative  cheapness,  of  being  easily  cut  with  a  saw  and  of 
holding  nails. 

They  are  made  either  solid  or  hollow  and  from  2  to  4  inches  thick, 
those  3  inches  or  more  in  thickness  being  hollow;  and  they  are 
made  with  grooved,  hollowed  or  rebated  edges  so  that  the  mortar 
with  which  they  are  put  together  forms  a  bonding  or  tying  dowel, 
spline  or  key.  Sometimes,  to  further  reinforce  the  partitions  at  the 
block  joints,  horizontal  or  vertical  metal  rods  or  metal  dowels  are 
inserted. 

Plaster-blocks  are  usually  laid  up  in  mortar  composed  of  lime- 
putty,  one  part ;  cement,  two  parts ;  and  sand,  two  or  three  parts, 
although  some  are  laid  in  lime  mortar. 

The  following  are  the  average  weights  per  square  foot  of  plaster 
partition  blocks : 

Thickness  of  blocks,  in  inches  2    2^  3       3]^  4568 

Weight  in  pounds  per  square  ^foot ..  7    8>4         10^  12  15  18  22 

Plaster-boards  average  i  inch  in  thickness  and  4  pounds  per 
square  foot  in  weight. 

To  obtain  the  weight  of  a  partition  plastered  on  both  sides 
there  must  be  added  to  the  weight  of  the  partition  as  given  above 
about  18  pounds  per  square  foot. 

Scaglioline  Partition  Blocks."^ — These  blocks  are  made  of  plaster 
of  Paris,  chemicals  and  well-burned  cinders,  and  are  furnished  in 
sizes  of  18  by  24  inches,  2,  3  or  4  inches  thick.  The  approximate 
weight  of  a  3-inch  block  is  12  pounds  per  square  foot. 

Fig.  401  shows  the  general  form  of  one  of  these  blocks,  and  Fig. 


*  Manufactured  and  patented  by  the  Fire-proof  Partition  Company,  i  Madison  Ave., 
New  York. 


Fig.  402.    Ellendt  Reinforced  Block  Partition. 


FIRE-PROOF  CONSTRUCTION— PARTITIONS.  545 


.402  shows  the  most  recent  improved  method  of  constructing  them 
•and  building  them  into  a  rigid  and  Hght  partition  wall  by  the  use  of 
light  continuous  reinforcing  rods  or  wires  running  horizontally  and 
vertically  as  shown.  This  construction  is  known  as  the  *'Ellendt 
Reinforced  Block  Partition." 

Gypsite  Partitions  * — The  materials  used  are  mainly  pure  gypsum 
and  a  specially  prepared  strong  and  tough  interlacing  fiber.  Two 
systems  of  partition  construction  are  used — the  *'tile  construction" 
and  the  ''solid-  construction."  In  the  former,  gypsite  tiles,  i  inch' 
thick  and  in  two  thicknesses,  separated,  are  securely  bonded  by 
means  of  stalf  uprights  12  inches  on  centers,  cast  in  place  between 
the  inner  faces  of  the  tiles.  In  the  latter  the  partition  is  con- 
structed by  pouring  the  material  in  liquid  form  about  a  framework 
of  channel-iron  verticals  with  wood  nailing-blocks  wired  thereto, 
the  metal  and  wood  being  completely  imbedded  in  staff. 

Mackolite  Partition  Tile.^ — The  basis  of  mackolite,  an  inven- 
tion of  Messrs.  A.  and  O.  Mack,  of  Ludwigsburg,  Germany,  is 
gypsum,  which  is  calcined,  ground,  mixed  with  certain  chemicals, 
reeds  and  fibers,  and  then  poured  into  molds,  left  for  about  one- 
half  hour  to  set,  and  then  kiln-dried  for  four  days.  The  thicknesses 
of  the  blocks  or  tiles  are  3,  3^2,  4,  6,  8  and  12  inches;  the  height 
of  all,  12  inches;  and  the  length,  48  inches  for  the  3-,  3^-  arid 
.4-inch  blocks,  and  30  inches  for  the  others.  Fig.  403  shows  the 
general  shape  of  these  mackolite  hollow  blocks.  They  are  made 
also  with  "grooved  edges.  They  are  laid  to  break  joints  in  courses 
as  shown  in  Fig.  404,  and  are  fitted  around  openings  and  angles 
by  being  cut  with  a  saw. 

''U.  S.  G."  Fibered  Plaster  Partition  Blocks. X — These  blocks  are 
made  of  a  high  grade  of  plaster  of  Paris,  combined  with  cocoanut 
fiber  for  toughness,  and  are  either  solid  or  hollow,  in  standard  units 
of  varying  thickness  for  different  purposes.  They  have  been  used 
for  partitions  in  some  recent  important  fire-proof  buildings,  and  are 
very  light  in  weight,  easy  to  put  up,  resistant  to  the  passage  of 
sound,  and  easily  cut  with  a  saw  or  nailed  into. 

Gypsinite  Partitions.^ — Although  these  partitions  are  not  strictly 
plaster-^'block"  partitions,  they  may  be  mentioned  here  conveniently. 

*  Manufactured  and  patented  by  the  Detroit  Fire-proofing  Tile  Company,  Pittsburg,  Pa. 
t  Manufactured  and  patented  by  the  Mackolite  Fire-proofing  Company,  Chicago,  III. 
t  Manufactured  and  patented  by  the  United  States  Gypsum  Company,  New  York. 
§  Manufactured  and  patented  by  the  Gypsinite  Company,  New  York. 


546  BUILDING  CONSTRUCTION.         (Ch.  IX) 

The  partitions  consist  of  studs  made  of  wood  strips  imbedded  in 
and  protected  by  the  gypsinite  which  is  a  plaster  composition.  These 
gypsmite  studs  are  usually  set  i6  inches  on  centers,  bridged  similarly 
to  wood  studding  and  covered  with  plaster-boards  and  plaster  or 
with  metal  lath  and  plaster,  as  shown  in  Fig.  405.  They  are 
secured  to  floor  and  ceiling  either  by  channel-irons  or  by  gypsinite 


Stowing  2  in.,  3  in.,  4  in.,  5  in.  and  6  in.  Hollow  Mackolite  partition 
tile  30  inches  long. 

Fig.  403.    Mackolite  Hollow  Partition  Blocks. 


Sills  and  plates  nailed  to  the  fire-proofing.  The  average  total  thick- 
ness of  the  partition  is  about  4^^  inches,  the  stock  sizes  of  the 
studding  3  by  3  inches  by  12  feet,  and  the  weight  of  studs  3  pounds 
to  the  foot. 

The  principal  advantages  claimed  for  these  partitions  are  their 
sound-proof  property,  their  stiffness  and  strength,  their  light  weight, 


FIRE-PROOF  CONSTRUCTION— PARTITIONS.  547 


their  adaptation  to  the  passage  of  pipes,  low  cost  and  nail-holding 
properties. 

There  are  other  excellent  partition  plaster-blocks  besides  those 
already  mentioned,  but  it  is  not  possible  to  refer  to  them  all. 

Sackett's  Wall-Board  or  Plaster-Board.'^ — This  is  made  in  32  by 
36-inch  sheets  about  34  of  a"  inch  thick,  of  alternate  layers  of 
strong  wool  felt  and  plaster,  and  is  nailed  directly  to'  the  studding, 


Fig.   405.    Gypsinite  Partition. 


which  is  set  16  inches  on  centers.  For  cutting  and  fitting  an  ordi- 
nary saw  is  used;  and  for  nailing,  134-inch  wire  nails  with  large 
heads,  set  from  4  to  6  inches  apart,  each  nail  being  driven  home 
firmly  and  tightly  to  prevent  any  working  under  the  plaster  coat. 
The  boards  are  spaced  34  of  an  inch  apart,  breaking  joint  horizon- 
tally on  the  walls  and  at  right-angles  to  the  furring  on  the  ceiling. 

The  best  plastering  results  are  obtained  by  first  thoroughly  filling 
the  joints  between  the  boards  and  then  applying  a  brown  coat,  from 
^  to  ^  of  an  inch  thick,  of  any  good  brand  of  hard  wall  plaster. 
When  the  first  coat  is  thoroughly  set,  it  is  finished  with  a  thin  coat 
of  regular  hard  finish,  lime  putty  and  plaster,  or  a  patent  ready 
finish. 


*  Manufactured  and  patented  by  the  Sackett  Wall  Board  Company,  New  York. 


548 


BUILDING  CONSTRUCTION.  (Ch.  IXy 


This  plaster-board  has  been  widely  used  in  many  important 
buildings,  and  the  principal  advantages  claimed  for  it  are  its  free- 
dom from-  shrinking,  warping  and  buckling;  its  fire-resistance;  its 
lightness ;  the  reduction  in  the  amount  of  w^ater  used  in  plastering 
on  account  of  the  smaller  amount  of  plaster  needed ;  and  its  lower 
cost  for  the  same  reason,  when  compared  with  metal  lath. 

Plaster-boards  are  made  also  of  greater  thickness  than  the  above- 
mentioned  Sackett's  boards,  the  thickness  running  from  ^  of  an 
inch  to  2  inches. 

d.    TERRA-COTTA  PARTITIONS. 

471.  GENERAL  DESCRIPTION.— In  addition  to  the  fire- 
resisting  qualities  of  terra-cotta  partitions,  they  are  lighter  than 
those  of  brick  or  concrete,  strong,  easily  erected  by  bricklayers, 
and  do  not  transmit  heat,  cold  or  sound  to  any  great  extent. 

About  15  per  cent  of  the  quantity  of  blocks  required  should  be 
of  full  porous  material  for  the  nailing  of  the  wood  trim.  In  school- 
houses,  where  blackboards  have  to  be  fastened  on  the  walls,  all  of 
the  blocks  should  be  full  porous.  These  are  slightly  more  expen- 
sive, but  make  a  better  partition  for  any  purpose.  All  partitions  and 
furring  blocks,  unless  otherwise  specified,  are  scratched  to  receive 
plastering.  If  the  surface  is  to  be  whitewashed  the  blocks  are  made 
smooth. 

Wood  or  channel-iron  bucks  are  placed  in  all  doorway  openings. 
These  should  be  inches  wider  than  the  thickness  of  the  blocks, 
as  they  act  as  grounds  for  the  plastering. 

It  is  not  generally  practicable  to  use  2-inch  blocks  for  partitions, 
except  for  closets,  shafts,  etc.,  unless  they  are  reinforced  by  metal. 
Where  room  must  be  economized  the  "New  York"  reinforced  par- 
tition may  be  employed,  using  2-inch  partition  blocks  with  the  truss 
wire  in  the  horizontal  joints.  This  is  the  Bevier  patent,  and  made 
iby  the  National  Fire-proofing  Company,  Pittsburg,  Pa.  See 
Fig.  409. 

Three-inch  partition  blocks  can  be  safely  used  up  to  12-feet, 
4-inch  to  14-feet,  and  6-inch  to  20-feet  heights. 

The  blocks  are  commonly  made  12  inches  high  by  12  inches  long, 
although  some  prefer  to  have  them  8  inches  high.  They  may  be 
brick-shape  also.  They  can  be  made  any  size  required,  but  special 
sizes  are  necessarily  more  expensive. 


FIRE-PROOF  CONSTRUCTION— PARTITIONS.  549 

In  office-buildings  it  is  good  practice  to  have  all  the  main  corridor, 
stairway  and  elevator  enclosures  of  4-inch  and  the  partitions  be- 
tween rooms  of  3-inch  blocks.  Partitions  should  be  bonded  where 
meeting  and  anchored  to  wood  bucks  or  brick  walls  by  using  ten- 
penny  nails  in  at  least  every  second  joint. 


Fig.  406.    Terra-cotta  Partition  Blocks. 


When  required  for  outside  walls  exposed  to  the  weather,  the 
blocks  should  be  of  specially  made  dense,  hard-burned  material. 
These  are  made  smooth  on  the  outside  face  and  do  not  require 
plastering.  They  should  not  be  less  than  6  inches  thick  unless 
reinforced. 

Fig.  406  shows  some  terra-cotta  partition  blocks  in  typical  shapes. 


550  BUILDING  CONSTRUCTION.         (Ch.  IX) 

the  four  figures  on  the  right  side  of  the  drawing  being  the  brick- 
shaped  blocks.  The  voids  are  usually  in  a  horizontal  position  in  a 
partition,  and  the  pieces  are  set  to  break  joints  horizontally. 

The  mortar  generally  used  is  made  of  lime-putty,  one  part; 
cement,  two  parts ;  and  sand,  two  or  three  parts. 

Fig.  407  shows  partition  blocks  with  circular  and  angular  corners, 
in  which  the. voids  are  in  a  vertical  position  in  the  wall. 

Fig.  408  shows  a  2-inch  'Thoenix"  partition  made  of  terra-cotta 
blocks  reinforced  with  light  band-iron,  manufactured  by  Henry 
Maurer  &  Son,  New  York,  and  patented.  The  iron  greatly  increases 
the  rigidity  of  the  partition.  It  is  hardly  practicable  to  use  2-inch 
terra-cotta  partitions  unless  they  are  fortified  or  reinforced  in  some 
such  way  as  this. 

Fig.  409  shows  the  general  form  of  the  ''New  York"  partition, 
Bevier  patent,  with  the  wire  truss  reinforcement. 

The  weights  of  porous,  semi-porous  and  dense  terra-cotta  par- 
titions vary  as  follows : 

2-  inch  partition,  10  to  14  pounds  per  square  foot; 

3-  inch  partition,  12  to  16  pounds  per  square  foot; 

4-  inch  partition,  13  to  19  pounds  per  square  foot; 

5-  inch  partition,  20  to  22  pounds  per  square  foot ; 

6-  inch  partition,  22  to  23  pounds  per  square  foot ; 
8-inch  partition,  28  to  33  pounds  per  square  foot. 

Ten  pounds  per  square  foot  must  be  added  to  these  weights,  if 
plastering  on  both  sides  is  to  be  included. 

e.    METAL-AND  PLASTER  PARTITIONS. 

472.  GENERAL  DESCRIPTION.— These  partitions  consist  of 
some  form  of  metal  lath,  generally  with,  but  sometimes  without, 
metal  studding,  plastered  on  both  sides,  solid  or  hollow  and  with 
or  without  a  cinder  concrete  core.  Those  with  metal  studs,  made 
solid  and  finishing  about  2  inches  thick,  have  been  the  most  exten- 
sively used. 

The  advantages  are :  good  resistance  to  the  passage  of  fire ;  sav- 
ing of  room ;  great  stififness ;  and  very  light  weight  in  proportion  to 
strength. 

The  disadvantages  are :  strong  tendency  for  the  plaster  to  be 
washed  off  by  the  water  from  the  fire  hose  and  for  the  lath  to 
become  exposed ;  tendency  for  the  lath,  even  when  painted,  to  be 
injured  by  corrosive  properties  of  the  plaster;  and  objections  on 


FIRE-PROOF  CONSTRUCTION— PARTITIONS.  551 


552 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


the  part  of  fire  underwriters  to  too  great  resistance  of  the  lath  to 
any  necessary  cutting  through  in  case  of  fire. 

In  estimating  the  weights  of  metal-and-plaster  partitions,  it  is 
usual  to  allow  120  pounds  per  cubic  foot  for  plaster  and  96  pounds 
per  cubic  foot  for  lightly  tamped  cinder  concrete;  but  the  average 
solid  2-inch  partition,  dried  out,  may  be  conveniently  figured 
directly  at  about  20  pounds  per  square  foot. 

There  are  two  general  types  of  metal-and-plaster  fire-proof  par- 
titions: (i)  the  ''Single"  Solid  Partition  and  (2)  the  ''Double"  Par- 
tition, which  may  be  solid  or  hollow.  Their  construction  is  briefly 
described  in  the  following  articles. 

473.  GENERAL  CONSTRUCTION  OF  "SINGLE"  SOLID 
METAL-AND-PLASTER  PARTITIONS.— Fig.  410  shows  an 
elevation  and  two  sections  of  a  typical  "single"  solid  metal-and- 
plaster  partition,  the  one  shown  being  a  2-inch  partition,  together 
with  section  of  typical  wood  trim.  The  following  are  the  principal 
construction  data:  Studs  usually  J^-  or  i-inch  channel-irons  or 
other  convenient  sections,  placed  12  inches  on  centers  for  heights 
over  10  feet,  and  16  inches  for  heights  under  10  feet;  studs  f*as- 
tened  at  lower  ends  by  bending  and  punching  the  latter  and  by  nail- 
ing them  to  strips  of  wood  fastened  to  the  floor  beams  or  fire- 
proofing,  said  strips  being  used  as  a  more  resisting  material  in  allow- 
ing for  the  expansion  caused  by  fire;  studs  fastened  at  upper  ends 
by  nailing  them  to  the  fire-proofing  or  by  wiring  them  to  the  ceil- 
ing metal;  framing  of  openings  usually  i  by  i  by  3/16-inch  angle- 
irons,  to  which  are  fastened  the  rough  wooden  frames,  with  No.  12 
screws  through  holes  bored  16  inches  on  centers;  metal-lathirf^  of 
appropriate  kind  and  weight  secured  to  one  side  of  studs  with  No. 
18  galvanized-wire  lacing  at  the  crossings  of  ^-inch  steel  stiffening 
rods  placed  horizontally  about  73^  inches  on  centers;  wood  grounds 
put  on  where  required,  by  fastening  them  with  staples  to  the  studs ; 
five  coats  of  some  approved  hard-setting  wall-plaster  put  on  the 
metal-lathing,  including  one  scratch  coat  on  one  side,  one  brown 
coat  on  both  sides  and  one  white  coat  on  both  sides ;  a  finished 
trim  of  wood  or  other  material  nailed  or  otherwise  fastened  to  the 
rough  frame. 

474.  GENERAL  CONSTRUCTION  OF  "DOUBLE" 
METAL  AND  PLASTER  PARTITIONS.— In  this  classification 
a  "double"  partition  means  one  in  which  the  metal  lath  is  fastened 


FIRE-PROOF  CONSTRUCTION— PARTITIONS.  553 


'A'6t€el  Rod    /  FuRRtNG  for  Baseboard  r^/ ^ 


Enlarged  Section  on  A  A 


Typical  Section  of  Wood  Trim. 

Fig.  410     Single  Solid  Wire-lath  Partition. 


554 


BUILDING  CONSTRUCTION. 


(Ch.  ixy 


on  both  sides  of  the  metal  studs.  These  partitions  may  be  either 
soHd  or  hollow.  Only  electric  wires  and  pipes  of  not  much  over  ^- 
inch  diameter  can  be  run  in  2-inch  solid  partitions,  and  thicker  ones 
must  consequently  be  built  if  they  are  to  conceal  larger  pipes.  In 


'A/2  J8  G/TL.  yy//?£  L/JC/NG  '        x£  "x  '/3  "'L 

Fig,  411a.    Double  Solid  Wire-lath  Partition. 


Typrcal  Section  of  Wood  Trim. 

Fig.  411b.    Double  Solid  Wire-lath  Partition. 


^ 


,  NX*.  ''M'SteehFIod 
V  Air  5 pace 


Fig.  412.    Double  Hollow  Wire-lath  Partition. 


this  latter  case  rolled  or  sheet-steel  channels,  2-,  3-  or  4-inch,  are 
used. 

In  double  solid  partitions  the  inside  space  between  the  two 
layers  of  metal  lath  is  often  filled  in  with  cinder  concrete,  into  which 


FIRE-PROOF  CONSTRUCTION— PARTITIONS.  555 


nails  can  be  driven,  thus  doing  away  with  the  necessity  of  wood 
furring. 

Figs.  411a  and  h  show  horizontal  sections  through  such  double 
solid  partitions,  finishing,  when  plastered,  4  inches  thick.  A  typical 
construction  for  a  door  trim  is  shown  also.  A  partition  of  this 
kind  has  great  fire-resistance  and  strength. 

Fig.  412  shows  the  construction  of  a  double  hollow  4-inch  par- 
tition. In  this  type  an  air-space  is  left,  no  core  or  mortar  or  concrete 
being  put  between  the  studding  and  lathing.  The  cost  is  greater 
than  that  of  a  single  solid  partition  of  less  thickness,  and  the  fire- 
resistance  is  not  so  good. 

The  spacing  of  2-inch  studs  in  hollow  partitions  is  usually  12 
inches  on  centers  for  heights  of  16  feet  or  more  and  16  inches  for 
heights  less  than  16  feet. 

475.  THE  BERGER  PRONG-LOCK  STUDS  FOR  METAL- 
AND-PLASTER  PARTITIONS.— G^^i^ra/  Description.— ¥\g.  413 
shows  a  form  of  studding  made  and  patented  by  the  Berger  Man- 
ufacturing Company,  of  Canton,  Ohio,  and  known  as  the  "Berger 
Prong  Lock  Wireless  System  of  Steel  Studding  for  Fire-proof 
Walls  and  Partitions."  It  is  used  also  for  furring  walls,  ceilings, 
•€tc. 

It  is  made  in  various  sizes,  from  No.  20,  No.  18  or  No.  16  gauge 
sheet-steel,  and  in  several  different  shapes,  such  as  channels,  T's, 
L's,  U's  and  Z's,  with  necessary  fastenings  for  the  top  and  bottom. 

The  marked  advantages  possessed  by  these  studs  and  furring 
strips  is  the  provision  for  attaching  the  metal  lath.  For  this  pur- 
pose prongs  are  punched  out  on  the  face  of  the  studs  and  stand  at 
right-angles  to  the  faces  from  which  they  are  punched,  ready  to 
receive  the  lath.  In  applying  the  latter  these  prongs  pass  through 
the  meshes  and  are  clinched  over  them  with  a  hammer,  thus  hold- 
ing the  lath  firmly  and  securely  and  leaving  a  true  surface  for  the 
plasterer  to  work  on.  Angle-irons  may  be  used  for  turning  all  cor- 
ners. The  "Z"-strip,  *'U"-strip,  "L"-strip  or  a  special  furring  strip 
may  be  used  for  suspended  ceilings  or  for  ceilings  applied  directly 
to  the  under  side  of  the  floor  beams  with  specially  designed  clips. 
Similar  members  are  manufactured  for  light  structures  of  all  kinds. 

Spacing  of  Studding. — For  2-inch  solid  partitions  with  ^-inch 
rolled  channels  or  i-inch  Prong-lock  Studs,  the  channels  or  studs 
should  be  placed  12  inches  on  centers  when  the  height  of  a  story 


556 


BUILDING  CONSTRUCTION. 


(Ch.  IX)* 


B 


exceeds  lo  feet.  When  the  height  of  a  story  is  less  than  lo  feet,, 
a  spacing  of  i6  inches  will  answer.  For  hollow  partitions  with 
2-inch  studs  the  latter  can  be  spaced  i6  inches  on  centers  for  story 

heights  of  i6  inches  and  less.  For 
greater  heights  they  should  be  placed 
12  inches  on  centers. 

Weight. — The  weight  of  a  2-inch  solid 
partition  is  about  20  pounds  per  square 
foot,  when  dry.  The  weight  of  parti- 
tions of  greater  thickness  may  be  esti- 
mated on  a  basis  of  120  pounds  per  cubic 
foot  for  plaster  and  96  pounds  for  cinder 
concrete,  slightly  tamped. 

Cost. — The  cost  of  2-inch  solid  parti- 
tions ranges  from  16  to  20  cents  per 
square  foot,  including  plaster. 

476.    RIB-STUDS    FOR  METAL- 
AND-PLASTER  PARTITIONS.— Fig. 
414  shows  a  form  of  studding  made  and 
patented  by  the  Trussed  Concrete  Steel 
Company,  of  Detroit,  Mich.,  and  called 
"Rib-studs ;"  and  shows  also  the  applica- 
tion of  such  studs   and  of  "Rib-lath," 
which  is  made  on  the  same  principle,  to 
hollow  partitions,  in  this  example  in  con- 
nection with  hollow  tiles  and  the  Kahn 
system   of    i-einforced    concrete  floors. 
These  studs  consist  of  a  series  of  straight 
ribs,  or  main  tension  members,  connected 
by  light  cross  ties  which  act  as  spacers,  provide  a  mechanical  bond 
and  resist  shrinkage  and  temperature  stresses.     The  method  of 
fastening  them  in  place  is  shown  in  the  figure.    They  are  made  in 
lYe-,  2}i-,  3^-  and  4^ -inch  widths,  and  also  in  additional  widths, 
if  required,  up  to  8}^  inches.    They  can  be  made  in  any  length  up 
to  20  feet. 

477.  ALLUNITED  STEEL  STUDDING  FOR  METAL-AND- 
PLASTER  PARTITIONS.— Fig.  415  shows  a  form  of  studding 
made  and  patented  by  the  General  Fire-proofing  Company,  of 
Youngstown,  Ohio,  and  called  the  "Allunited  Steel  Studding."  The 


Fig. 


413.      Berger  Prong-lock 
Stud  and  Fastenings 


FIRE-PROOF  CONSTRUCTION— PARrrnONS.  557 

studs  are  made  with  side  slots  for  solid  partitions,  and  with  middle 
slots,  as  shown,  for  double-lathed  partitions,  and  are  secured  in  place 
at  top  and  bottom  by  bending  and  nailing.  The  pieces  are  rivetted 
together,  holes  being  left  in  the  horizontal  braces  for  spacing  studs 


Fig.  414.    Rib-studs  for  Partitions, 


either  12  or  16  inches  on  centers.  Fig.  416  shows  the  manner  of 
holding  wood  blocks  for  grounds  for  base,  chair-rail,  picture-mold, 
etc.,  or  for  plaster  grounds  to  insure  proper  thickness  of  the  plas- 
tered wall.  For  solid  partitions  these  studs  are  made  in  widths  of 
I  and  1^4  inches;  for  double-lathed  hollow  partitions,  in  widths 


'558 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


Df  2,  2^4,  3  and  y/2  inches.  No.  i6-gauge  steel  is  used,  and 
the  weights  vary  from        to  7  pounds  per  square  yard. 

478.  METAL-AND-PLASTER  PARTITIONS  WITHOUT 
STUDDING. — There  are  several  types  of  metal-and-plaster  par- 
titions which  can  be  put  up  without  the  use  of  studs. 

Figs.  417  and  418  show  two  varieties  of  one  type  of  soHd  stud- 
ess  metal-and-plaster  fire-proof  partitions,  in  which  the  "Tri- 
angular Mesh  Steel  Fabrics,"  made  by  the  American  Steel  and  Wire 
Company,  of  Chicago,  are  used.    In  the  6-inch  partition  indicated  in 


Fig.   415.    Allunited   Steel   Studding.  Fig.  416.     Allunited  Steel  Studding 

and  Grounds. 


Fig.  417  the  triangular  mesh  fabric  is  placed  in  a  vertical  position 
in  a  rectangular-fret  form^  the  method  of  weaving  the  longitudinal 
and  cross  wires  being  such  as  to  allow  this  position.  The  result  of 
the  finished  construction  is  a  very  good  solid  stifif  partition.  Fig. 
418  shows  a  different  arrangement  of  the  fabric,  zigzag  in  plan,  for 
thinner  partitions,  the  illustration  being  for  a  3-inch  thickness.  The 
materials  used  for  plastering  may  be  any  of  the  approved  plaster- 
ing compositions,  or  stone  or  cinder  concretes. 

Fig.  419  shows  the  "Truss  Metal  Lath,"  Kiihne  patent,  manu- 
factured by  the  Truss  Metal  Lath  Company,  of  New  York,  and 
tised  in  the  construction  of  solid  strong  and  very  rigid  partitions, 
one  form  of  which  is  shown  in  Fig.  420.    It  belongs  to  the  class  of 


FIRE-PROOF  CONSTRUCTION— PARTITIONS.  559 


expanded-metal  laths,  and  is  very  highly  recommended  in  the  matter 
of  taking  and  holding  mortar,  and  of  resistance  to  fire  and  to  hose 
streams.  It  is  made  from  soft  steel,  of  Nos.  24,  26  and  28  gauges, 
in  sheets  varying  in  width  up  to  30  inches,   in   length   up   to  9 

^ — Triangular  Meih  Relnforcemant  plaoed'verfletiilly 

Fig.  417.    Triangular  Mesh  Fabric.     Six-inch  Partition. 

feet  4  inches,  and  with  a  thickness  of  about  i  inch.  It  may  be 
obtained  either  black  or  galvanized.  Fig.  420  shows  sections  through 
a  "Truss  Metal  Lath''  partition  and  through  jamb  and  head-casing 
of  door,  with  the  lath  secured  to  a  flat  iron  frame  of  the  same  width 
as  the  finished  partition.    To  this  iron  frame  a  smaller  flat  iron  is. 


Vote  hinge  joint  on  each  longitudinal  ualaber 


Fig.  418.     Triangular  Mesh  Fabric.  Three-incli  Partition. 


bolted,  with  pipe  separators,  to  which  the  lath  is  fastened,  allowing^ 
the  plaster  or  concrete  to  surround  the  iron.  The  wood  trim  is. 
secured  in  place  as  shown. 


Fig.  419.     Truss  Metal  Lath. 


Fig.  421  shows  another  form  of  metal-and-plaster  solid  parti- 
tion in  which  the  "Ferroinclave"  thin  steel  corrugated  sheets, 
made  by  the  Brown  Hoisting  Machinery  Company,  of  Cleveland, 
Ohio,  are  used. 

479.  DIFFERENT  KINDS  OF  METAL  LATH  FOR  PLAS- 
TERED  PARTITIONS.— The  many  varieties  of  metal  lath  manu-- 


56o 


BUILDING  CONSTRUCTION. 


(Ch.  ixy 


Fig.  421.     Ferroinclave  Partition. 


FIRE-PROOF  CONSTRUCTION— METAL  LATH.  561 


factured  to  suit  different  constructive  necessities  and  plastering 
requirements  may  be  conveniently  classified  as  follows : 

1.  Wire  Lath. 

(1)  Unstiffened  or ''plain." 

(2)  Stiffened. 

a.  With  corrugated  steel  furring  strips. 

b.  With  round  rods. 

c.  With  V-shaped  stiffening  ribs. 

2.  Expanded-metal  Lath. 

(1)  a.  "A"  and  "B"  Lath. 

.  h.  Diamond  Mesh  Lath. 

(2)  Herringbone  Lath. 

(3)  Imperial  or  Spiral  Lath. 

3.  Perforated  Sheet-metal  lath. 

(1)  Bostwick  Steel  Lath. 

(2)  Kiihne's  Clincher  Lath. 

(3)  Rib  Lath. 

(4)  Miscellaneous  forms. 

4.  Other  forms  already  mentioned,  such  as 

(1)  Welded  Fabric  or  Mesh. 

(2)  Lock- woven  Fabric. 

(3)  Steel  Wire  Fabric. 

a.  Triangular  Mesh. 

b.  Square  Mesh. 

(4)  Miscellaneous  forms. 

480.  I.  WIRE  LATH  OR  WIRE  CLOTH.— Regarding  ?/7i.y/«y- 
jened  or  ''plain"  wire  lath  or  wire  cloth  the  following  are  the  prin- 
cipal facts:  Wire  commonly  used,  No.  17  to  No.  20  gauge;  number 
of  meshes,  generally  2^/^  by  2^  to  the  square  inch ;  usual  widths,  32 
and  36  inches,  some  manufacturers,  however,  furnishing  it  in  any 
w^idth  up  to  8  feet ;  finish  of  lath,  unpainted  or  ''bright,"  painted  or 
galvanized,  the  last  two  being  used  with  patented  hard-plaster  com- 
positions ;  stiffness  greatly  increased  by  galvanizing,  the  wires  being 
zinc-soldered  together  at  their  intersections  ;  tendency  to  corrosion 
before  plastering  lessened  by  galvanizing;  all  wire  lathing  tightly 
stretched  to  give  tight,  stiff  surface  for  plaster. 

Data  for  stiffened  wire  lath : 

In  all  varieties  the  stiffeners  run  at  right-angles  to  the  bearings. 
The  best-known  wire  laths  are  the  "Clinton"  and  the  "Roebling." 


562  BUILDING  CONSTRUCTION.  (Ch.  IX> 

The  Clinton  stiffened  wire  lath  is  made  from  i8-  to  22-gauge 
wire,  either  japanned  or  galvanized,  in  100-yard  rolls,  in  32-  or 
36-inch  widths,  and  is  stiffened  either  with  corrugated  steel  furring 
strips  fastened  with  metal  clips  crosswise  about  every  8  inches,  or 
with  round  rods,  varying  in  diameter  from  ^  to  ^4  of  ^^'^  i^^ch  and 
in  spacing  on  centers  from  8  to  12  inches.  With  the  corrugated 
stiffeners  no  other  furring  strips  are  needed. 

The  Roebling  standard  stiffened  wire  lath  is  made  of  No.  20 
plain  wire  cloth,  generally  painted,  but  furnished  also  bright  or  gal- 
vanized, in  36-inch  widths  for  beams  or  studs  spaced  12  inches  on 
centers  and  in  32-  or  48-inch  widths  for  16-inch  spacing.  The 
proper  widths  should  always  be  ascertained  before  ordering.  The 
stiffening  is  accomplished  by  means  of  V-shaped  ribs  made  of  No. 
24  sheet-steel,  either  or  i  inch  deep  and  woven  in,  about  7^ 
inches  on  centers.  The  wire  lath  with  the  i^-inch  ribs  is  used  on 
woodwork,  no  furring  being  necessary  and  the  lath  being  fastened 
by  driving  steel  nails  through  the  angle  of  the  V's ;  and  the  lath 
with  the  I -inch  rib  is  used  as  a  combined  furring  and  lathing,  on 
exterior  walls,  for  example,  an  air-space  being  thus  provided  between 
the  plaster  and  the  wall.  The  Roebling  Construction  Company  make 
also  a  metal  lath  called  the  "solid-rib  stiffened  wire  lath,"  in  which 
the  V-ribs  are  replaced  by  3/16-  or  ^-inch  solid  steel  rods,  and  which 
is  used  when  required  to  be  applied  to  light  metal  furring.  It  is  fas- 
tened to  the  latter  by  lacing  wire.  Both  the  plain  and  stiffened 
Roebling  wire  laths  are  made  with  2^  by  25^  meshes  to  the  square 
inch  for  ordinary  lime-and-hair  plaster,  and  with  3  by  3  and  2^  by 
4  meshes  for  hard  wall  plasters  and  for  thin  partitions.  The  2^ 
by  4-mesh  lath  is  known  commonly  as  "close-warp"  lath. 

Fig.  422  shows  the  unstiffened  and  Fig.  423  the  stiffened  Clinton 
wire  lath. 

Fig.  424  shows  the  Roebling  No.  18  wire  2  by  2  and  2j/^  by  2^- 
mesh  and  the  No.  20  wire  2^  by  4-mesh  wire  lath. 

Fig.  425  shows  the  Roebling  Standard  stiffened  wire  lath,  the 
plaster  applied  to  part  of  it  and  the  manner  in  which  nails  are  driven 
through  the  V-ribs  to  secure  the  lath  in  place. 

481.  2.  EXPANDED-METAL  LATH.— This  material,  con- 
trolled by  the  Associated  Expanded  Metal  Companies,  and  with 
offices  under  various  names  in  the  principal  cities,  has  been  used 
very  extensively  both  for  lathing  on  wood  construction  and  for 


FIRE-PROOF  CONSTRUCTION— METAL  LATH.  563 


^^^^ 

1'  7  »  f  1 

1 — 

■ 

f 

•     1  f 

j  1  r  I  I 

\  — 

,  i 

'            t  t 

t 

_/!  !  ' 

Fig.  422.     Clinton  Wire  Lath,  Plain, 


Fig;  423.    Clinton  Wive  Lath,  V-stiffened. 


2)^x4  Mesh,  No  20. 

Fig.    424.     Roebling  Wire 
Lath,  Plain. 


564 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


fire-proof  work.  It  is  made  from  strips  of  thin,  soft  and  tough 
steel  by  a  mechanical  process  which  pushes  out  or  expands  the 
metal  into  oblong  meshes,  and  at  the  same  time  reverses  the  direc- 
tion of  the  edges,  so  that  the  flat  surface  of  a  cut  strand  is  nearly 
at  right-angles  with  the  general  surface  of  the  sheet.  The  lath  ' 
being  flat  and  of  considerable  stiffness,  does  not  require  to  be 
stretched,  and  can  be  fastened  directly  to  the  under  side  of  floor 
joists  or  to  wood  studding.  If  used  on  planks  it  should  be  fastened 
over  metal  furring  strips.  When  applied  to  studding  the  lath 
should  be  placed  so  that  the  long  way  of  the  mesh  will  be  at  right- 
angles  to  the  studding,  as  this  insures  the  greatest  rigidity.  The 
studding  or  furring  strips  should  be  spaced  12  or  16  inches  on 
centers,  and  the  lathing  secured  with  staples  i  inch  long,  driven 
about  5  inches  apart  on  the  studs  or  joists.    The  lath,  when  applied, 


Fig.  426.     "A"   and  "B"   Expanded-metal       Fig.  427.    Diamond  Expanded-metal  Lath. 
Lath. 

is  a  scant  ^  of  an  inch  in  thickness,  and  to  obtain  a  good  wall 
3/ -inch  grounds  should  be  used. 

There  are  two  varieties  of  the  first  of  the  three  classes  of 
expanded-metal  lath  used  for  plastering  and  mentioned  in  the  classi- 
fication, both  being  made  in  sheets  8  feet  long  and  from  i8  to  24 
inches  wide.  Fig.  426  shows  the  ''A"  and  ''B"  expanded-metal 
lath,  usually  of  0.6  by  1.5  inches  mesh  and  24  and  27  Stubbs' 
gauge;  and  Fig.  427  shows  the  ''Diamond  Mesh"  expanded-metal 
lath,  usually  of  0.41  by  1.2  inches  mesh  and  24  and  26  Stubbs'  gauge. 

The  ''Herringbone"  expanded-metal  lath  is  a  later  improved  form, 
made  in  four  varieties  or  grades,  known  respectively  as  *'AA,"  ''A," 
''BB"  and  ''B."  The  AA  grade  is  the  stififest  and  can  be  used  on 
studding  spaced  16  inches  on  centers.  It  is  the  most  expensive  of 
the  four  grades.    The  A  grade  has  a  larger  mesh  and  is  not  as  stifip 


FIRE-PROOF  CONSTRUCTION— METAL  LATH.  565 


as  the  A  A  grade.  It  is  better  to  have  the  studding  spaced  12  inches 
on  centers,  although  16-inch  spacing  can  be  used.  It  is  the  grade 
most  used.  These  two  grades  are  the  ones  used  for  lathing  ceil- 
ings, and  should  be  specified  as  ''AA  flat"  or  "A  flat,"  which  means 
that  the  short  cross  ribs  are  turned  after  being  ''expanded,"  thus 
diminishing  the  size  of  the  key  and  offering  a  larger  surface  for 
supporting  the  plaster. 

The  BB  and  B  grades  are  made  in  wider  sheets,  are  more  open, 
and  are  not  as  heavy  nor  as  stiff  as  the  AA  and  A  grades.  Both, 
as  in  the  case  of  the  A  grade,  should  have  the  studs  set  12  inches  on 
centers.  The  B  grade  has  a  larger  mesh  and  is  not  as  stiff  as  the 
BB  grade. 

Fig.  428  shows  the  general  forms  of  grades  BB  and  A  of  the 
herringbone  expanded-steel  lath,  and  Fig.  429  shows  a  fire-proof 


Fig.  428.    Herringbone  Expanded-metal  Lath. 


hollow  partition  with  herringbone  lath  on  the  ''allunited"  steel 
studding,  and  also  with  the  "Universal"  steel  corner-bead  made  by 
the  General  Fire-proofing  Company.  Fig.  430  shows  this  corner- 
bead  in  detail. 

Great  stiffness  is  given  to  this  lath  by  the  heavy  longitudinal 
ribs  which  are  at  an  angle  of  about  45°  to  the  original  surface 
of  the  sheet.  The  sheets  are  placed  at  right-angles  to  the  joists 
or  studding,  and  set  in  such  a  way  that  the  longitudinal  ribs 
slope  dozmi  against  the  studding  and  thus  take  a  better  hold  of  the 
plaster.  Fig.  431  shows  in  section  the  right  and  the  wrong  way 
to  apply  the  lath.  No.  12  or  14  "poultry"  staples  are  generally 
used  to  fasten  this  kind  of  lathing  to  wood. 

The  ''Imperial"  or  ''Spiral'^  expanded-metal  lath,  made  by  the 
Imperial  Expanded  Metal  Company,  of  Chicago,  and  shown  in  Fig. 
432,  is  a  somewhat  lighter  and  less  expensive  lath,  and  has  been 


566 


BUILDING  CONSTRUCTION. 


(Ch.  IX)', 


used  lately  in  large  quantities 
and  is  well  recommended  by 
plasterers.  It  is  sold  in  sheets 
48^  inches  long  by  16  inches 
wide,  and  in  bundles  of  25 
sheets.  It  is  used  for  solid  and 
hollow  partitions,  is  easily 
handled  and  quickly  put  on,  and 
the  spiral  twist  makes  a  good 
bond,  as  there  is  an  excellent 
clinch. 

482.  3.  perforated: 
sheet  -  imetal  lath.— 


1  Ifiringbone   Lath  on'Allunited 
Steel  Studding. 


o 

lU 


Fig.  430. 


Universal    Steel  Corner- 
bead. 


to 

m 


I 

(J 

5 


FLOOR 

i:^^ig.  431- 


Jrlerrinebone  Lath, 
of  Applying. 


Manner 


FIRE-PROOF  CONSTRUCTIOX— METAL  LATH.  567 


There  are  some  six  or  more  styles  of  metal  lath  made  from  sheet- 
iron  or  steel  by  perfoiating  the  sheets  so  as  to  give  a  clinch  to  the 
mortar.  The  sheets  are  generally  corrugated  or  ribbed,  also,  in  order 
to  stiffen  them  and  keep  them  away  from  the  wood.  There  is  not  a 
great  difference  between  the  different  styles  of  these  laths,  although 
some  may  possess  certain  advantages  over  the  others. 


Fig.  432.    Imperial  Lath. 


Fig.  433.    Bostwick  Lath. 


Fig.  434.     Kiihne's  Clincher  Lath. 


In  general  those  styles  which  have  the  greatest  amount  of  per- 
forations, or  which  approach  the  nearest  to  the  expanded  lath,  are 
to  be  preferred.  All  of  these  laths  come  in  flat  sheets  about  8  feet 
long,  and  from  15  to  24  inches  wide,  and  are  readily  applied  to 


568  BUILDING  CONSTRUCTION.         (Ch.  IX) 

woodwork  by  means  of  barbed-wire  nails.  The  nails  should  be 
driven  every  3  inches  in  each  bearing,  beginning  in  the  middle 
of  the  sheet  and  working  toward  the  ends.  These  laths  work  very 
nicely  in  forming  round  corners  and  coves.  Metal  lath  should  never 
be  cut  at  the  angles  of  a  room,  but  bent  to  the  shape  of  each  angle 
and  continued  to  the  next  stud  beyond.  This  strengthens  the 
wall  and  prevents  cracks  at  the  angles. 

Of  the  various  forms  of  sheet-metal  lath  in  common  use  the 
''Bostwick"  lath,  made  by  the  Bostwick  Steel  Lath  Company,  of 

Niles,  Ohio,  shown  in  Fig.  433, 
is  perhaps  the  best  known.  It 
is  made  of  sheet-steel,  with  ribs 
every  ^  of  an  inch  in  the  width 
of  the  sheet  and  loops,  ^  by 
inches,  punched  out  between  the 
ribs.  It  has  been  extensively 
used,  and  is  favored  by  plas- 
terers because  it  is  stiff  and  easy 
to  apply  and  requires  less  plaster 
than  other  metal  laths  which  are 
more  open.  The  lath  should  be 
applied  with  the  loop  side  out. 

Kilhncs  Clincher  Lath  is  an- 
other form  of  patented  perfo- 
rated  sheet-metal   lath.     It  is 
manufactured  and  sold  by  the 
Fig.  435.  Rib  Lath.  Truss  Metal  Lath  Company  of 

New  York,  in  bundles  of  9 
sheets  each,  containing  16  square  yards.  The  .size  of  the  sheets  is 
24  by  96  inches,  and  they  may  be  obtained  black,  painted  or  galva- 
nized. It  makes  a  rigid  lath  formation,  and  the  number  and  shape 
of  the  openings  allow  a  good  clinch  for  the  plaster.  Fig.  434  shows 
the  form  of  this  lath. 

Rib  Lath,  made  by  the  Trussed  Concrete  Steel  Company  of 
Detroit,  Mich.,  and  shown  in  Fig.  435,  is  sold  in  sheets  22  by  96 
inches,  11  sheets  and  18  square  yards  to  a  bundle,  weighing  for 
ordinary  metal  lath  gauges  27,  26,  25  and  24,  respectively  2.56, 
3.19,  3.51  and  3.83  pounds  per  yard.    For  painting        cent  per 


FIRE-PROOF  CONSTRUCTION— FURRING.  569 


square  yard  and  for  galvanizing  6  cents  per  square  yard  must  be 
added  to  the  price  for  the  plain  lath. 

483.  4.  OTHER  FORMS  OF  AIETAL  LATH.— There  are 
other  good  forms  of  metal  variously  treated,  already  mentioned 
in  connection  with  reinforcements  for  fire-proof  floors,  which  can 
be  used  as  lath  for  plastered  partitions,  when  properly  prepared  in 
regard  to  size  of  mesh,  etc.,  for  that  purpose. 

Such  are  the  "Welded  Fabric  or  Mesh,"  the  ''Lock-zvoven 
Fabric,''  the  "Steel  Wire  Fabric"  of  triangular  and  square  mesh, 
already  referred  to,  and  other  miscellaneous  forms. 

8.    FIRE-PROOF  FURRING  CONSTRUCTION. 

484.  GENERAL  CONSIDERATIONS.— Furring  in  general 
may  be  classified  under  two  heads :  First,  the  furring  of  construc- 
tive parts  for  purposes  of  protection  against  fire,  dampness,  etc., 
and,  secondly,  the  furring  of  different  parts  for  purposes  of  archi- 
tectural form,  sham  construction,  interior  decoration,  etc. 

The  first  class  may  again  be  subdivided  into  two  varieties,  the 
furring  of  columns,  girders,  beams  and  other  constructive  metal, 
which  variety  has  already  been  considered  ;  and  the  furring  of  out- 
side walls. 

Although  it  is  customary  to  plaster  directly  on  the  outside  walls 
of  fire-proof  buildings,  it  is  necessary  below  grade  and  often  desir- 
able above  grade  to  fur  the  walls  so  as  to  leave  an  air-space,  in 
order  to  prevent  the  passage  of  dampness.  The  furring  material 
used  is  terra-cotta,  hollow  brick  or  some  form  of  metal. 

485.  TERRA-COTTA  AND  HOLLOW  BRICK  WALL 
FURRING- — A  common  shape  of  furring  tile  is  that  shown  in 
Fig.  436,  the  blocks  being  12  inches  square  and  2  inches  thick, 
although  furring  tile  are  made  also  inches  thick^  and  in  both 
larger  and  smaller  sizes.  Thev  are  made  of  dense,  semi-porous  and 
porous  terra-cotta.  With  the  latter  no  nailing  strips  are  required, 
but  it  is  better  in  any  case  to  build  in  solid  porous  terra-cotta  blocks 
whenever  nailings  are  required  for  bases,  wainscotings,  picture- 
moldings,  etc.  It  is  doubtful  if  the  porous  materials  offer  as  good 
protection  from  moisture  as  the  harder  burned  tiles. 

The  ribs  being  set  against  the  wall,  an  air-space  is  formed  which 
checks  the  passage  of  moisture.  The  blocks  should  be  set  with 
the  ribs  vertical  and  fastened  to  the  wall  either  by  driving  flat- 
headed  nails  into  the  joints  of  the  brickwork,  the  heads  of  the  nails 


570 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


being  bent  down  upon  the  tiles,  or  by  using  tenpenny  nails  and 
bending  down  their  heads  upon  the  blocks,  one  nail  being  used  over 
every  third  block  in  every  second  course.  The  blocks  should  not 
be  bedded  in  mortar  at  the  back,  since  this  would  defeat  their 
purpose  by  making  solid  connections  to  carry  the  moisture  through. 

Where  walls  must  be  straightened  or  furred  out  to  a  line  with  the 
face  of  piers,  the  2-inch  blocks  cannot  be  used.  If  the  ceiling 
height  is  not  too  great,  3-inch  partition  blocks  should  be  used.  If 
the  space  is  greater  than  3  inches,  the  blocks  may  be  set  out 
from  the  wall,  leaving  a  clear  air-space  behind  them.  They  should 
be  braced  at  intervals  by  the  use  of  drive-anchors.  Four-inch 
^blocks  can  be  used  without  the  anchors. 


The  face  of  the  blocks  is  grooved  so  that  the  plastering  is  applied 
'directly  upon  them. 

Hollow  furring  bricks,  made  of  brick  clay  and  of  the  same 
dimensions  as  common  bricks,  are  very  generally  used  for  wall 
furring.  Their  cost  is  not  a  great  deal  more  than  that  of  common 
bricks,  and  they  form  the  cheapest  kind  of  furring  with  the  clay 
products.  They  are  built  up  with  the  rest  of  the  wall  and  bonded 
into  it  with  the  usual  header  courses.  Solid  porous  stretchers  are 
made  for  insertion  to  hold  the  trim  and  other  woodwork  by  nailing 
directly  into  them.    Fig.  438  shows  the  hollow  brick  wall  furring. 

Fig.  437  shows  a  good  method  of  furring  the  walls  of  rooms 
used  for  cold-storage,  etc. 


486.    METAL  WALL  FURRING.— Various  forms  of  metal 


Fig.  436.    Furring  Tile.    Common  Shape. 


FIRE-PROOF  CONSTRUCTION— FURRING.  571 


furring  strips  in  connection  with  metal  lath  and  plaster  are  used  to 
fur  the  outside  walls  of  fire-proof  buildings  and  to  obtain  an  air- 
space between  the  wall  and  the  plaster,  thus  greatly  diminishing 
the  passing  of  moisture  and  of  heat  and  the  tendency  to  warp 
during  a  fire. 

Fig.  439  shows  the  Roebling  i-inch  *'V-rib"  metal  furring  with 


wire  lath  and  plaster,  and  ^-inch  air-space.  The  V-ribs  are  woven 
in  every  7^  inches. 

Fig.  440  shows  the  Standard  Concrete  Steel  Company's  ''Channel- 
block"  furring. 

Fig.  441  shows  outside  brick  wall  furred  with  the  "Rib-lath  Tri- 


angular Expanded  Furring  Studs,"  made  by  the  Trussed  Concrete 
Steel  Company. 

Fig.  442  shows  the  ''Allunited  Steel  Side-slot  Furring  Studs,'* 
made  by  the  General  Fire-proofing  Company. 

Fig.  443  shows  the  Prong  Lock  Wireless  Steel  Furring,  made  by 
the  Berger  Manufacturing  Company. 

Fig.  444  shows  outside  wall  furring  with  angle  or  flat  steel  fur- 
ring strips  and  metal  lath,  suggested  by  the  White  Fire-proof  Con- 


-tig-  437.     Wall  Furring  for  Cold-storage  Rooms. 


Fig.   438.    Hollow  Brick  Wall  Furring. 


BUILDING  CONSTRUCTION.  (Cii. 


Fig.  439.     Koebling   Wall  Furring. 


Fig.   440.    Standard   Wall  Furring. 


FIRE-PROOF  CONSTRUCTION— FURRING. 


struction  Company.  The  illustration  shows  the  metal  lath  wall 
furring  brought  out  to  cover  a  duct  and  pipes. 

487.'  FURRING  FOR  ARCHITECTURAL  FORMS.— Dur- 
ing the  last  few  years  metal  furrings  with  metal  lath  have  been 


PLASTER 


Brick  Wall  Furred  and  Plastered 
Rib-Lath  ...n  Tnan-u:ar  Exi»andv<1  Stia-ls 'iti  in _  ..n 


^ecli.as  liipjuu;:!  waii,  ^■■a< 
pandefJ  Stti'ls  arid  Rib-Lath. 


Fig.  441.     Rib  Lath  Wall  Furring. 

largely  used  to  obtain  various  architectural  forms,  such  as  coves^ 
cornices,  false  beams,  arches,  vaulted  ceilings,  inner  domes,  etc., 
and  to  obtain  different  decorative  effects. 

This  kind  of  furring  is  a  sort  of  ''false  construction,"  the  main 


574 


BUILDING  CONSTRUCTION.         (Ch.  IXy 


requirements  of  which  are  to  furnish  a  firm  groundwork  for  the 
metal  lath  and  plaster  and  to  be  incombustible.  It  is  not  designed 
to  carry  weights  of  any  magnitude. 

The  furring  frame  is  fastened  to  the  girders  and  beams  by  bolts 
and  slips,  and  to  the  fire-proofing  by  staples,  toggle-bolts,  nails,  etc. 
The  general  profile  is  formed  by  bending  light  irons,  usually  by 
hand,  on  a  shaping  plate,  to  the  desired  outline.  These  are  secured 
in  position,  longitudinal  rods  fastened  to  their  angles,  and  diagonal 


Fig.    442.    Allunited   Wall  Furring. 


bracing  rods  set  for  deep  furrins^s,  after  which  the  metal  lath  is 
applied.  Usually  not  more  than  from  to  2  inches  of  plaster 
are  required  to  give  desired  profiles,  and  not  more  than  ^  of  an 
inch  of  plaster  for  plane  surfaces.  The  spacing  of  the  furring 
depends  upon  the  kind  of  metal  lath  used,  the  usual  spacing  being 
12  or  16  inches. 

Metal  furring  and  lath  are  used  also  for  covering  pipe  casings, 
wall  chases,  etc.,  with  fire-proofing  material  filled  in  solidly  at  each 
floor  level  to  act  as  fire  stops  between  stories. 


FIRE-PROOF  CONSTRUCTION— FURRING. 


Fig.  445  shows  a  method  of  furring  and  lathing  for  cornice 
profile,  around  a  steel  plate-girder  dropped  below  the  ceiling,  54- 
inch  rib-stiffened  lath  being  applied  to  the  furring  or  brackets  which 
have  been  bent  to  the  required  outlines  and  set  i6  inches  on  centers. 


Fig.  443.     Berger  Prong-lock  Furring. 


Fig.  446  shows  furring  and  lathing  for  orTiamental  false  girder 
with  cornice  profile.  In  this  case  the  bottom  of  the  constructional 
girder  is  almost  flush  with  the  bottom  of  the  floor  beams. 


Fig.  444.    White  System  of  Furring  Walls,  Pipes  and  Ducts. 


Fig.  447  shows  furring  for  ornamental  effects  in  plaster  and 
electric  lighting  around  constructional  I-beam. 

■Fig.  448  shows  furring  for  the  foundation  of  a  papier-mache 
false  ceiling'  beam,  all  hung  from  steel  floor  beam  and  ceiling. 


576 


BUILDING  CONSTRUCTION. 


(Ch,  TX) 


Both  wire  lath  and  expanded-metal  have  been  very  extensively 
used  for  furring  elaborate  ceilings,  beams,  arches,  vaults,  etc.,  in 
public  buildings ;  and  wherever  such  furring  has  been  removed  or 
examined  after  a  term  of  years,  it  has  always,  so  far  as  known, 
been  found  to  be  in  good  condition  and  free  from  rust. 


Fig.  445.    Steel  Beam  Furring  for  Plaster  Moldings. 

The  larger  portion  of  the  plaster  beams,  ceilings,  domes,  etc.,  of 
the  Congressional  Library  are  formed  with  expanded-metal  on  iron 
furrings,  as  were  also  the  very  elaborate  ceiling  of  the  dining-room 
in  the  Chicago  Athletic  Club  and  the  domes  and  panelled  ceilings 
'of  the  New  York  Clearing  House.  In  the  main  corridor  of  the 
Worthington  Building  in  Chicago  an  elaborate  vaulted  mosaic  ceil- 


Fig.    446.    Furring   for   False  Girders. 


ing  is  supported  by  a  background  of  hard  mortar  on  expanded- 
metal. 

The  extent  to  which  both  wire  lath  and  expanded-metal  may  be 
used  in  forming  a  base  for  mortar  and  cement  appears  to  be  un- 
limited 


FIRE-PROOF   CONSTRUCTION— FURRING, 


S77 


When  hollow  tiles  are  used  for  fire-proofing,  the  grounds  for  the 
cornices  are  sometimes  formed  of  terra-cotta,  as  shown  in  Fig.  449. 
Such  grounds  make  a  firmer  base  on  which  to  carry  the  heavy- 


Fig.  447.    Furring  Steel  Girder  for  Decorations. 

stucco,  and  the  plastering  is  not  as  liable  to  be  broken  by  streams 
of  water  in  case  of  fire.  They  are,  therefore,  often  preferred  to 
metal  grounds,  and  have  been  largely  used  in  the  United  States 
Government  buildings  where  the  ceilings  have  been  of  tile. 


Papier-mache  False  Girder. 


The  various  pieces  forming  the  grounds  should  be  bolted  to  the 
floor  construction  with  ^-inch  T-head  bolts  spaced  not  over  12 
inches  apart  longitudinally,  and  with  at  least  two  bolts  to  each  piece. 

These  terra-cotta  grounds  have  usually  been  made  by  manufac- 


578 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


turers  of  flue-linings  and  pipes,  as  their  machinery  is  better  adapted 
to  this  purpose  than  that  used  for  making  fire-proof  tiles. 

9.    FIRE-PROOF  INTERIOR  FINISH. 

488.  GENERAL  DESCRIPTION.— Various  incombustible 
materials  are  used  for  the  interior  finish  in  some  important  high 
buildings  and  also  in  some  of  ordinary  height,  with  the  object  of 
making  them  more  nearly  fire-proof  in  all  details.  The  materials 
used  may  be  terra-cotta,  cement,  the  incombustible  compositions 
already  mentioned  as  used  for  fire-proof  floor  coverings,  metal  or 
wood  covered  with  metal. 


Fig.  449.     Terra-cotta  Cornice  Grounds. 


The  last  two  do  not  belong  to  masons'  work,  and  are  simply 
referred  to  here. 

Molded  hollow  terra-cotta  tiles  have  been  used  as  a  substitute 
•  for  wood  inside  finish,  such  details,  for  example,  as  door  jambs  and 
:asings,  baseboards  and  picture-moldings  being  made  of  specially 
formed  tiles,  built  in  place  with  the  tile  partition  blocks  left  in  sight 
and  painted  with  the  rest  of  the  interior  finish. 

Very  hard-setting  special  cements  also,  such  as  Keene's  Cement, 
are  used  for  the  interior  trim  of  fire-proof  buildings.  The  moldings 
are  run  directly  on  the  wall  plaster  or  on  the  fire-proofing,  often 
returning,  as  for  example,  on  brick  walls,  to  form  the  jambs.  The 
cement  may  be  painted,  the  angles  may  easily  be  made  sharp  and 
true,  and  the  material  is  hard  enough  to  stand  any  ordinary  usage. 


9 


FIRE-PROOF  CONSTRUCTION—STAIRS. 


579 


10.    FIRE-PROOF  STAIR  CONSTRUCTION. 

489.  GENERAL  DESCRIPTION.— The  following  is  a  gen- 
eral classification  of  the  principal  kinds  of  stairs  constructed  in  fire* 
proof  buildings : 

1.  Stone  Stairs. 

2.  Brick  Stairs,  (i)  with  or  (2)  without  slate  or  marble  treads 

or  risers. 

3.  Terra-cotta  Hollow  Block  Stairs,  each  step  in  one  piece. 

4.  Guastavino  System  of  Flat  Clay  Tiles. 

5.  Metal  Stairs,  Cast-iron  or  Steel. 

(1)  Without  Slate  or  Marble  Treads. 

(2)  With  Slate  or  Marble  Treads. 

6.  Concrete  Stairs. 

(1)  Without  Reinforcement. 

(a)  Monolithic,  with  or  without  slate  or  marble  treads 

or  risers. 

(b)  With  steps  cast  separately  and  set  in  place. 

(2)  With  Reinforcement,  with  Construction  Steel  Stringers, 

or  with  Reinforced  Concrete  Stringers. 

(a)  With  wire  or  lath  reinforcement. 

(b)  With  plates  like  "ferroinclave,"  ''ferrolithic,"  etc., 

for  treads  and  risers,  plastered. 

(c)  Without  slate  or  marble  treads  and  risers. 

(d)  With  slate  or  marble  treads  and  risers. 

1.  Stone  steps  and  stairs  have  already  been  referred  to  in  Chap- 
ter VI,  ''Cut  Stonework."  Stone,  however,  from  the  point  of  view 
of  fire-resistance,  is  not  a  good  material  for  stair  construction. 

2.  Brick  stairs  have  been  described  in  Chapter  VII,  ''Bricks  and 
Brickwork." 

3.  Terra-cotta  hollow  block  stairs  have  been  successfully  built. 
In  one  building,  the  Amelia  apartment-house,  at  Akron,  Ohio, 
each  step  was  one  entire  block  of  hard-burned,  glazed  terra-cotta, 
4  feet  long,  6^  inches  high  and  11  inches  wide,  not  including  the 
nosing  and  cove  of  the  upper  tread  surface,  the  extreme  width  of 
the  upper  surface  being  14  inches.  The  steps  were  made  by  forcing 
the  clay  through  a  die  in  the  same  manner  as  for  fire-proof  tiles. 
They  were  made  with  molded  nosings  and  with  smooth  finish.  The 
blocks  were  made  with  two  vertical  webs,  were  supported  by  the 
partition  walls,  and  were  found  to  be  of  ample  strength.  Another 
prominent  example  of  terra-cotta  hollow  block  stairs  is  in  the  model 


SSo 


BUILDING  CONSTRUCTION.         (Ch.  IX) 


fire-proof  building  erected  for  the  Fire  Insurance  Underwriters' 
laboratory,  in  Chicago,  according  to  the  methods  and  with  the 
materials  of  the  National  Fire-proofing  Company. 

4.  The  R.  Guastavino  Company  have  erected  a  number  of  stair- 
cases, using  their  flat  clay  tiles  in  cement  without  iron  work  of  any 
kind,  and  with  a  resulting  advanced  type  of  fire-proof  construction. 

5.  Iron  and  steel,  while  used  more  than  any  other  incombustible 
material  in  staircase  construction,  cannot  be  classed  with  the  fire- 
proof materials,  when  unprotected.  Of  the  two  exposed  metals, 
the  thin  facing  sheets  of  steel  are  inferior  to  those  of  cast-iron, 
as  they  warp  in  intense  heat.  It  is  desirable  to  do  away  with  as 
much  iron  as  possible  in  really  fire-proof  stair  construction.  Regard- 
ing slate  and  marble  treads  and  platforms,  it  may  be  said  that  they 
should  always  have  ample  support  under  the  middle  parts  as  well 
as  under  the  edges,  as  they  crumble  away  from  intense  heat. 

6.  Since  the  iwtroduction  of  reinforced  concrete  construction, 
many  staircases  have  been  built  of  concrete  with  variations  in  detail 
as  briefly  outlined  in  the  foregoing  classifications  in  this  article. 
A  good  construction  results  from  the  use  of  marble  or  slate  treads 
set  on  reinforced  concrete,  which  usually  consists  of  a  wet,  rich 
mixture  with  small  aggregate  for  convenient  casting  into  the 
desired  shapes.  The  stairs  of  the  new  Government  Printing  Office 
at  Washington  are  constructed  of  reinforced  concrete  steps  and 
platforms,  supported  on  the  sides  by  steel  girders  and  stringers 
which  are  enclosed  in  solid  concrete.  The  reinforcement  near  the 
lower  side  of  the  sloping  mass  of  concrete  forming  the  staircase 
run  is  accomplished  by  the  use  of  ^-inch  bars,  7  inches  on  centers 
parallel  with  the  treads  and  rises,  and  of  ^-inch  bars  2  feet  on  cen- 
ters running  up  the  string.  Slate  and  marble  are  used  for  the  treads 
and  risers. 

Fig.  450  shows  the  above-described  type  of  reinforced  concrete 
stairs. 

Fig.  451  shows  the  details  of  the  design  of  the  reinforced  concrete 
stairs  in  the  Ketterlinus  Lithographic  Manufacturing  Company's 
building,  Philadelphia.* 

Fig.  452  shows  a  section  through  the  treads  and  risers  of  stairs 
constructed  with  the  corrugated  sheet-metal  known  as  "Ferroin- 
,  clave,"  in  which  the  treads  and  risers   made  of  these  sheets  are 


*  Designed  by  Ballinger  &  Perrot,  architects  and  engineers,  Philadelphia. 


FIRE-PROOF  COSSTRUCTIOK— STAIRS. 


S8i 


Fig.  450.    Reinforced  Concrete  Stairs. 


11^ 


'   v^y-^^^l^i^^-^x^^^^^  ''i  r  z^'^-  j:^  Ki^^^ 

^^//7  forced ^Co/7cre/(f  /^oof//;^-^  - 

Fig.  451.    Reinforced  Concrete  Stairs.    Ketterlinus  Building,  Philadelphia, 


/"/oar 


582 


BUILDING  CONSTRUCTION,         (Cii.  IX) 


either  built  between  walls  or  partitions,  or  built  with  ''open  strings" 
of  steel  channels  or  I-beams,  to  which  they  are  bolted  by  means  of 
lugs  or  brackets  screwed  to  or  cast  on  the  strings.  About  2  inches 
of  cement  are  put  over  the  metal  sheets  and  they  are  plastered  on 
the  under  side,  the  treads  and  risers  being  frequently  of  slate  or 
marble. 

II.    MISCELLANEOUS   DEVICES  IN  FIRE-PROOF  BUILDINGS. 

490.  GENERAL  DESCRIPTION.— These  additional  devices 
will  be  simply  enumerated  here,  as  they  do  not  come  under  the  head 
of  masons'  work. 


They  may  be  classified  as  ''protecting  devices,"  "precautionary 
>devices"  and  "devices  for  extinguishing  fires." 

To  these  additional  devices  belong  the  different  types  of  window- 
protection,  such  as  tin-covered  wood  shutters,  steel  shutters,  metal 
frames  and  sashes,  wire-glass,  automatic  alarms,  water-curtains, 
automatic  sprinklers,  stand-pipes,  hose-reels,  etc. 

For  a  description  of  these  see  Chapter  XXIII,  "Fire-Proofing  of 
Buildings,"  in  the  "Architect's  and  Builder's  Pocket-Book,"  by 
Frank  E.  Kidder. 

12.    FIRE-PROOF  CONSTRUCTION  FOR  DWELLINGS  AND 


491.  GENERAL  DESCRIPTION.— Under  the  general  subject 
of  fire-proofing,  reference  should  be  made  to  recent  methods  of  fire- 


Fig.  452.    Reinforced  Concrete  Stairs.  Ferroinclave. 


OTHER  BUILDINGS  OF  MODERATE  SIZE. 


FIRE-PROOF  DWELLINGS.  583 

proof  construction  used  for  dwellings  especially  and  for  other 
classes  of  buildings  of  moderate  size  and  cost. 

Besides  the  usual  methods  described  in  the  foregoing  pages, 
which  pertain  more  particularly  to  buildings  with  outside  brick 
bearing  walls  or  with  the  skeleton  frame  and  brick  curtain-walls, 
there  may  be  mentioned  also  the  method  employing  concrete,  solid 
or  in  the  form  of  hollow  blocks,  or  hollozv  lerra-cotta  tile  blocks 
for  the  construction  of  the  outside  walls. 

The  concrete  construction  is  considered  in  Chapter  X. 

492.  TERRA-COTTA  HOLLOW  TILE  OUTSIDE  WALLS. 
— Fig.  453*  shows  the  general  constructional  details  of  a  dwelling 


Fig.   453.    Terra-cotta  Hollow  Tiles  for  Outside  Walls. 


in  which  these  materials  were  used.  The  exterior  walls  are  built 
of  doubled  6-inch  and  doubled  4-inch  hollow  tiles,  set  with  the  ribs 
vertical,  the  partitions  of  4-inch  tiles  and  the  floors  and  roof 
according  to  the  "Johnson"  floor  system,  4-inch  tiles  being  generally 
used. 

The  foundations  are  of  concrete,  and  reinforced  concrete  is  used 
for  interior  girders  and  exterior  lintels.  The  spans  of  floors  and 
roof  range  from  16  to  20  feet.  The  chimneys,  balustrades  and 
many  other  details  are  built  of  hollow  tiles.    The  roof  is  flat,  the 


*  Fire-proof  residence  of  Mr.  G.  E.  Bergstrom.  architect,  Los  Angeles,  California. 
Courtesy  of  the  National  Fire-proofing  Company. 


584 


BUILDING  CONSTRUCTION.         (Cii.  IX) 


Fig.  455.    Terra-cotta  Outside  Wall  and  Lintel  Construction. 


FIRE-PROOF  DWELLINGS. 


586  BUILDING  CONSTRUCTION.         (Ch.  IX) 

sloping  eaves  being  covered  with  ''Mission"  tiles.  No  steel  is  used 
for  construction  except  as  a  tension  material.  The  entire  exterior 
is  coated  with  cement  and  fine  gravel,  and  treated  with  acid  to 
remove  the  cement  from  the  exposed  surface  and  to  leave  the 
gravel  visible.  The  eaves  are  carried  on  wooden  frames  supported 
by  and  tied  to  the  cornice  brackets,  as  shown  in  the  figure. 

Fig.  454  shows  details  of  another  building  with  hollow  tile  outside 
walls  and  with  hollow  tile  and  reinforced  concrete  floor  construction. 

Fig.  455  shows  details  of  hollow  tile  and  reinforced  concrete 
lintel  construction  over  an  opening  in  8-inch  hollow  tile  walls. 


Fig.  457.    Terra-cotta  Phoenix  Outside  Wall. 


Fig.  456*  shows  vertical  section  of  fire-proof  dwelling,  indicating 
the  terra-cotta  materials  and  construction. 

Fig.  457  shows  the  general  method  of  constructing  the  'Thoenix" 
outside  wall  of  hard-burned  hollow  clay  blocks,  with  grooves  in 
them  at  tops  and  bottoms  to  receive  the  courses  of  band-iron  hori- 
zontally and  continuously.  These  blqcks  are  made  by  Henry 
Maurer  &  Son,  New  York,  and  come  in  various  convenient  sizes, 
usually  8  by  12  inches  in  height  and  length,  and  in  4-,  6-,  8  and  12- 
inch  thicknesses.  The  illustration  shows  the  wall  with  a  pier,  and 
with  smooth  surfaces  and  also  with  ribbed  surfaces  for  plastering. 


*  See  "Fire-proof  Residences,"  by  Charles  E.  White,  Jr.,  architect,  Chicago,  published 
by  the  National  Fire-proofing  Company.     Drawing  reproduced  by  permission. 


EARTHQUAKE-RESISTING  CONSTRUCTION.  587 


13.    EARTHQUAKE-RESISTING  CONSTRUCTION  IN  FIRE- 
PROOF BUILDINGS. 

493.  GENERAL  DESCRIPTION.— Fig.  458  shows  the  geii- 
■eral  system  of  construction  designed  to  resist  the  destructive  effects 
of  earthquakes,  and  patented  by  Air.  Peter  II.  Jackson,  of  San 
Francisco,  Cahfornia. 

The  figure  is  a  perspective  view  of  a  sohd  front  wall  and  a  return 
wall  having  a  window  opening,  both  walls  being  between  steel 


Fig.   458.     Jackson   Earthquake-proof  Construction. 


columns  and  enclosing  them.  Tie-rods  ^  of  an  inch  in  diameter 
extend  as  shown  horizontally  along  the  middle  thickness  of  the  front 
wall  with  their  ends  fastened  to  the  columns.  In  the  return  wall 
two  rods  are  shown  extending  vertically  with  their  ends  fastened 
to  the  top  and  bottom  cross  I-beams.  These  vertical  rods,  with  the 
anchors,  are  so  placed  as  to  hold  and  stiffen  the  edges  of  the  wall 
forming  the  window  or  door  opening,  while  a  horizontal  tie-rod  is 


588 


BUILDING  CONSTRUCTION. 


(Ch.  IX) 


shown  extending  across  the  wall  at  the  bottom  of  the  opening- 
beneath  the  window  sill.  These  tie-rods  have  to  be  adjusted  in 
places  to  meet  the  requirements  of  every  case.  Clamps  are  shown 
on  the  two  front  columns  to  which  the  ends  of  the  tie-rods  are 
secured ;  but  they  may  be  used  in  the  same  way  when  fastened  on 
the  cross  beams.  They  are  inexpensive,  and  in  many  cases  have  to 
be  used  in  order  that  the  tie-rods  may  extend  through,  as  near  the 
middle  thickness  of  the  wall  as  possible,  as  shown  in  Figs.  459  and 
460.  The  manner  of  fastening  the  clamps  to  the  columns  is  illus- 
trated in  these  figures.  The  tie-rods  are  fastened  to  the  plates  G 
and  the  bolts  D  hold  the  plates  to  the  column. 

The  cross-anchor  portion  that  extends  through'  the  wall  is  usually 
made  of  i-inch  by  j/{J-inch  flat  iron.    Its  flat  part  is  shaped  by  bend- 


Fig.  459.     Jackson  Construction.     Column  Clamp. 


ing  it  round  an  iron  rod  and  the  end  plates  are  attached  as  shown 
in  Fig.  461.  These  anchors  are  strung  on  the  horizontal  tie-rods,  as 
shown  in  the  front  wall,  or  strung  on  the  vertical  tie-rods  at  the  side 
of  the  window  opening,  as  shown  in  the  return  wall,  Fig.  458. 

Fig.  462  shows  a  cross-section  of  a  brick  or  concrete  wall  with 
the  tie-rod  in  its  middle  and  a  cross-anchor  strung  on  the  rod.  Fig. 
463  shows  another  view  of  wall  and  anchors,  the  tie  having  three 
cross-anchors  extending  vertically  through  the  middle  of  the  wall. 
The  end  plates  of  the  anchors  are  shown  extending  their  thickness 
outside  of  the  wall ;  but  for  a  face-brick  wall  the  outside  plate  of 
the  anchor  is  just  flush  with  the  face  of  wall  and  the  width  of  two 
face-bricks,  with  a  countersunk  hole  in  the  middle  of  its  height,  the 
tenon  of  crosspiece  being  rivetted  flush  with  the  face  of  the  plate,, 
so  that  the  latter  is  not  distinguished  from  the  other  face-bricks  of 


EARTHQUAKE-RESISTING  COXSTRUCTIOX. 


Fig.  462.    Ja'-'"=n'-'  Tr^rictruction.  Wall 
Construction. 


590 


BUILDING  CONSTRUCTION,  (Ch.  IX) 


the  wall.  The  inside  plate  is  on  the  inside  face  of  the  wall.  The 
front  plates  of  these  anchors  for  a  face-brick  wall  are  galvanized 
and  then  well  painted  to  avoid  discoloration  by  rust. 

The  clamping  pieces.  Figs.  459 
and  464,  admit  of  the  tie-rods  being 
placed  at  any  distance  up  or  down 
on  the  columns  and  to  the  right  or 
left  of  the  cross  beams. 


14.    PELTON'S  SYSTEM  OF  RE*- 
LEASED  WALL  FACING. 

494.  GENERAL  DESCRIP- 
TION.— During  the  years,  from 
1892  to  1896,  Mr.  John  Cotter  Pel- 
ton,  architect,  developed  and  pat- 
ented a  system  of  released  wall 
facing  which  met  with  commenda- 
tion from  many  architects,  and  which 


ri  i 

1 

i 

l_  1 

Fig.  463.    Jackson  Construction.   Wall   Fig.  464.    Jackson  Construction.    Clamping  Piece. 

Construction. 


the  author  believes  to  be  sufficiently  practicable  to  interest  all  archi- 
tects and  students.  The  essential  feature  of  this  invention  is  the 
idea  of  supporting  a  costly  facing  of  stone,  marble  or  terra-cotta 
from  a  wall  of  common  masonry,  or  from  a  steel  frame,  by  means 
of  metal  anchors  and  brackets,  which  hold  the  facing  away  from 
the  wall  or  frame  and  also  permit  of  its  being  set  after  the  sup- 
porting wall  is  completed.  The  general  principle  of  construction 
is  quite  clearly  indicated  by  Fig.  465. 

The  five  advantages  claimed  for  this  system  are:  First,  economy 


EARTHQUAKE-RESISTING  CONSTRUCTION.  591 

of  material  in  the  facing ;  secondly,  saving  in  time  required  to  com- 
plete the  building  ready  for  occupancy ;  thirdly,  protection  against 
the  penetration  of  moisture  ;  fourthly,  elimination  of  the  bad  effects 
of  settlement  in  the  walls  and  the  loosening  of  the  facing  from  the 
backing;  fifthly,  protection  against  exterior  fire.  Of  these  advan- 
tages the  fiVst  and  second  will  probably  have  the  most  influence  in 
extending  the  use  of  the  system,  as  they  have  a  direct  bearing  upon 
the  cost  and  financial  returns  of  the  building.  The  other  advantages. 


Fig.  465.     Pelton   System   of  Released  Wall  Facing, 

however,  are  perhaps  the  most  important  from  a  constructive  stand- 
point. 

As  the  facing  is  treated  merely  as  an  external  covering,  prin- 
cipally for  architectural  effect,  and  has  nothing  to  support,  it  can 
be  made  very  thin,  thus  permitting  the  use  of  expensive  materials^ 
which,  with  the  ordinary  method  of  construction,  would  be  pro- 
hibited on  account  of  the  cost. 

The  anchors  which  support  the  facing  being  built  into  the  sup- 


592  BUILDIXG  CONSTRUCTION.  (Ch.  IX) 

porting  wall  as  it  progresses,  the  facing  can  be  applied  after  the 
roof  is  on  and  while  the  bnilding  is  being  finished  on  the  inside,  or 
even  after  the  building  is  occupied.  Hence  a  building  faced  with 
marble  under  this  system  could  be  completed  ready  for  occupancy 
in  about  the  same  time  that  would  be  required  if  the  walls  were 
of  plain  brickwork,  ample  time  being  allowed  for  cutting  and 
setting  the  facing,  and  even  for  quarrying  the  stone.  In  fact,  any 
iniavoidable  delays  with  the  stonework,  such  as  strikes,  unfavorable 
weather,  etc.,  need  not  delay  the  finishing  of  the  interior  of 
the  building. 

As  a  protection  from  dampness  the  advantage  of  this  system  is 
obvious,  as  a  continuous  air-space  is  provided  between  the  facing 
and  the  supporting  wall,  with  only  the  metal  anchors  connecting 
the  two. 

The  facing  being  applied  after  the  supporting  wall  is  completed, 
all  settlement  in  the  latter  will  have  taken  place  before  the  orna- 
mental work  is  set,  thus  avoiding  the  cracks  which  frequently  occur 
in  facings  that  are  bonded  into  a  brick  backing.  Of  course  any  set- 
tlement in  the  foundations  would  afifect  the  facing  as  well  as  the  sup- 
porting wall.  A  facing  supported  in  this  way  will  serve  also,  while 
it  endures,  to  protect  the  supporting  wall  from  external  fires ;  and 
should  a  portion  or  all  of  the  facing  be  injured  beyond  repair,  it  can 
be  removed  and  new  pieces  substituted.  A  facing  of  either  marble 
or  limestone  would  probably  protect  the  structural  wall  from  serious 
damage  from  any  ordinary  fire ;  and  even  when  the  fire  is  inside  the 
building  this  method  of  facing  is  likely  to  prove  an  advantage.  In 
such  cases  the  flames  generally  destroy  the  stonework  around  the 
exterior  doors  and  windows,  and  with  a  released  facing  injured 
stones  can  be  replaced  if  the  structural  wall  is  not  weakened. 

This  system  of  construction  was  adopted  in  a  few  buildings  in 
California,  of  which  the  Public  Library  at  Stockton,  a  building  in 
the  Renaissance  style  and  designed  by  Mr.  Pelton,  is  one  of  the  most 
.elaborate. 

This  building  stands  on  a  corner  and  has  exposed  about  210  feet 
of  frontage,  the  whole  of  which  is  of  white  marble  on  a  light  gray 
granite  foundation  wall  7  feet  high.  The  structural  walls  are  of 
brick,  24  inches  in  thickness,  and  the  ashlar  is  2^  inches  thick,  with 
an  air-space  of  2%  inches.  The  whole  of  the  work  on  this  building, 
except  the  finishing  coat  of  plaster  and  the  interior  woodwork,  was 


EARTHQUAKE-RESISTING  CONSTRUCTION.  593 

completed  before  the  marble  for  the  fagade  was  delivered  upon  the 
ground.  The  whole  cost  of  the  exterior  marble  work  was  less  than 
$17,000,  in  which  is  included  not  less  than  $3,000  for  carving  and 
the  cost  of  six  monolithic  columns  16  feet  in  height. 

The  anchors  or  carriers  in  this  building  were  all  set  and  adjusted 
by  an  engineer,  so  as  to  secure  perfect  alignment,  and  no  difficulty- 
appears  to  have  been  encountered  in  any  portion  of  the  work,  the 
appearance  of  the  building  on  completion  being  the  same  as  if  con- 
structed in  the  ordinary  way. 

At  one  time  during  the  progress  of  the  work  there  were  men  at 
work  at  not  less  than  five  different  parts  of  the  building  and  on 
eight  different  levels. 

Every  stone  sent  to  the  staging  as  correct  in  size  was  set  without 
trimming;  in  fact,  fitting  and  trimming  were  not  known  upon  the 
staging.  The  only  cutting  known  to  have  been  done  in  the  work  of 
setting  was  the  small  amount  of  channelling  required  for  the  carriers, 
and  this  work  hardly  occupied  the  time  of  one  workman. 

The  shape  and  size  of  the  carriers  or  anchors  will  necessarily 
depend  a  good  deal  upon  the  size  and  weight  of  the  pieces  to  be 
supported.  The  shape  of  some  of  the  carriers  used  in  the  Stock- 
ton Library  is  shown  in  Fig.  465.  To  insure  the  successful  setting 
of  the  facing  the  carriers  must  be  set  with  great  exactness,  and  Mr. 
Pelton  recommends  that  an  engineer  be  employed  to  give  both  the 
^horizontal  and  plumb  lines. 

The  window  frames  should  be  set  before  the  facing  and  the  latter 
built  around  them. 

As  stated  in  the  first  paragraph,  this  system  of  construction  was 
patented  by  Mr.  Pelton. 


Chapter  X. 


Concrete  and  Reinforced  Concrete 
Construction. 


I.  CONCRETES. 

495.  DEFINITIONS. — Concrete  is  really  an  artificial  stone.  It 
is  made  by  mixing  cement,  or  some  similar  material,  with  sand 
and  with  different-sized  pieces  of  broken  stone,  gravel,  cinders,  slag, 
coke,  broken  bricks,  or  other  coarse  stuff  of  like  nature. 

The  Matrix. — The  active  element  of  the  concrete  is  the  cement, 
which  is  sometimes  called  the  ''matrix." 

The  Aggregate. — The  inert  elements  of  the  concrete  are  the  sand, 
broken  stone,  etc.,  which  are  called  the  "aggregate." 

Rubble  Concrete  is  concrete  in  which  large  stones  are  placed. 

Bituminous  Concrete. — Asphalt,  coal-tar  and  pitch  are  used  with 
sand  to  make  bituminous  mortar  and  concrete.  It  is  used  in  road- 
way pavements  and  in  foundations  for  machinery  when  vibration 
is  to  be  avoided. 

Reinforced  Concrete  is  a  compound  or  heterogeneous  material, 
composed  of  a  metal  skeleton  work  imbedded  in  a  mass  of  concrete 
or  cement  mortar.  Other  names  for  it  are  ''ferro-concrete"  and 
''armored  concrete."  It  is  plain  concrete  to  which  is  given  the 
requisite  strength  in  tension  and  sometimes  also  in  compression  by 
the  imbedding  of  steel  or  wrought-iron  rods,  and  which  also  has  its 
resistances  to  lonigtudinal  and  shearing  stresses  assisted  by  these 
same  or  similar  rods. 

496.  EARLY  USE  OF  CONCRETE.— Concrete  has  been  used 
from  very  early  times  by  the  Egyptians  and  the  Romans,  and  it  was 
probably  known  to  the  ancient  inhabitants  of  Mexico  and  Peru  and 
other  countries.  It  was  used  by  the  Romans  in  aqueducts,  sewers, 
water-mains,  foundations,  buildings,  roads,  etc.,  and  possessed  such 
strength  and  toughness  that  many  relics  of  works  in  which  it  was 
used  still  remain. 

497.  PRESENT  USES  OF  CONCRETE.— The  use  of  concrete 


594 


CONCRETES. 


595 


is  increasing  every  year,  and  it  may  be  considered  one  of  the  most 
valuable  of  the  building  materials.  It  is  especially  useful  in  the 
following  kinds  of  construction:  Heavy  foundation  work;  under- 
ground subways  and  tunnels;  foundations  of  engines  or  machinery; 
walls  and  foundations  of  heavy  walls  or  piers ;  sidewalks  or  floors ; 
constructions  in  which  the  stresses  are  chiefly  compressive,  such  as 
arches,  dams,  retaining-walls,  penstocks,  bridges,  abutments,  sewer 
and  water  conduits,  reservoirs ;  foundations  for  roadway  pavements ; 
fortification  work,  on  account  of  its  resistance  to  the  penetration  of 
large  projectiles;  submarine  work,  where  it  may  be  laid  when 
necessary  without  excluding  the  water;  breakwaters,  dikes  and 
wharves ;  concrete  building  blocks,  etc. 

It  is  also  well  adapted  to  the  construction  of  vats  or  tanks  holding 
liquids  which  have  a  destructive  action  upon  iron  or  wood. 

When  concrete  is  properly  reinforced  the  variety  of  its  uses  is 
almost  endless.  It  then  becomes  adapted  to  beam  and  column 
construction,  to  floor  and  roof  arches,  chimneys,  standpipes,  piles, 
railroad  ties,  fence  posts,  thin  walls,  bridge  floors,  and  to  many 
other  kinds  of  construction  mentioned  in  the  foregoing  paragraphs 
of  this  article. 

It  is  quite  possible  also  to  cast  concrete  in  molds  in  a  manner 
similar  to  that  in  which  plaster  of  Paris  is  run,  and  there  have  been 
many  recent  attempts  to  treat  concrete  surfaces  decoratively,  which 
have  met  with  considerable  success.  (See  also  Article  525,  "Uses 
of  Reinforced  Concrete-  Construction.") 

498.  SELECTION  OF  MATERIALS.— The  ordinary  com- 
position of  concrete  is  a  mixture  of  cement,  sand,  gravel  or  crushed 
stone,  or  gravel  and  crushed  stone  together,  and  water. 

It  is  better  to  use  Portland  cement  for  concrete  for  nearly  all 
classes  of  work,  as  it  has  generally  greater  uniformity  and  greater 
strength,  and  consequently  yields  better  results  than  do  natural 
cements  at  the  same  or  lower  cost,  when  mixed  with  larger  propor- 
tions of  sand  and  stone. 

The  sand  is  better  when  clean  and  composed  of  a  mixture  of 
coarse  and  fine  grains. 

Broken  stone  or  gravel,  or  both  together,  may  be  used.  If  the 
gravel  is  clayey  or  dirty  it  should  be  washed  before  mixing.  If 
broken  stone  is  selected,  it  is  usual  to  limit  the  maximum  size  to 
23/2  inches.    Smaller  maximum  sizes  are  sometimes  used  to  give 


596 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


finer  surfaces.  Graded  stone,  such  as  '^crusher  run,"  or  gravel 
from  }i  to  2  inches  in  size  give  the  best  results. 

499.  PROPORTIONS  OF  MATERIALS.— The  following 
four  proportions  for  different  mixtures  are  given  by  Taylor  & 
Thompson*  as  a  guide  to  the  selection  of  materials  for  various 
classes  of  work,  and  differing  from  each  other  simply  in  the  rela- 
tive quantity  of  cement.    They  are  based  upon  fair  average  practice : 

''A  Rich  Mixture. — For  reinforced  engine  or  machine  founda- 
tions subject  to  vibrations,  for  reinforced  floors,  beams  and  columns 
for  heavy  loading,  for  tanks  and  other  water-tight  work.  Propor- 
tions 1:2:4;  that  is,  I  barrel  (4  bags),  packed  Portland  cement  (as 
it  comes  from  the  manufacturer),  to  2  barrels  (7.6  cubic  feet),  loose 
sand,  to  4  barrels  (15.2  cubic  feet),  loose  gravel  or  broken  stone- 

"A  Medium  Mixture. — For  ordinary  machine  foundations,  thin 
foundation  walls,  building  walls,  arches,  ordinary  floors,  sidewalks 
and  sewers.  Proportions  1:2^:5;  that  is,  i  barrel  (4  bags), 
packed  Portland  cement,  to  2^^  barrels  (9.5  cubic  feet),  loose  sand, 
to  5  barrels  (19  cubic  feet),  loose  gravel  or  broken  stone. 

''An  Ordinary  Mixture. — For  heavy  walls,  retaining  walls,  piers 
and  abutments,  which  are  to  be  subjected  to  considerable  stress. 
Proportions  1:3:6;  that  is,  i  barrel  (4  bags),  packed  Portland 
cement,  to  3  barrels  (114  cubic  feet),  loose  sand,  to  6  barrels  (22.8 
cubic  feet),  loose  gravel  or  broken  stone. 

"A  Lean  Mixture. — For  unimportant  work  in  masses  where  the 
■concrete  is  subjected  to  plain  compressive  stress,  as  in  large  foun- 
dations supporting  a  stationary  load  or  in  backing  for  stone 
masonry.  Proportions  1:4:8;  that  is,  i  barrel  (4  bags),  packed 
Portland -cement,  to  4  barrels  (15.2  cubic  feet),  loose  sand,  to  8 
barrels  (30.4  cubic  feet),  loose  gravel  or  broken  stone." 

TABLE  XXX. 

Materials  for  One  Cubic  Yard  of  Portland  Cement  Concrete. 


Cement. 

Proportions.  Barrels. 

1:2:  4  1-57 

1 :5  1.29 

1:3:  6  1. 10 

1 :4 :  8  0.85 

500.    QUANTITIES  OF 


Sand. 
Cubic  Yards. 
.  0.44 

0.45 

046 

0.48 

MATERIALS.- 


Gravel  or  Stone. 
Cubic  Yards, 
0.88 
0.91 

0.93 
0.96 

-The  above  table 


'Concrete,  Plain  and  Reinforced."     Taylor  &  Thompson. 


CONCRETES. 


597 


is  made  from  the  formulas  devised  by  William  B.  Fuller  for  deter- 
mining the  quantities  of  materials  for  one  cubic  yard  of  Portland 
cement  concrete  of  dififercnt  proportions  of  cement,  sand  and  gravel 
or  stone.  (See  Article  499,  Proportions  of  Materials  for  these  same 
mixtures.) 

In  the  table,  and  in  the  proportions,  a  barrel  of  Portland  cement 
is  taken  at  376  pounds,  equal  to  4  bags  and  as  ''packed  ;"  a  barrel 
of  loose  sand  is  taken  equal  to  3.8  cubic  feet ;  and  a  barrel  of 
loose  gravel  or  stone  at  3.8  cubic  feet. 

501.  MIXING  THE  CONCRETE.— Concrete  may  be  made 
either  by  machine-mixing  or  by  hand.  The  quantity  to  be  laid  and 
the  relative  cost  of  the  two  methods  determine  the  advisability  of 
employing  one  or  the  other  method,  and  the  relative  cost  depends 
upon  circumstances  and  has  to  be  estimated  for  each  individual  case. 

Mixing  by  Machinery— On  large  contracts  machinery  is  univer- 
t>ally  replacing  hand  labor.  Concrete  mixers  may  be  classified  under 
two  general  heads:  (  i)  continuous  mixers,  into  which  the  materials 
are  constantly  fed,  generally  by  shovelfuls,  the  concrete  discharging 
in  a  steady  stream,  and  (2)  batcji  mixers,  which  receive  in  one 
charge  a  certain  large  amount,  such  as  a  barrel  of  cement  or  a 
bag  of  cement  and  the  accompanying  proportionate  volume  of  sand 
and  stone,  and  which,  after  the  mixing,  discharge  the  cement  in 
-one  mass. 

Again,  concrete  mixers  may  be  classified  into  three  general  types : 
(i)  rotating  mixers,  (2)  paddle  mixers  and  (3)  gravity  mixers,  all 
depending  upon  the  manner  in  which  the  mixing  process  is  accom- 
plished. 

Mixing  by  Hand. — The  most  satisfactory  method  of  mixing  con- 
crete by  hand  is  to  first  prepare  a  tight  floor  of  plank,  or  better  still, 
of  sheet-iron  with  the  edges  turned  up  about  2  inches,, to  hold  the 
mixture. 

Upon  this  platform  the  sand  should  be  spread  first,  and  the  cement 
should  be  spread  over  the  sand.  The  two  should  then  be  thoroughly 
and  immediately  mixed  by  means  of  shovels  or  hoes,  the  broken 
stone  or  aggregate  then  dumped  on  top  and  the  whole  worked 
over  with  shovels  first,  while  dry  and  afterward,  a  second  time, 
while  water  is  added  from  a  sprinkler  on  the  end  of  a  hose.  After 
enough  water  has  been  added,  the  mass  should  be  again  worked 
over  at  least  twice.    For  a  moderately  dry  mixture  only  as  much 


598 


BUILDING  CONSTRUCTION.  (Ch.  X) 


water  is  added  as  is  necessary  to  enable  the  mortar  to  completely 
coat  and  cause  to  adhere  all  the  particles  of  the  aggregate,  so  that 
when  the  concrete  is  tamped  the  water  will  just  flush  to  the  surface 
without  much  quaking.    (See  also  Article  502.) 

The  water  used  should  be  clean  and  at  about  the  temperature 
of  65°  Fahr. 

502.  PLACING  OR  DEPOSITING  CONCRETE.— Concrete 
is  usually  deposited  in  layers  from  6  to  10  inches  thick,  and  should 
be  carefully  put  in  place  so  that  the  materials  will  not  separate.  It 
may  be  wheeled  in  barrows  immediately  after  mixing,  and  gently 
tipped  or  slid  into  position  and  at  once  rammed  before  the  cement 
begins  to  set,  the  ramming  or  tamping  being  continued  until  the 
water  begins  to  ooze  out  upon  the  surface.  Square  wooden  ram- 
mers measuring  from  6  to  8  inches  on  a  side,  or  round  ones  from 
8  to  12  inches  in  diameter  and  weighing  between  10  and  20  pounds, 
are  generally  used.  In  a  dry  or  jelly-like  mixture  the  mass  should 
be  rammed  until  the  mortar  flushes  to  the  surface,  while  for  a 
wet  concrete  the  mass  should  be  merely  puddled  or  "joggled"  to 
expel  the  air  and  the  surplus  water.    (See  also  Article  501.) 

Whenever  possible,  sections  of  concrete  work  should  be  carried 
on  continuously  until  completed,  in  order  to  avoid  lines  of  cleavage ; 
but  when  the  depositing  must  be  done  in  layers,  before  beginning 
the  work  anew,  the  surfaces  should  be  cleaned,  roughened  and  wet, 
or  washed  with  a  neat  cement  paste  or  grout  having  the  consistency 
of  cream.  It  is  now  recognized  that  for  the  strongest  construction 
and  for  water-tight  work,  concrete  should  be  as  nearly  as  possible 
one  single  solid  mass  with  no  joints;  and  to  accomplish  this  result 
the  concrete  is  made  to  have  a  ''quaking,"  jelly-like  consistency,  or 
even  made  with  enough  water  to  be  "mushy"  or  "sloppy." 

503.  THE  STRENGTH  OF  CONCRETE.— The  following 
conditions  determine  the  strength  of  concrete:  (i)  the  quality  of 
the  materials,  (2)  the  quantity  of  cement  in  a  cubic  yard  of  the  con- 
crete and  (3)  the  density  of  the  mixture. 

The  average  ultimate  crushing  strength  of  natural  cement  con- 
crete of  the  usual  average  materials,  one  year  old,  is  about  800 
pounds  per  square  inch ;  that  of  a  i  to  2  to  4  Portland  cement  con- 
crete is  from  2,000  to  2,200  pounds  per  square  inch  and  that  of  a 
I  to  3  to  6  Portland  cement  concrete  is  from  1,600  to  1,800  pounds 


CONCRETES. 


599 


per  square  inch.  These  are  average  values  for  reasonably  good 
conditions  as  to  character  of  materials  and  workmanship. 

The  tensile  strength  of  concrete  is  very  much  less  than  the  com- 
pressive strength,  but  it  cannot  be  accurately  given.  When  the  con- 
crete is  made  with  care  it  is  probably  safe  to  say  that  its  strength 
per  square  inch  will  be  from  one-tenth  to  one-eighth  of  its  com- 
pressive strength,  although  there  is  no  fixed  relation  between  the 
two  values. 

TABLE  XXXI. 

Compressive   and   Tensile   Strength   of   Portland  Cement 
Concretes  Compared. 
Tests  by  Professor  W.  K.  Hatt  gave  the  following  results : 

Age,        Comp.  Strength,  Tens.  Strength, 
Kind  of  Concrete.  days.  lbs.  per  sq.  in.       lbs.  per  sq.  in. 


2:4  (broken  stone)  30    311 

2:5  (broken  stone)  90  2413  359 

2:5  (broken  stone)  28  2290  237 

5  (gravel)   90  2804  290 

5  (gravel)   28  2400  253 


Regarding  the  ultimate  flexural  fiber  stress  or  modulus  of  rup- 
ture, for  Portland  cement  concrete,  it  is  from  one  and  one-half  times 
to  twice  the  ultimate  direct  tensile  stress,  or  from  one-seventh  to 
one-fifth  the  direct  crushing  strength. 

Using  experimental  crushing  tests  as  a  basis,  the  safe  working 
loads  for  concrete  may  be  assumed  to  range  from  one-third  to 
one-tenth  of  the  breaking  loads,  depending  upon  various  conditions. 

The  following  table  gives  the  safe  strength  of  Portland  cement 
concrete  in  direct  compression,  based  upon  conservative  practice: 

TABLE  XXXn. 
Safe  Strength  of  Portland  Cement  Concretes  in  Direct 

Compression. 

Pounds  per  Tons  per 

Proportions.                                       '     square  inch.  square  foot, 

1:2  :    4                                                     410  29 

1 :5                                                   360  25 

i-3'    6                                                    325  23 

1:4:    8                                                  260  18 

These  figures  allow  a  factor  of  safety  of  six  at  the  age  of  one 
month,  or  of  eight  at  the  age  of  six  months.    For  a  large  mass  foun- 


4 


6oo  BUILDING  CONSTRUCTION.  (Ch.  X) 

dation,  values  one-eighth  greater  may  be  taken,  and  for  vibrating- 
or  pounding  loads,  values  one-half  of  those  given. 

For  a  varying  character  of  pressure,  the  safe  compressive  strength 
of  Portland  cement,  stone  or  gravel,  concrete  may  be  taken  as  fol- 
lows, and  fairly  represents  modern  practice : 

TABLE  XXXIII. 
Safe  Compressive  Strength  of  Portland  Cement  Concrete 
FOR  Varying  Character  of  Pressure. 

Safe  strength  at  i  month 
of  1 :2>^  :5  mixture. 
Character  of  Pressure.  Lbs.  per  sq.in.  Tons  per  sq.  in. 

Direct  compression  on  mass  concrete   400  29 

Compressive  stress  in  reinforced  beams   625  45 

Columns  over  2  square  feet  in  sectional  area   350  25 

Columns  under  2  square  feet  in  sectional  area. .  . .  300  22 
Bearing  of  iron  on  concrete,  such  as  bridge  seats.  400  29 
Cinder  concrete  in  direct  compression   150  11 

When  mass  concrete  or  piers  are  subjected  to  vibrating  or  pound- 
ing loads,  the  factors  of  safety  may  be  nearly  doubled,  and  the  work- 
ing values  given  thus  made  very  much  lower. 

The  modulus  of  elasticity  of  concrete  varies  from  1,500,000  to 
5,000,000  pounds  per  square  inch.  For  ordinary  mixtures  of  Port- 
land cement  concrete  a  general  average  value  of  2,500,000  is 
sufficiently  close  for  all  practical  purposes. 

Some  authorities  give  for  the  average  ultimate  shearing  strength 
of  concrete,  for  'Vertical  shear,"  as  deduced  from  theory  and  tests, 
almost  one-half  the  strength  in  direct  compression/'^'  Shear  here 
denotes  the  strength  of  the  material  against  a  sliding  failure  when 
tested  as  a  rivet  or  bolt  would  be  tested  for  shear.  This  does  not 
refer  to  the  complex  action  which  occurs  in  the  web  of  a  beam, 
where  there  exist  direct  tensile  and  compressive  stresses  which  at 
the  neutral  axis  are  equal  in  intensity  to  the  vertical  and  horizontal 
shearing  stresses.  When  ''diagonal  tension"  is  treated  as  shear, 
the  strength  should  be  very  nearly  the  same  as  the  tensile  strength 
of  the  material  determined  in  the  usual  way.  The  subject  of 
shearing  strength  of  concrete  needs  much  more  careful  experi- 
mental study.  There  is  not  a  great  deal  of  definite  knowledge 
on  the  subject.    The  results  of  tests  by  French  and  German  authori- 


*  From  data  on  experiments  on  direct  shear  in  concrete  conducted  by  Prof.  Charles. 
]\T.  Spotford  at  the  Massachusetts  Institute  of  Technology,  and  by  Professor  Arthur  N. 
Talbot  at  the  University  of  Illinois. 


CONCRETES. 


6or 


ties  give  much  lower  values  than  those  of  recent  tests  in  the  United 
States.    Some  tests  show  vertical  shear  twice  the  tensile  strength. 

The  elastic  limit  in  compression  is  about  600,  or  600,  but  it  is 
sometimes  assumed  to  be  one-half  or  two-thirds  the  ultimate  strength. 

When  used  in  reinforced  Portland  cement  concrete  work,  the  fol- 
lowing are  safe  average  unit  stresses,  in  pounds  per  square  inch,  for 
the  concrete,  as  recommended  by  good  authorities.  The  factor  of 
safety  and  coefficient  of  expansion  are  also  given  in  addition  to  the 
stresses : 

TABLE  XXXIV. 
Safe  Average  Unit  Stresses  for  Reinforced  Portland  Cement 

Concrete  Work.  conckete1:2:4 

Factor  of  safety  c-   5 

Direct  compression   350  to  500 

Compression  fibers  in  a  beam   500  to  700 

Direct  tension   50 

Diagonal  tension  in  a  beam  50  to  75 

Tension  fibers  in  a  beam  (when  tension  is  considered)  75 

Modulus  of  elasticity   2,500,000 

Vertical  shear   175 

Coefficient  of  expansion   0.0000064 

Adhesion  of  cement  mortar  to  steel   50  to  75 

Ratio  of  moduluses  of  elasticity  of  concrete  to  steel   1  to  12 

It  will  be  understood  that  these  are  only  average  stresses,  and 
will  vary  according  to  the  kind  of  cement  used,  the  nature  of  the 
aggregate  and  many  other  varying  conditions.  Various  model  and 
standard  specifications  are  being  issued,  and  many  cities  have  definite 
requirements  in  their  building  laws  which  fix  the  stresses  to  be  used. 

The  value  3,000,000  pounds  per  square  inch  for  the  modulus  of 
elasticity  has  been  used.  As  very  recently  established  by  experi- 
ment, 2,500,000  is  found  to  more  nearly  represent  the  correct  aver- 
age value. 

The  foregoing  values  have  been  used  for  stone  or  gravel  con- 
cretes. In  the  following  table  there  are  given  the  ultimate  compres- 
sive strength  and  the  modulus  of  elasticity  of  cinder  concretes, 
taken  from  the  Watertown  Arsenal  Tests  of  il 


TABLE  XXXV. 
Compressive  Strength  and  Modulus  of  Elasticity  of  Cinder; 

Concrete. 


Mixture, 

Average  Crushing  Strength. 
Pounds  Per  Square  Inch. 

Average  Modulus  of 
Elasticity  Between 
Loads  of  100  and  600 
Pounds  Per  Square 
Inch. 

Cement.  Cinders. 

Sand. 

One  Month. 

Three  Months. 

1  1 

3 

1,540 

2,050 

2,540,000 

1  2 

3 

1,098 

1,634 

1  2 

4 

904 

1.325 

1  2 

5 

724 

1,094 

1,040,000 

1  3 

6 

529 

788 

'602 


BUILDING  CONSTRUCTION.  (Ch.  X) 


504.  CONTRACTION  AND  EXPANSION  IN  HARDEN- 
ING.— To  determine  the  shrinkage  and  swelHng  of  cement  mortars 
in  hardening  many  experiments  have  been  made,  and  the  results 
indicate  that  when  they  set  in  the  air  they  contract  sHghtly  and 
when  they  set  in  water  they  are  Hkely  to  expand. 

The  amount  of  change  in  dimensions  seems  to  vary  directly  with 
the  richness  of  the  mortar  or  cement,  and  the  shrinkage  of  concrete 
seems  generally  to  be  less  than  that  of  mortar  and  approximately 
proportional  to  the  amount  of  cement  per  unit  volume,  the  sand  and 
stone  being  unaffected. 

When  there  is  no  reinforcement,  shrinkage  cracks  are  apt  to 
appear  in  the  finished  work,  and  to  prevent  them  the  concrete  is  kept 
moistened  for  a  while  after  being  put  in  place. 

Experiments  have  shown  a  .05  to  .15  per  cent  shrinkage  in  a  I  to  3 
mortar,  hardened  in  air  for  from  2  to  4  months,  and  only  a  .01 
per  cent  shrinkage  in  the  same  mortar  reinforced  with  5^  per 
cent  of  steel;  and  the  shrinkage  is  still  less  for  reinforced  concrete. 

505.  LAYING  CONCRETE  IN  FREEZING  WEATHER— 
Various  forms  of  clauses  are  used  in  specifications  for  concrete  deal- 
ing with  the  question  of  the  effect  of  frost  upon  the  materials  used. 
For  example,  the  clause  may  read,  "No  concrete  shall  be  laid  in 
freezing  weather  except  by  special  arrangement  with  and  under  the 
supervision  of  the  architect  or  engineer  in  charge  of  the  work. 
Should  it  be  necessary  to  put  it  in  place  in  such  weather,  special 
arrangements  must  be  made  for  heating  all  the  ingredients  of  the 
mixtures,  and  for  maintaining  a  temperature  which  will  not  allow  the 
concrete  to  freeze  until  it  has  properly  set." 

Or  again,  the  clause  may  read,  ''No  concrete  shall  be  exposed  to 
frost  until  hard  and  dry,  except  that  laid  in  large  masses,  or  in 
heavy  walls  having  faces  whose  appearance  is  of  no  consequence. 
No  materials  used  in  mass  concrete  laid  in  freezing  weather  shall 
contain  any  frost.  All  surfaces  shall  be  protected  from  frost,  and 
all  parts  of  surface  concrete  which  have  frozen  shall  be  removed 
before  fresh  concrete  is  laid  upon  them." 

A  good  general  rule  is  to  avoid  laying  concrete  of  any  kind  in 
freezing  weather,  unless  it  is  really  necessary  to  do  so.  When, 
however,  circumstances  make  it  necessary,  and  when  they  warrant 
the  extra  expense,  mass  concrete,  if  made  of  Portland  cement,  may 


CONCRETES. 


603 


be  laid  at  almost  any  temperature,  provided  proper  precaution  is 
taken  and  careful  inspection  guaranteed. 

Natural  cement  concrete  should  never  be  exposed  to  frost  until 
thoroughly  hard  and  dry. 

There  is  considerable  difference  of  opinion  among  American 
engineers  regarding  the  injury  to  Portland  cement  concrete  from 
freezing,  or  from  alternate  freezing  and  thawing;  but  as  there  are 
many  examples  of  concrete  construction  which  show  serious  injury 
from  freezing,  it  would  seem  advisable,  at  least  in  the  case  of  rein- 
forced concrete  construction,  to  lay  it  only  when  the  temperature  is 
above  the  freezing  point. 

The  clause  relating  to  this  in  the  ''Regulations  of  the  Bureau  of 
Building  Inspection  of  the  City  of  Philadelphia"  in  regard  to  'The 
Use  of  Reinforced  Concrete,"  and  a  part  of  the  revised  building  laws 
and  ordinances  of  1907,  is  as  follows :  "Concrete  shall  not  be  mixed 
•or  deposited  in  freezing  weather,  unless  precautions  are  taken  to 
avoid  the  use  of  material  covered  with  ice  or  snow  or  that  are  in 
any  other  way  unfit  for  use,  and  that  further  precautions  are  taken 
to  prevent  the  concrete  from  freezing  after  being  put  in  place.  All 
forms  under  concrete  so  placed  to  remain  until  all  evidences  of  frost 
are  absent  from  the  concrete^and  the  natural  hardening  of  the  con- 
crete has  proceeded  to  the  point  of  safety." 

506.  EFFECT  OF  SEA  WATER  UPON  CONCRETES  AND 
MORTARS. — Sea  water  has  a  decomposing  action  on  all  cements, 
concretes  and  other  hydraulic  products.  The  following  is  a  sum- 
mary of  the  principal  conclusions  reached  by  investigations  of  this 
subject,  and  notably  by  Monsieur  R.  Feret: 

(1)  The  most  injurious  compounds  in  sea  water  are  the  sulphates. 

(2)  Portland  cements  used  for  concretes  in  sea  water  should  have 
a  low  percentage  of  aluminum  and  lime. 

(3)  When  gypsum  is  used  to  regulate  the  time  of  setting,  only 
the  smallest  possible  quantity  should  be  added. 

(4)  Puzzolanic  material  has  proved  a  valuable  addition  for  mor- 
tars and  concretes  used  in  sea-water  construction. 

(5)  Fine  sand  should  never  be  used. 

(6)  The  essential  qualities  for  mortars  and  concretes  used  in  sea- 
water  constructions  are  density  and  imperviousness. 

507.  THE  FIRE-RESISTING  PROPERTIES  OF  CON- 
CRETE.— A  great  many  tests  have  been  made 'to  determine  the  fire- 


6o4 


BUILDING  CONSTRUCTION.  (Ch.  X) 


proofing  qualities  or  fire-resisting  properties  of  cement  concretes, 
and  much  has  been  written  on  the  subject.  Laboratory  tests  have 
been  supplemented  by  the  natural  tests  of  unexpected  large  con- 
flagrations, and  something  learned  from  each. 

When  stone  concrete  is  subjected  to  great  heat  the  outer  surfaces 
expand,  leaving  the  under  parts  comparatively  unaffected,  with  the 
exception  of  some  slight  cracking  or  of  a  tendency  to  warp.  This 
is  because  the  concrete  is  a  very  poor  conductor  of  heat.  About  an 
inch  of  the  outside  portion  of  the  concrete  mass  also  tends  to  dis- 
integrate from  the  action  of  the  heat,  the  strength  and  texture  are 
affected  unfavorably  and  there  is  frequently  a  spalling  off  of  the 
surface.  Sudden  application  of  water  at  this  time  causes  a  washing 
away  of  the  portions  thus  affected. 

The  relative  resisting  qualities  of  concrete  made  from  cinder, 
stone  (trap  rock)  and  slag  are  usually  taken  in  the  order  named. 
Limestones  used  in  the  aggregate  tend  to  calcine  under  the  action 
of  the  heat  and  to  be  thus  destroyed  if  subjected  to  water,  while 
gravel  and  granite  used  as  part  of  the  aggregate  tend  to  spall 
because  of  the  difference  between  their  coefficient  in  expansion  and 
that  of  the  rest  of  the  concrete  mass. 

In  regard  to  reinforced  concrete  as  a  fire-resisting  construction,, 
it  is  reasonable  to  believe  that,  in  view  of  the  results  obtained  from 
recent  tests  and  conflagrations,  it  should  prove  to  be  satisfactory. 
Severe  tests  have  been  made  for  beams,  floor  slabs  and  columns, 
using  different  systems  of  reinforcing.  Some  systems  and  mixtures 
have  stood  the  tests,  and  some  have  failed,  those  failing  usually 
owing  their  failure  to  such  causes  as  insufficiently  dried-out  concrete,, 
insufficient  thickness  of  concrete  over  the  metal,  the  use  of  broken 
Stone  containing  a  high  percentage  of  lime,  etc. 

508.  COST  OF  CONCRETE.— The  first  cost  of  the  material 
does  not  control  the  total  cost  of  the  concrete  as  much  as  does  the 
general  character  of  the  construction  with  the  varying  conditions 
accompanying  it.  . 

When  the  cost  of  the  forms  is  relatively  small,  and  when  the  con- 
crete is  laid  in  large  masses,  from  $4  to  $7  per  cubic  yard  in  place 
may  be  taken  as  the  average  limits  of  cost.  If  the  conditions  are 
favorable,  if  the  prices  charged  for  the  materials  are  low  and  if  the 
work  is  done  by  contract,  the  lower  amount  mentioned  may  be  con- 
sidered a  fairly  average  cost ;  while  if  the  operation  is  a  small  one, 


CONCRETES.  605. 

and  if  the  workmen  are  inexperienced,  the  cost  may  run  up  to  the 
higher  h'mit. 

In  work  which  is  not  of  such  a  simple  nature,  and  in  which  cen- 
tering is  required,  as,  for  example,  in  arch  construction,  the  limits 
may  be  raised  to  from  $7  to  $14  per  cubic  yard. 

The  cost  may  be  increased  still  more  in  other  kinds  of  concrete 
work  to  from  $10  to  $20  per  cubic  yard,  according  to  the  character 
of  the  construction  and  the  treatment  of  the  surfaces  or  faces.  Cer- 
tain relatively  thin  walls  of  buildings  come  under  this  head. 

Such  a  great  variation  or  range  in  price,  from  $4  to  $24  per  cubic 
yard,  is  explained  by  the  fact  that  there  is  just  as  great  a  range  in 
the  conditions  obtaining,  due  to  the  magnitude  of  the  operations 
and  to  the  character  of  the  work,  which  also  depends  in  turn  upon 
the  kind  of  labor  and  materials  employed. 

When  all  the  conditions  are  known  ir^  advance,  it  is  possible  to 
make  a  very  close  estimate  of  the  cost  of  concrete  put  in  place,  by 
estimating  in  detail  the  cost  of  each  unit  entering  into  the  finished 
mixture,  such  as  the  cement,  the  sand,  the  gravel  or  broken  stone 
and  the  labor,  and  then  by  combining  the  different  unit  costs. 

The  cost  of  cement  varies  largely  with  the  demand.  The  cost  of 
sand  depends  chiefly  upon  the  distance  it  is  hauled  and  upon  the  cost 
of  screening.  Variations  in  the  cost  of  gravel  and  broken  stone  also 
depend  largely  upon  the  hauling,  and,  in  the  case  of  gravel,  upon 
the  cost  of  screening  also.  The  cost  of  labor  in  mixing,  rnoving  and 
depositing  the  concrete  depends  upon  the  methods  employed  and 
upon  the  extent  to  which  the  labor  may  be  called  skilled  or  experi- 
enced. The  cost  of  the  labor  on  forms  varies  between  wide  limits^ 
and  depends  upon  the  character  of  the  concrete  work,  such  as  the 
'  thicknesses  of  walls,  the  extent  of  face  areas,  the  amount  of  rein- 
forcing, etc. 

Close  estimates  of  the  cost  of  the  units,  as  outlined  above,  are  now 
available,  and  may  be  found  worked  out  in  great  detail  in  the  various 
treatises  on  concrete  construction.  After  determining  the  cost  of 
each  ingredient  per  unit  used,  such  as  the  cement,  sand  and  gravel 
or  broken  stone,  and  knowing  the  proportions  of  the  mixture,  the 
cost  of  each  unit  per  cubic  yard  of  concrete  may  be  found  from  the 
table  given  in  Article  500,  "Quantities  of  Materials ;"  and  by  com- 


6o6  BUILDING  COX STRUCTION .  (Ch.  X) 

billing  these  costs  and  adding  the  cost  of  labor  per  cubic  yard  the 
cost  per  cubic  yard  of  the  concrete  put  in  place  may  be  found.* 

509.  WEIGHT  OF  PORTLAND  CEMENT  CONCRETE.— 
The  character  of  the  materials,  the  degree  of  their  compactness, 
their  specific  gravity  and  the  proportions  in  which  they  are  used 
affect  the  weight  of  concrete  as  well  as  that  of  mortar.  Average 
weights  may  be  taken  as  follows  for  Portland  cement  concretes : 

Cinder  Concrete    112  lbs.  per  cu.  ft. 

Sandstone  Concrete    143    "     "  *' 

Limestone  Concrete    148    "     "     "  " 

Conglomerate  Concrete    150    "     "    "  " 

Gravel  Concrete    150   "     "    "  " 

Trap  Concrete    155    "     "    "  " 

For  practical  purposes  an  average  value  of  145  pounds  per  cubic 
feet  may  be  taken.  The  addition  of  reinforcing  steel  in  the  custom- 
ary proportions  usually  adds  from  3  to  5  pounds  per  cubic  foot,  so 
that  the  weight  of  reinforced  concrete  may  be  taken  at  150  pounds 
per  cubic  foot. 

510.  MISCELLANEOUS  DATA  ON  HANDLING  CON- 
CRETE-— The  following  valuable  and  useful  data  bearing  upon  this' 
part  of  the  subject  have  been  compiled  and  condensed  by  Taylor  & 
Thompson.  They  form  part  of  a  summary  of  general  concrete 
data  in  their  treatises  on  concrete  and  are  reproduced  here  by  per- 
mission : 

TABLE  XXXVI. 

Miscellaneous  Data  ox  Handling  Concrete. 

Average  load  of  broken  stone  or  gravel  for  wood  wheelbarrow...    2.4  cu.  ft. 

Average  load  of  sand  for  wood  wheelbarrow   2.5  " 

Large  load  of  broken  stone  or  gravel  for  iron  wheelbarrow  on 

short  haul  in  concrete  work   3.0  "  " 

Large  load  of  sand  for  iron  wheelbarrow  on  short  haul  in  con- 
crete work    3.5 

Average  load  of  ordinary  concretef  for  iron  wheelbarrow   1.9 

Large  load  of  ordinary  concrete  for  iron  wheelbarrow   2.2  " 

Number  of  shovelfuls  of  concrete  per  barrow  in  average  load....  13 

Number  of  shovelfuls  of  concrete  per  barrow  in  large  load   15 

Average  net  time  of  one  man  filling  wheelbarrow  with  concrete...    15^  min. 

*  See  also  the  "Arcliitect's  and  Builder's  rocket-Book."  F.  E.  Kidder.  Chapter  III, 
•**Cost  of  Concrete  and  Materials  Required  per  Yard." 

hee  also  for  detailed  estimates  of  cost  of  units  of  concrete  and  labor  for  same, 
"Concrete,  Plain  and  Reinforced."  Taylor  &  Thompson.  Chapter  II,  "Approximate 
Cost  of  Concrete."  ,       ,  r  .       •       ,  f» 

t  All  measurements  of  concrete  are  reduced  to  terms  of  quantity  in  place  after 
j-amming. 


.  .  CONCRETES.    .  607 

Quick  net  time  of  one  man  filling  wheelbarrow  with  concrete   i  min. 

Average  quantity  of  concrete*  mixed,  wheeled  50  ft.  and  rammed, 

per  man,  per  day  of  10  hoursf   2.2  cu.  yds^ 

Large  quantity  of  concrete*  mixed,  wheeled  50  ft.  and  rammed, 

per  man,  per  day  of  10  hoursf   3 

Average  quantity  of  concrete*  laid  as  above  with  a  gang  of  15 

men  per  day  of  10  hoursf   33 

Large  quantity  of  concrete*  laid  as  above  with  a  gang  of  15  men 

per  day  of  10  hoursf   47 

Approximate  average  quantity  of  concrete*  levelled  and  rammed, 

in  6-inch  layers,  per  man,  per  day  of  10  hours   11  " 

Approximate  large  quantity  of  concrete*  levelled  and  rammed, 

in  6-inch  layers,  per  man,  per  day  of  10  hours   16 

Approximate  average  surface  of  rough  braced  plank  forms  built 

and  removed  by  one  carpenter  per  day  of  10  hours   25  sq.  yds-> 


511.  EXAMPLES  OF  PORTLAND  CEMENT  CONCRETE. 
— Foundations  of  Mutual  Life  Insurance  Company's  btiilding-,  N'ewT 
York :    t  part  cement,  3  parts  sand,  5  parts  broken  stone. 

Foundations  of  United  States  Naval  Observatory,  Georgetown,, 
D.  C. :  ■  I  part  cement,  parts  sand,  3  parts  gravel,  5  parts 
broken  stone,  [i  barrel  of  cement,  380  pounds,  made  1.18  yards 
of  concrete.] 

Foundations  of  Cathedral  of  St.  John  the  Divine,  New  York. 
Proportions :  I  part  Portland  cement,  2  parts  sand,  3  parts  quartz- 
gravel,  to  2  inches  in  diameter.  [17,000  barrels  of  cement  made 
11,000  yards  of  concrete.] 

Filling  of  caissons,  Johnston  building  (fifteen  stories),  New  York: 

1  part  Portland  cement,  3  parts  sand,  7  parts  stone,  finished  on  top> 
for  brickwork  with  i  part  cement  and  3  parts  gravel. 

Manhattan  Life  Insurance  Company's  building,  New  York,  filling- 
of  caissons:  i  part  Alsen's  Portland  cement,  2  parts  sand,  4  parts, 
broken  stone. 

Professor  Ira  O.  Baker  states  that  the  concrete  foundations  under 
the  Washington  Monument  were  made  of  i  part  Portland  cement,, 

2  parts  sand,  3  parts  gravel  and  4  parts  broken  stone,  and  that  this 
mixture  stood,  at  six  months  old,  a  load  of  2,000  pounds  per  square 
inch,  or  144  tons  per  square  foot. 

512.  SPECIFICATIONS  FOR  CONCRETES.— Numerous 
specifications  have  been  prepared  and  published  for  dififerent  kinds 

*  All  measurements  of  concrete  are  reduced  to  terms  of  quantity  in  place  after 
ramming. 

t  Note  that  the  levelling  and  ramming,  but  not  the  labor  on  forms,  are  included  in 
this  item. 


6o8 


BUILDING  CONSTRUCTION.  (Ch.  X) 


of  concrete  by  many  communities,  societies,  engineers,  authors  of 
treatises  on  cements  and  concretes,  building  departments,  etc.,  both 
for  mass  concrete  and  for  reinforced  concrete.  They  represent  the 
latest  standard  practice,  and  those  for  reinforced  work  include  also 
the  specifications  for  first-class  or  high  steel  with  recommendations 
made  to  safely  adapt  this  important  material  to  reinforced  concrete 
construction. 

It  is  not  possible  in  this  condensed  hand-book  to  reproduce  these 
various  specifications.  For  the  proportions  of  materials  for  average 
conditions  the  reader  is  referred  to  Article  499  and  for  some  brief 
.specification  forms  to  Chapter  XIII,  "Specifications." 

513.  CLASSES  OF  CONCRETE  CONSTRUCTION.— When 
applied  to  building  construction,  concrete  work  may  be  classified 
under  three  general  heads : 

Mass  or  Massive  Concrete  Construction,  which  is  without  any 
metal  reinforcing  materials,  or  which  has  so  little  reinforcement 
.that  the  tensile  stresses  are  very  slightly  resisted. 

Reinforced  Concrete  Construction,  which  has  metal  reinforcing 
materials  arranged  to  fully  resist  the  tensile  stresses,  and  when 
necessary  arranged  also  to  partially  resist  the  compressive  and 
shearing  stresses  developed. 

Concrete  Block  Construction,  which  consists  of  concrete ,  wall 
blocks,  molded  or  cast  in  various  forms,  and  which  includes  also 
facings,  ornaments,  sills,  caps,  lintels,  etc.,  molded  or  cast  from 
concrete. 

2.    MASS  CONCRETE  CONSTRUCTION. 

514.  EARLY  EXAMPLES  AND  USES  OF  MASS  CON- 
CRETE.— A  brief  description  of  mass  concrete  has  been  given  in 
the  definition.  It  is  used  principally  in  the  construction  of  footings, 
supporting  walls  below  and  above  grade,  cores  of  walls,  retaining- 
walls,  reservoir  walls,  breakwaters,  dikes,  piers,  heavy  columns, 
machinery  supports,  sidewalks,  arches,  domes  and  many  other  con- 
structions in  which  a  heavy  mass  is  the  prime  requisite.  Concrete 
composed  of  broken  stone,  fragments  of  brick,  pottery,  gravel  and 
sand,  held  together  by  being  mixed  with  lime,  cement,  asphaltum  or 
other  binding  substances,  has  been  used  in  construction  for  many 
ages  to  resist  compressive  stress. 

The  Romans  used  it  more  extensively  than  any  other  material,  as 


CONCRETE  CONSTRUCTION. 


609 


the  great  masses  of  concrete  once  the  foundations  of  large  temples, 
palaces  and  baths,  the  domes,  arches  and  vaultings  still  existing, 
together  with  the  cores  or  interior  portions  of  nearly  all  the  ancient 
brick-faced  walls  found  in  Rome,  testify. 

In  France,  in  the  forest  of  Fontainebleau,  there  are  three  miles 
of  continuous  arches,  some  of  them  fifty  feet  high,  part  of  an 
aqueduct  constructed  of  concrete  and  formed  in  a  single  structure 
without  joint  or  seam.  A  Gothic  church  at  Vezinet,  near  Paris, 
which  has  a  spire  130  feet  high,  is  a  monolith  of  concrete.  The 
lighthouse  at  Port  Said,  Egypt,  is  another  monolithic  structure,  180 
feet  in  height. 

The  breakwaters  at  Port  Said,  Marseilles,  Dover  and  other  impor- 
tant ports  are  formed  of  immense  blocks  of  concrete.  The  water 
pipes  and  aqueduct  at  Nice,  and  the  Paris  sewers,  are  also  notable 
constructions  of  the  same  material. 

In  England  and  France  thousands  of  dwellings  have  been  built 
of  concrete,  in  place  of  brick  and  stone.  Many  of  these  are  now 
standing,  and  some  have  stood  for  almost  a  century,  without  the 
least  sign  of  decay.  In  the  United  States,  until  quite  recently,  the 
number  of  concrete  buildings  was  comparatively  small. 

The  architects,  engineers  and  capitalists  of  the  United  States 
appeared  for  a  long  time  to  be  more  timid  than  those  of  any  other 
nation  in  availing  themselves  of  the  use  of  concrete  as  a  building 
material;  and  it  is  only  since  the  year  1885  that  it  has  been  used  to 
any  extent  in  this  country  in  the  construction  of  buildings  except 
for  the  footings  of  foundation  walls. 

Suitable  materials  for  making  concrete  are  available  in  almost 
every  locality,  and  in  most  places  solid  walls  of  concrete  are 
cheaper  and  more  enduring  than  those  of  brick  or  stone. 

For  many  years  perhaps  the  best  known  of  all  concrete  buildings 
in  the  United  States  were  the  hotels  Ponce  de  Leon  and  Alcazar,  at 
St.  Augustine,  Florida,  Messrs.  Carrere  &  Hastings,  architects. 

These  buildings,  composed  entirely  of  concrete,  presented  an 
early  example  in  this  country  of  the  almost  limitless  use  to  which 
concrete  can  be  put. 

For  the  construction  of  these  hotels  an  elevator,  was  built  at  a 
central  point  of  the  operation,  to  the  full  height  of  the  intended 
buildings,  and  as  the  walls  progressed,  story  upon  story,  runways 
were  made  to- each  floor,  and  the  concrete,  mixed  by  two  capacious 


6io 


BUILDING  CONSTRUCTION, 


(Ch.  X) 


mixing  machines  on  the  ground  level,  was  lifted  in  barrels  and  run 
off  to  the  place  of  deposit,  enormous  quantities  of  cement  being 
used  in  the  concrete  in  a  single  day. 

The  time  transpiring  between  the  wetting  of  the  concrete  and  the 
final  running  in  place,  even  at  the  fifth  story,  was  not  more  than  ten 
minutes  at  any  time. 

The  concrete  was  composed  of  i  part  of  imported  Portland 
cement,  2  parts  of  sand  and  3  parts  of  coquina,  the  greater  part 
passing  through  a  ^-inch  mesh. 

The  cost  of  the  concrete  in  place  was  about  $8  a  yard,  including 
arches,  columns,  etc.  In  plain  thick  walls  the  cost  was  often  much 
less. 

In  the  basement  of  the  Alcazar  is  a  bathing  pool  100  feet  long,  60 
feet  wide  and  from  3  to  10  feet  deep,  all  made  of  concrete.  Rising 
from  this  pool  are  concrete  columns,  6  feet  square  at  the  base  and 
40  feet  high.  They  support  concrete  beams  of  25  feet  span,  hol- 
lowed out  in  arch  form  and  supporting  the  glazed  roof  covering 
,    the  interior  court. 

515.  MATERIALS  USED  IN  MASS  CONCRETE  CON- 
STRUCTION AND  THEIR  PROPORTIONS.— These  have  been 
considered  in  Articles  498,  499  and  500,  in  the  discussion  of  con- 
cretes in  general. 

A  good  average  mixture  for  use  in  mass  concrete  construction  is 
composed  of  i  part  of  Portland  cement,  3  parts  of  sand  and  6  parts 
of  broken  stone. 

For  concrete  mass  work  under  ground  and  away  from  the  action 
of  the  atmosphere,  a  puzzolan  cement  may  be  used ;  and  the  stone 
should  be  preferably  a  crushed  hard  sandstone  or  other  fire-resisting 
stone  in  graded  sizes  of  from  ^  to  2^  inches. 

516.  MIXING  AND  PLACING  CONCRETE  FOR  MASS 
CONSTRUCTION. — These  details  have  been  considered  in  Articles 
501  and  502.  In  addition  to  what  has  been  said  regarding  the 
placing  of  concrete,  reference  may  here  be  made  to  the  depositing 
of  concrete  for  mass  construction  under  water.  It  must  be  put 
in  place  without  separating  the  different  materials.  This  is  accom- 
plished by  lowering  it  in  large  buckets,  passing  it  through  tubes 
extending  to  the  work,  or  depositing  it  in  paper  bags  or  in  cloth 
sacks. 

In  the  construction  of  breakwaters,  sea-wall  foundations  for 


CONCRETE  CONSTRUCTION, 


6ir 


lighthouses,  piers,  dikes,  etc.,  the  concrete  is  often  molded  into 
heavy  blocks  and  then  placed  in  position  in  the  same  manner  as  that 
in  which  stone  masonry  is  laid,  by  means  of  a  stationary  or  float-' 
ing  derrick,  if  water  can  be  excluded  from  the  site.  If  the  water 
cannot  be  excluded  the  blocks  are  thrown  in  at  random. 

Blocks  of  concrete  weighing  40  tons  have  been  molded  for  this 
purpose  and  set  in  place. 

517.  MOLDS  AND  FORMS  FOR  PLACING  MASS  CON- 
CRETE CONSTRUCTION. — General  Considerations. — In  almost 
all  cases  it  is  necessary,  in  order  to  confine  concrete  in  place  or  in 
the  desired  form,  to  use  molds  or  forms  which  prevent  it  from 
running  while  wet  and  soft.  Wood  is  usually  employed  for  this 
purpose,  both  below  and  above  ground,  although  occasionally,  for 
small  heights,  the  earth  itself  is  all  that  holds  the  concrete  in 
place. 

Very  much  that  is  said  concerning  the  principles  of  mold  or 
form  construction  for  mass  concrete  may  be  said  also  of  these 
details  necessary  for  reinforced  concrete  construction. 

The  items  of  molds,  forms  and  centering  necessary  for  the  erec- 
tion of  plain  or  reinforced  concrete  construction  are  important  ones, 
and  the  expense  of  constructing  them  forms  a  large  part  of  the 
total  cost  of  the  work. 

Weak  forms,  also,  constitute  one  of  the  four  principal  causes  to 
which  have  been  attributed  the  failures  in  some  concrete  buildings. 
These  causes  are  (i)  imperfect  design,  (2)  poor  materials.  (3) 
faulty  construction  and  (4)  weak  forms. 

Materials  Used  for  Forms. — White  pine  is  the  best  wood  for 
forms,  and  should  be  used  for  ornamental  construction  and  fine 
face  work.  It  is  better  not  to  use  kiln-dried  wood,  as  it  absorbs 
much  moisture ;  and  better  not  to  use  very  green  lumber,  as  joints 
open  or  remain  open.  Medium  dry  lumber  is  therefore  the  best 
for  this  purpose.  For  panel  work  and  all  ordinary  work,  because 
of  the  expense  of  white  pine,  some  other  woods  may  be  substituted, 
such  as  the  soft  varieties  of  the  Southern  pines,  or  Norway  pine, 
spruce  or  fir.  Some  of  these  woods  are  more  suitable  than  white 
pine  for  struts  and  braces,  although  they  have  a  greater  tendency 
to  warp.    They  are,  as  a  rule,  stiffer  than  the  white  pines. 

Thickness  of  Wood  for  Forms. — Regarding  the  tliickness  of 
lumber  used  for  forms,  custom  differs  with  contractors  and  locali- 


-6i2  BUILDING  CONSTRUCTION.  (Ch.  X) 


ties.  Figured  in  commercial  thicknesses  measured  before  planing, 
in  some  cases  a  i-inch  thickness  is  used,  in  others  a  15/2-inch  thick- 
ness and  in  a  few  others  a  2-inch  thickness,  even  for  such  work 
as  panel  forms. 

*'For  ordinary  walls  13^-inch  stuff  is  good,  although  for  heavy 
construction  where  derricks  are  used  2-inch  stuff  is  preferable ;  while 
for  small  panels  i-inch  boards  are  lighter  and  easier  to  handle. 
For  floor  panels  i-inch  boards  are  most  common,  although  if  the 
building  is  eight  or  more  stories  in  height  i-inch  stuff  of  soft  wood 
is  likely  to  be  pretty  well  worn  out  before  the  top  of  the  building  is 
reached,  and  the  under  surface  of  the  concrete  will  show  the  wear 
badly.  For  sides  of  girders  either  i-inch  or  13^-inch  stuff  is 
sufficient,  while  2-inch  stuffy  is  preferable  for  the  bottoms  of  girders. 
Column  forms  are  generally  made  of  2-inch  plank."* 

Miscellaneous  Details  Regarding  Wood  Forms. — All  forms  should 
be  so  designed  that  they  may  be  put  up  and  moved  quickly,  used 
.over  again  as  many  times  as  possible  and  removed  with  as  little 
damage  as  possible  to  the  concrete  or  to  the  wood  itself. 

Forms  must  be  strong  enough  to  hold  any  loads  that  may  come 
upon  them  or  upon  the  concrete  and  strong  enough  to  have  a 
rigidity  sufficient  to  prevent  deflection  while  the  concrete  is  being 
put  in  place. 

For  exposed  faces  the  surfaces  next  to  the  concrete  is  dressed. 
The  forms  should  be  sufficiently  tight  to  prevent  loss  of  the  wet 
material.  Tongued-and-grooved  sheeting  surfaced  on  both  sides  is 
used,  but  is  not  required  for  heavy  work. 

All  dirt,  sawdust,  shavings,  etc.,  should  be'  cleaned  from  the 
forms  before  the  concrete  is  deposited,  and  forms  should  be  cleaned 
before  being  used  again. 

In  order  to  prevent  the  adhesion  of  the  concrete  to  the  wood 
forms,  crude  oil  or  "sludge"  is  generally  recommended.  Linseed 
oil,  soft-soap  and  various  other  greasy  substances  are  used  also  for 
this  purpose.  Oil  should  be  thin  enough  to  flow  and  fill  the  grain 
of  the  wood,  thus  acting  as  a  filler. 

Sharp  corners  should  be  avoided  as  much  as  possible,  as  the 
wood  is  apt  to  stick  to  them  ;  and  wherever  practicable  they  should 
be  slightly  splayed  to  facilitate  the  removal  of  the  forms. 


*  Sanford  E.  Thompson,  in  paper  on  "Forms  for  Concrete  Construction,"  read  before 
the  Third  Annual  Convention  of  the  National  Association  of  Cement  Users. 


CONCRETE  CONSTRUCTION. 


613 


No  forms  should  be  removed  from  reinforced  concrete  work 
before  the  architect  or  engineer  in  charge  has  been  notified.  For 
ordinary  and  mass  concrete  work,  as  well  as  for  reinforced  con- 
crete work,  the  best  contractors  have  definite  rules  for  the  minimum 
time  required  for  forms  to  be  left  in  place  in  ordinary  weather, 
and  these  periods  are  lengthened  for  changes  in  conditions  accord- 
ing to  the  judgment  of  the  superintendent  iji  charge. 

In  the  paper  above  referred  to,  Mr.  Sanford  E.  Thompson  makes 
the  following  statement  regarding  the  proper  time  to  move  the 
forms  in  concrete  work : 

''Conference  with  a  number  of  prominent  contractors  in  various 
parts  of  the  country  indicates  substantial  agreement  regarding  the 
minimum  time  for  leaving  in  forms.  As  a  guide  to  practice  the 
following  rules  are  suggested,  in  the  main  the  requirements  of  the 
Aberthaw  Construction  Company : 

''Walls  in  mass  work :  one  to  three  days,  or  until  the  concrete 
will  bear  the  pressure  of  the  thumb  without  indentation. 

"Thin  walls :   in  summer,  two  days ;  in  cold  weather,  five  days. 

"Slabs  up  to  6  feet  span:  in  summer,  six  days;  in  cold  weather^ 
two  weeks. 

"Beams  and  girders  and  long-span  slabs :  in  summer,  ten  days  or 
two  weeks ;  in  cold  weather,  from  three  weeks  to  one  month.  If 
shores  are  left  without  disturbing  them,  the  time  of  removal  of 
the  sheeting  in  summer  may  be  reduced  to  one  week. 

"Column  forms :  in  summer,  two  days ;  in  cold  weather,  four 
days,  provided  girders  are  shored  to  prevent  appreciable  weight 
weakening  columns. 

"Conduits :  two  or  three  days,  provided  there  is  not  a  heavy  fill 
upon  #them. 

"Arches :  of  small  size,  one  week ;  for  large  arches  with  heavy 
dead  load,  one  month." 

"A  very  important  exception  to  these  rules  applies  to  concrete  • 
which  has  been  frozen  after  placing,  or  has  been  m^aintained  at  a 
temperature  just  above  freezing.    In  such  cases  the  forms  must  be 
left  in  place  until  ^fter  warm  weather  comes,  and  then  until  the 
concrete  has  thoroughly  dried  out  and  hardened."* 

518.    EXAMPLES  OE  FORMS  FOR  MASS  CONCRETE 

*  "Reinforced  Concrete  in  Factory  Construction,"  published  by  the  Atlas  Portland 
Cement  Company,  iSlew  York. 


6i4  BUILDING  CONSTRUCTION.  (Ch.  X) 

CONSTRUCTION.— In  this  article  some  illustrations  of  typical 
wooden  forms  for  mass  concrete  construction  are  given,  and  they 
represent  also  the  types  used  for  similar  and  appropriate  parts  of 
reinforced  concrete  buildings. 

Concrete  walls  are  often  monolithic  structures,  molded  in  place, 
in  forms  made  of  planks  and  frames,  with  numerous  uprights  and 
struts,  cross-ties  and  bolts.  The  forms  may  be  constructed  as  they 
are  for  columns,  between  wooden  sides  extending  the  entire  height 
of  a  wall ;  or  they  may  be  built  in  panels  all  the  way  up  on  one  side, 
the  other  side  being  brought  up  as  the  concreting  proceeds ;  or  the 


Fig.  466.     Forms  for  Concrete  Wall.    Pacific  Coast  Borax  Refinery,  Bayonne,  N,  J. 


Uprights  may  be  fixed  in  place,  and  several  sections  of  sheeting  used 
at  a  time,  the  lower  ones  being  removed  from  the  hardened  concrete 
and  placed  on  top  of  the  one  last  set  and  the  concrete  then  carried 
on  up.  When  hollow  walls  are  constructed  core-boxes,  in  a'ddition 
to  the  usual  side  forms,  are  employed.  For  forms  erected  com- 
plete before  the  concreting  is  begun,  fairly  wet  mixtures  are  recom- 
•  mended ;  and  for  forms  v/ith  movable  panels,  dry  concretes  are  better. 
Different  kinds  of  ties,  some  patented,  are  used  to  hold  the  side  walls 
of  the  forms  together,  and  when  the  latter  are  removed  the  nuts  or 
castings  are  often  screwed  ofif,  leaving  the  bolts  or  ties  in  the  wall. 
Fig.  466*  shows  the  wood  form  used  in  the  walls  for  the  con- 

*  This  figure,  as  well  as  several  others  in  the  chapter,  are  reproduced  from  "Reinforced 
Concrete  in  Factory  Construction"  and  from  "Concrete  Construction  About  the  Home 
and  Farm,"  by  permission,  through  the  courtesy  of  the  Atlas  Portland  Cement  Company, 
of  r^ew  York. 


CONCRETE  CONSTRUCTION. 


615 


■struction  of  the  Pacific  Coast  Borax  building  at  Bayonne,  N.  J., 
erected  in  1897  and  1898,  and  one  of  the  very  first  reinforced  con- 
crete factory  buildings  in  the  United  States.  These  forms,  patented 
by  Mr.  Ernest  L.  Ransome,  the  designer  and  builder  of  the  factory, 
are  still  used  in  wall  construction.  The  special  feature  is  the  vertical 
standard  made  of  two  i  by  6-inch  boards  on  edge  with  a  slot  between, 
through  which  the  bolts  pass.  By  loosening  the  nuts  the  planks 
behind  the  standards  are  loosened  and  the  standards  raised.  In  this 
building  the  walls  were  built  in  sections  4  feet  high  with  central 
cores  to  form  the  hollow  walls.  White  pine  was  used  for  the  forms, 
and  it  is  state<i  that  the  salvage  on  the  lumber  probably  did  not 
amount  to  more  than  10  per  cent,  although  by  present  methods  the 
builders  usually  figure  about  30  per  cent. 


Fig.  467  illustrates  a  simple  expedient  used  to  prevent  wood  wall 
forms  from  bulging.  Through  two  holes  bored  in  both  sides  of  the 
form  a  wire  is  passed,  the  ends  of  which  are  tied  together.  A  piece 
of  wood  or  a  large  nail  is  then  used  to  twist  the  two  strands  of  the 
wire  together.  In  this  way  the  forms  can  be  drawn  together  and 
held  securely  in  place.  When  the  forms  are  ready  to  be  removed, 
the  wires  are  cut  at  the  sides  and  trimmed  ofif  even  with  the  wall  sur- 
faces, or  they  are  cut  ofif  about  an  inch  back  of  the  finished  surfaces 
and  the  ends  covered  with  cement  mortar  to  prevent  discoloration 
of  the  concrete  by  the  corrosion  of  the  metal. 

Fig.  468  shows  the  side  elevation  of  ordinary  wood  forms  for  a 
concrete  wall,  the  braces  being  made  of  2  by  4-inch  pieces  placed 


Fig.  467.    Device  for  Preventing  Wood  Forms  from  Bulging. 


A 

6t6  building  construction.  (Ch.-X) 


against  the  2  by  4-iiich  studs,  as  shown  in  Fig-  469.  The  construc- 
tion as  shown  in  the  figure  has  defects  which  should  be  noticed. 
The  braces  should  butt  against  the  studs  instead  of  being  nailed  to 
their  sides,  and  the  lower  ends  of  the  braces  should  rest  against 


Fig.    468.     Ordinary    Wood    Fig.  469.    Cross-section  of  Con-  Fig.  470.    Use  of  Clay 
Forms  for  Concrete  Wall.  crete  Wall  Footing,  Wood  Bank  for  Part  of 

Side  Elevation.  Forms,  Studs  and  Braces.  Forms. 


Top  Vieyv 


fvas/jers 


Fig.   471.     Movable  Wood  Forms  for  Concrete  Wall. 


3ecHon 


small  stakes  or  posts  or  on  sills  instead  of  simply  resting  on  the 
ground. 

Fig.  469  shows  the  cross-section  of  an  ordinary  low  concrete  wall 
in  course  of  construction,  with  the  wood  forms,  studs  and  bracing. 
The  concrete  wall  footing  also  is  shown. 

Fig.  470  shows  a  cross-section  of  a  low  concrete  wall  and  footing 


CONCRETE 


CONSTRUCTION. 


617 


built  against  a  bank  of  hard  clayey  soil.  In  this  case  the  bank  is 
made  to  do  duty  for  half  the  form. 

The  faults  pointed  out  for  Fig.  468  are  seen  in  Figs.  469  and  470 
also. 

Fig.  .471  shows  the  elevation,  section  and  top  view  of  one  kind  of 
movable  form  used  in  building  solid  concrete  walls  of  any  height. 
The  form  is  put  in  place  and  filled  with  concrete ;  and  after  the 
latter  has  set,  the  bolts  are  withdrawn  and  the  form  raised  high 
enough  to  allow  its  lower  part  to  overlap  and  the  lowest  set  of  bolts 
to  rest  on  the  completed  concrete  wall.  This  assists  in  keeping  the 
wall  plumb.    The  bolts  are  well  greased  each  time  to  facilitate  their 


Movable  Wood  Forms  for  Concrete  Wall. 


removal  after  the  concrete  has  set ;  and  the  holes  left  are  filled  with 
mortar  made  with  the  same  proportions  of  cement  and  sand  used  in 
the  concrete. 

Fig.  472  shows  another  view  of  a  similar  form,  with  detail  of 
collar  and  set-screw  sometimes  used  instead  of  the  ordinary  threaded 
bolt  with  nut  and  washer,  where  walls  or  columns  are  of  various 
dimensions. 

Fi?-  473*  shows  another  style  of  wood  forms  used  for  heavy 


*  This  Fig.  473  and  Figs.  474  and  475  also  are  reproduced  from  "Concrete, 
Plain  and  Reinforced,"  by  Taylor  &  Thompson,  by  permission,  through  the  courtesy 
of  the  authors.  In  this  work  much  valuable  information  and  many  illustrations  relating 
to  forms  will  be  found. 


6i8 


BUILDING 


CONSTRUCTION. 


(Ch.  X) 


concrete  wall  construction,  in  which  the  ties  consist  of  wire  twisted 
to  hold  the  side  forms  in  place.  This  is  the  method  illustrated  also 
in  Fig.  467.    This  is  an  inexpensive  method  of  connection. 

Fig.  474  shows  a  simple  form  for  a  concrete  foundation  wall.  The 
following  description  is  given  by  the  authors  of  the  work  referred 
to  in  the  footnote  for  Fig.  473 :  ''A  ranger,  AA,  is  lined,  and 
lightly  spiked  to  occasional  studs  whose  pointed  ends  are  driven  into 
.the  ground,  and  kept  in  line  by  strips  of  wood  running  from  it  to 


Fig.  473.     Wood  Forms  for  Heavy  Concrete  Wall. 

Stakes  in  the  bank.  In  some  cases  it  may  be  advisable  also  to  set 
a  lower  ranger  between  the  studs  and  the  bank.  Occasional  stakes, 
BB,  are  driven  into  the  ground,  and  a  ranger,  CC,  for  the  inside  row 
of  studs,  is  laid  on  top  of  them,  lined,  and  lightly  spiked  to  them, 
while  the  upper  ends  of  these  studs  are  held  by  cleats,  DD,  run 
across  to  the  inner  row  of  studs.  Vertical  strips,  EE,  about  of 
an  inch  square,  are  placed  inside  of  each  stud  for  the  form  planks 
to  rest  against,  and  after  a  section  of  concrete  is  laid  are  easily 


Fig.  475.  Wood  Forms  for  Hollow  Outside  Concrete  Wall. 


620 


BUILDING  CONSTRUCTION.  (Ch.  X) 


knocked  out  and  the  form  planks  raised  to  another  level.  The  first 
layer  of  concrete  is  allowed  to  flow  out  under  the  lower  plank  to 
form  a  footing,  above  which  the  cellar  floor  is  laid.  The  number  of 
laborers  and  the  height  of  the  forms  should  be  such  that  the  planks 


Fig.  476.     Single  Wood  Form  Shutter  for  Concrete  Column  in  Brick  Outside  Wall. 


may  be  raised  each  morning,  provided  the  concrete  is  hard  enough 
to  withstand  the  pressure  of  the  thumb  without  being  indented." 

Fig.  475  shows  a  design  for  wood  forms  for  a  hollow  concrete 
wall.  The  arrangement  of  the  ribs  and  bolts  is  such  that  the  bolts, 
do  not  have  to  pass  through  the  concrete.  When  the  concrete 
reaches  the  level  of  the  bolt  the  forms  are  raised. 


Fig.  477.    Double  Wood  Form  Shutters  for  Concrete  Column  in  Brick  Party-wall. 


The  sectional  drawing  at  the  right  in  the  figure  illustrates  a 
tongued-and-grooved  molding  with  edges  slightly  bevelled.  This 
serves  to  form  the  horizontal  joints,  and  takes  the  place  of  the 
triangular  strips  often  nailed  on  the  planks  when  the  surfaces  are  not 
finished  to  show  the  monolithic  construction. 


CONCRETE  CONSTRUCTION, 


621 


Figs.  476,  477  and  478*  show  methods  employed  to  save  form 
materials  in  a  building  in  which  the  walls  were  of  brick  and  the 
columns,  girders  and  beams  of  concrete.  The  brickwork  was  erected 
first  and  proper  recesses  and  flue-like  openings  were  left  for  the 
concrete  columns,  girders,  etc.  In  this  way  the  sides  of  the  recesses 
served  the  purpose  of  two  or  three  sides  of  the  wood  forms,  and  into 
these  recesses  the  wet  concrete  was  poured,  reinforced  or  not,  as 
required. 

Fig.  476  is  a  horizontal  section  of  an  outside  wall  column  recess 

showing  side  slats  in  the  brickwork 
for  anchoring  or  binding  the  con- 
crete column  and  wooden  form 
"shutter"  with  upright  and  wire  ties. 

Fig.  477  is  a  horizontal  section  of 
a  party-wall  column  recess  showing 
side  slots,  uprights,  furring  pieces, 
wooden  form  "shutters,"  wire  ties, 
etc. 

Fig.  478  shows  a  vertical  section 
of  a  recess  left  for  outside  wall  con- 


1! 

Fig.  478.   Wood  Side  Form  for  Con-  Crete  girder,  with  wooden  side  form 

Crete  Girder  in   Brick  Wall.  i     ^i.  i.     r  j. 

shutters,    supports  for  same,  etc. 

For  columns  it  is  necessary  to  make  a  form  for  each  side,  and  to 
place  frames  around  these  side  forms  at  intervals  determined  by  the 
pressure  to  be  resisted.  The  frames  are  secured  in  various  ways,  by 
bolts  running  through  the  ends  of  the  pieces,  by  blocks  and  wedges,, 
by  hooks  and  staples,  etc.  Two  by  4-inch  pieces  are  generally  used 
for  the  frames,  and  the  side  forms  vary  in  thickness  from  %  of  an 
inch  to  varying  greater  thicknesses. 

Fig.  479  shows  the  forms  used  for  the  concrete  columns  of  the 
machine  shops  for  the  Bullock  Electric  Company,  at  Norwood,  Ohio. 
The  column  band  or  clamps  were  of  2  by  4-inch  stuff,  and  all  the 
forms  were  of  yellow  pine,  costing  $20  per  thousand  feet.  For  the 
beam  and  column  panel  forms  i  by  6-inch  tongued-and-grooved 
stock  was  employed,  and  this  was  planed  on  one  side  and  on  the 
edges.  The  column  bands  or  clamps  were  held  together  by  blocks 
and  wedges,  as  shown  on  the  drawing.    On  one  side  the  piece  was 


*  Figs.  476,  477  and  478  are  reproduced  through  the  courtesy  of  the  Cement  Age, 
June,  1906.  They  appeared  also  in  a  paper  on  "Cost  Reduction  of  Reinforced  Concrete 
Work,"  by  Mr.  E.  P.  Goodrich,  read  before  the  Association  of  American  Portland  Cement 
Manufacturers,  at  Atlantic  City,  N.  J.,  in  June,  1906. 


622 


BUILDING  CONSTRUCTION.  (Ch.  X) 


loose,  so  that  the  same  clamp  could  be  used  for  a  narrower  column 
by  changing  the  position  of  the  blocks.  The  clamps  were  spaced 
i8  inches  apart  near  the  bottom,  the  intervals  increasing  to  24 
inches  near  the  top. 

519.  CONCRETE  FOUNDATIONS  AND  CELLAR  WALLS 
FOR  LIGHT  BUILDINGS.— G^n^ra/  Considerations.— For  the 
foundation  and  cellar  walls  of  frame  buildings  concrete  can  be  used 
to  great  advantage  by  the  carpenter,  because  all  of  the  lumber 
required  for  the  forms  can  afterward  be  used  in  the  construction  of 
the  superstructure,  which  means  a  considerable  saving  in  the  cost 


y5ecf/on  of  Co/umn  Mou/d 
-2'x4: 


d/ock 


Top  of 

F/oor-} 


1- 


^^pac/ng  of  Co/umn  0an£f5 


^ftfrf  t/ev^af/on  of  Co/u/77/7  Mou/d 
Fig.  479,    Wood  Forms 


for  Concrete  Columns. 


of  the  walls.  By  using  concrete  the  carpenter  can  start  his  work 
from  the  ground  and  have  full  control  over  it.  He  can  also  build 
the  chimneys  of  the  same  material,  and  in  this  way  no  other 
mechanics  are  required  about  the  building  until  it  is  ready  for  paint- 
ing and  plastering. 

Requisite  Dimensions  for  Concrete  Walls  and  Footings  for  Lighi 
Buildings. — The  requisite  thickness  of  concrete  walls  naturally 
depends  in  a  great  measure  upon  the  quality  of  the  concrete,  whether 
or  not  it  is  reinforced,  and  the  purpose  for  which  the  walls  are  to 
Idc  used.  Messrs.  Taylor  &  Thompson  state  that  ''a  single  con- 
crete wall,  4  inches  thick,  with  its  base  spread  to  provide  a  footing, 


CONCRETE  CONSTRUCTION.  623 

is  at  least  equivalent  to  an  8-inch  brick  wall ;  and  a  6-inch  concrete 
wall  is  at  least  equivalent  to  12  inches  of  brick."* 

They  recommend,  however,  that  all  walls  6  inches  thick  and  under 
be  reinforced  with  small  rods,  about  ^  of  an  inch  in  diameter, 

placed  from  18  inches  to  2  feet  apart, 
not  only  to  increase  their  permanent 
strength,  but  to  guard  against  acci- 
dents during  or  immediately  after 
construction. 

The  writer's  experience  with 
cement  walls  leads  him  to  believe 
that  the  foregoing  statement  regard- 
ing the  comparative  thickness  of 
concrete  and  brick  walls  has  not  been 
overestimated  as  far  as  the  strength 
and  stiffness  are  concerned ;  but  it 
is  often  necessary  to  make  walls 
thicker  than  is  absolutely  required 
for  strength.  A  4-inch  wall  of  or- 
dinary concrete  is  likely  to  be  pene- 
trated by  moisture  in  a  severe  rain- 
storm, and  it  has  little  stability  to 
withstand  a  thrust  unless  reinforced 
by  piers  or  buttresses. 

For  cellar  and  foundation  walls,, 
therefore,  the  writer  would  not 
recommend  a  thickness  less  than  8 
inches,  except  for  very  small  build- 
ings. Interior  partitions  supporting 
floors  may  be  6  inches  thick,  and  partitions  which  support  no  weight 
may  be  made  as  thin  as  3  inches. 

Foundation  Walls  for  Small  Buildings. — In  Fig.  480  is  shown  a 
section  through  the  cellar  wall  of  a  two-story  frame  building  which 
is  well  adapted  to  clay  soils  in  northern  latitudes.  In  all  soils  which 
"heave"  under  the  action  of  frost  it  is  very  desirable  to  batter  the 
outer  face  of  the  wall,  so  that  as  the  ground  works  up  it  comes  away 
from  the  wall. 

In  dry  soils  and  soils  not  affected  by  frost  the  walls  may  as  well 
be  plumb  on  the  outside  and  of  a  uniform  thickness  of  8  inches. 

*  "Concrete,  Plain  and  Reinforced."     Taylor  &  Thompson.  • 


Fig.  480.  Typical  Concrete  Cellar  Wall 
and  Footing  for  Frame  Building. 


624 


BUILDING  COXSTRUCTION. 


(Ch.  X) 


For  frame  cottages,  stables  and  small  barns  a  wall  such  as  shown 
in  F'rg.  481  will  answer,  and  in  localities  where  frost  does  not  have 
to  be  taken  into  consideration,  and  where  the  ground  is  sufficiently 
firm  to  stand  vertically,  the  cellar  walls  of  small  frame  buildings  can 
be  built  as  shown  in  Fig.  482,  the  concrete  being  placed  directly 
against  the  bank.  In  a  wet  climate  the  writer  w^ould  not  ^^dvise 
building  a  wall  in  this  way. 

It  should  always  be  kept  in  mind  that  the  thinner  the  wall  the 
stronger  and  denser  should  be  the  concrete. 

It  should  be  noticed  that  all  walls  shown  have  bolts  imbedded  for 
securing  the  plates  or  sills.   These  bolts  cost  very  little  and  are  easily 


Fig.   481.     Battered  Concrete  Cellar  Wall.      Fig.    482.      Concrete    Cellar    Wall.  Light 
Light  Luilding.  -Cuikling.     Firm   Earth.     No  Frost. 

built  in,  while  they  hold  the  plates  or  sills  tightly  to  the  wall  and 
also  strengthen  it  to  resist  the  thrust  of  the  dirt  filling  when  there  is 
no  great  weight  on  it. 

Quantities  and  Cost  of  Concrete  M'^alls. — Concrete  work,  except 
an  walks  and  floors,  is  almost  always  measured  by  the  cubic  yard,  of 
27  cubic  feet.  Sand  and  gravel  are  commonly  contracted  for  by  the 
cubic  yard,  while  crushed  stone  is  sold  by  the  ton  and  by  the  yard. 

Knowing  the  cost  per  barrel  of  cement,  and  per  yard  of  sand, 
gravel  or  broken  stone,  the  cost  of  the  ingredients  per  cubic  yard  of 
rammed  concrete  may  be  determined  very  closely  by  means  of  the 
following  table : 


a 


CONCRETE  CONSTRUCTION. 


TABLE  XXXVII. 

Quantities  Required  to  Make  a  Cubic  Yard  of  Rammed 

Concrete.* 

Proportions.  Quantities  required  per  yard  of  concrete. 


Cement.  Sand.    Gravel  or  stone.  Cement,  Sand.      Gravel  or  stone. 

Sack.  cu.  ft.  cu.  ft.           bbls.  yds.  yds. 

I  3  1-9  0.42  0.85 

I  2  4               1.45  0.45  a86 

I               2  5.1-3  0.38  0.95 

I  2^  5               1.2  0.45  0.90 

I  3  6               1.0  0.40  0.92 


Thus,  if  in  any  given  locality  cement  costs  $2  per  barrel,  sand  50 
cents  a  yard,  and  coarse  gravel  60  cents  a  yard,  the  cost  per  cubic 
yard  of  a  1:2  14  mixture  will  be : 

For  cement   1-45  X  $2.00  =:  2.90 

For  sand   0.45  X     .50=  .22^ 

For  gravel   ■  0.86  X    .60=  .51^ 

Total  cost  for  materials,  $3.64  per  yard. 

The  cost  of  mixing  concrete  by  hand  and  placing  in  forms  for 
cellar  walls  from  8  to  12  inches  thick  should  not  exceed  $1.50  per 
yard,  with  the  wages  at  175^  cents  per  hour;  and  with  experience 
this  may  be  reduced  to  $1.25  per  yard.  As  a  rule  the  thicker  the  body 
of  concrete  the  cheaper  it  can  be  placed. 

Forms  for  Concrete  Cellar  Walls  for  Light  Buildings. — For  the 
cellar  walls  of  wooden  buildings  it  will  be  more  economical  to  build 
the  forms  of  ^material  that  may  be  afterward  used  in  constructing 
the  building,  and  this  can  be  done  so  that  there  will  be  little  waste  of 
lumber. 

Fig.  483  shows  a  good  and  economical  method  for  building  the 
false  work  for  the  wall  shown  in  Fig.  480,  the  lumber  required  being 
of  those  dimensions  most  extensively  used  in  the  construction  of 
frame  buildings. 

For  a  wall  of  the  section  shown  in  Fig.  480  the  footing  should 
be  put  in  before  the  wall  forms  are  set  up.  Except  in  sand  and 
gravel,  no  side  pieces  are  required  for  footings,  as  all  other  soils  will 

*  These  figures  may  be  considered  as  a  fair  average  where  the  aggregate  contains 
stone  up  to  2  inches  in  diameter.  For  'finer  aggregates  slightly  greater  quantities  of  all 
materials  are  required. 

Where  gravel  is  used  just  as  it  comes  from  the  bank,  without  the  addition  of  sand, 
add  together  the  items  for  sand  and  gravel. 


626 


BUILDING  CONSTRUCTION.  (Ch.  X) 


stand  vertically  for  a  depth  of  8  to  lo  inches ;  hence  all  that  is  neces« 
sary  is  to  dig  the  trench  the  exact  width  and  depth  required  for  the 
footings.  The  concrete  is  then  placed  in  the  trenches  and  tamped 
with  a  rammer,  such  as  is  shown  in  Fig-  486.  The  concrete  for 
footings  should  be  mixed  just  wet  enough  to  have  the  water  flush 
to  the  surface  when  tamped.  This  is  not  on  account  of  considera- 
tions of  strength,  but  because  moderately  dry  concrete  sets  up 
quicker  than  wet  concrete  and  is  rather  more  convenient  to  handle. 


Fig.  483.     Forms  for  Concrete  Wall   Shown  in   Fig.  480. 


Before  placing  the  concrete  for  footings  it  is  a  good  idea  to  drive 
stakes  in  the  trenches  about  6  feet  apart,  with  their  tops  levelled  to 
give  the  exact  height  for  the  top  of  the  footings. 

The  concrete  can  then  be  readily  levelled  with  the  tops  of  these 
stakes,  which  may  be  left  in  place  without  harm. 

To  start  erecting  the  wall  form,  stringers  TT  should  first  be 


CONCRETE  CONSTRUCTION. 


627 


carefully  placed  on  the  cellar  bottom  and  secured  by  stakes  in  a 
position  that  will  give  the  correct  line  for  the  inside  of  the  wall 
when  the  uprights  and  sheeting  are  placed  inside  of  them.  Two 
uprights  12  or  16  feet  apart  are  then 'set  up,  and  another  stringer 
secured  to  them  at  about  the  level  of  the  top  of  the  wall.  These 
uprights  should  be  carefully  plumbed  and  well  braced  by  diagonal 
braces  nailed  to  short  stakes  driven  in  the  cellar  bottom.  The  two 
stringers  then  form  a  guide  for  the  intermediate  uprights,  which  can 
be  quickly  set  up  and  lightly  secured  by  nails.  One  sheeting  board 
is  then  nailed  to  the  bottom. 

After  the  inner  form  is  set  up'  the  outer  one  is  easily  erected  and 
secured  to  the  inner  one  as  indicated. 

On  account  of  the  proximity  of  the  bank  it  will  usually  be 
found  more  economical  to  secure  the  bottom  of  the  outer  uprights 
by  twisted  wires,  as  shown  in  Fig.  483,  an  8-inch  board  being  first 
nailed  along  the  bottom,  and  loose  spacing  blocks  D  laid  in.  The 
wires  are  than  twisted  until  the  outer  form  is  brought  tight  against 
the  spacing  blocks.  After  the  wall  has  set  the  wires  can  be  cut  with 
a  chisel  and  the  form  pulled  up.  The  spacing  blocks,  D,  should  be 
removed  as  the  concrete  is  put  in- 

The  outer  form  should  be  sheeted  to  the  top  of  the  bank  before 
placing  any  concrete,  but  it  is  more  convenient  to  place  the  sheeting 
on  the  inner  form  just  ahead  of  the  concrete  to  facilitate  tamping. 

If  the  building  happens  to  be  built  on  a  sand  or  gravel  bank  it  will 
also  be  cheaper  to  mix  the  concrete  in  the  cellar,  otherwise  the  con- 
:rete  can  be  more  cheaply  mixed  on  the  bank  and  wheeled  to  the 
forms. 

The  outer  face  of  the  wall  above  the  bank  is  plumbed  by  nailing 
tapered  pieces  to  the  uprights,  as  shown  at  S. 

If  this  portion  of  the  wall  is  to  be  blocked,  then  a  separate  form 
can  be  used  with  greater  economy  than  by  using  the  same  form 
and  adapting  it  as  just  described. 

At  AA  is  shown  the  method  of  suspending  the  bolts  which  are 
to  be  imbedded  in  the  concrete  for  securing  the  sill  to  the  wall. 

The  top  of  the  sheeting  should  be  levelled  at  the  exact  height 
of  the  wall  to  form  a  guide  for  levelling  the  concrete. 

It  will  be  noticed  that  the  method  adopted  for  staying  the  uprights 
(Fig.  483)  enables  scantling  of  any  length  greater  than  the  height 


628 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


of  the  wall  to  be  used,  as  8  or  9-foot  lengths,  so  that  they  can 
afterward  be  used  for  studding. 

Fig.  484  shows  the  simplest  method  of  building  the  forms  for 
the  wall  shown  by  Fig.  481,  the  principal  variations  from  the  details 
shown  in  Fig.  483  being  the  manner  in  which  the  uprights  are 
secured  at  the  bottom.  For  the  method  shown  in  Fig.  484  the 
forms  must  be  erected  before  the  footings  are  put  in,  the  sheeting 
being  started  6  or  8  inches  above  the  bottom  of  the  trench  and  the 
concrete  spread  out  under  it.    While  this  method  is  satisfactory 


Fig.   484.     Forms  for   Concrete   Wall   Shown  Fig.  485.    Forms  for  Concrete  Wall 

in  Fig.  481.  Shown  in   Fig.  482. 


for  a  light  wall,  it  is  not  as  good  as  that  shown  by  Fig.  483  for 
a  heavy  wall. 

The  bottoms  of  the  uprights  in  Fig.  484  should  be  tapered  from 
the  bottom  of  the  sheeting  and  planed,  otherwise  it  will  be  difficult 
to  withdraw  them  without  breaking  the  concrete.  It  is  also 
advisable  to  give  the  tapered  ends  a  coat  of  crude  oil. 

Fig.  485  shows  a  method  of  erecting  the  forms  when  the  con- 
crete is  placed  directly  against  the  earth.  In  this  case  the  concrete 
should  be  put  in  to  within  about  6  or  10  inches  of  the  top  of  the 


CONCRETE  CONSTRUCTION. 


629 


bank  before  the  outer  form  is  set  up.  The  outer  form  is  secured 
at  the  bottom  to  the  inner  form  by  ^-inch  bohs,  about  3  feet  apart, 
with  spacing  blocks  between  the  forms  to  hold  them  the  right 
distance  apart.  As  the  concrete  is  placed  these  spacing  blocks  should 
be  taken  out. 

In  starting  the  concrete  between  the  forms  the  top  of  the  concrete 
already  in  place  should  be  well  wet  and  covered  with  about  ^  inch 
of  thin  mortar,  mixed  i  to  i,  cement  and  sand,  to  cause  adhesion. 

The  erection  of  the  forms  for  concrete  work  naturally  admits  of 
considerable  variation  in  the  details  of  construction  and  affords 
ample  opportunity  for  the  use  of  ingenuity  and  good  judgment 
on  the  part  of  the  contractor. 

Thickness  of  Sheeting  and  Size  and  Spacing  of  Uprights  for 
Forms  for  Light  Buildings. — These  dimensions  should  be  governed 
somewhat  by  the  character  of  the  concrete  work.  The  forms  should 
be  stiff  enough  so  that  they  will  not  spring  under  *he  weight  of 
the  concrete  or  when  the  concrete  is  tamped.  As  a  rule  the  pressure 
of  wet  concrete  is  considerably  greater  than  that  of  dry  concrete, 
although  if  the  latter  is  properly  tamped  the  effect  on  the  forms 
is  about  the  same.  For  a  rough  wall,  built  of  wet  concrete,  a  slight 
springing  of  the  sheeting  does  no  particular  harm ;  but  where  a 
nice  appearance  is  desired  there  should  be  no  springing. 

For  the  class  of  work  shown  in  the  accompanying  illustrations  the 
uprights  should  be  spaced  about  2  feet  on  centers  where  %-inch 
boards  are  used  for  sheeting ;  but  if  plank  sheeting  is  used,  the 
uprights  may  be  spaced  5  feet  on  centers. 

With  %-inch  sheeting  2  by  4's  may  be  used  for  the  uprights,  but 
they  should  be  braced  about  every  5  feet  in  height.  In  forms  such 
as  are  shown  in  Figs.  483,  484  and  485,  if  the  2  by  4's  show  a  ten- 
dency to  spring  they  may  be  tied  together  through  the  wall  by  soft 
iron  wire — baling  wire  will  answer — twisted  at  the  bottom  of  the 
form  as  shown  in  Fig.  483.  This  generally  is  cheaper  than  addi- 
tional braces  and  is  not  in  the  way.  If  the  forms  do  spring  under 
the  weight  of  the  concrete  they  should  be  immediately  braced  to 
prevent  further  springing,  but  no  attempt  should  be  made  to 
straighten  them,  as  concrete  should  not  be  disturbed  after  it  has 
commenced  to  set.  * 

The  sheeting  should  be  nearly,  although  not  absolutely,  water- 
tight, and  should  be  free  from  knot  holes,  and  the  boards  should 


630  BUILDING  CONSTRUCTION.  (Ch.  X) 


be  in  8-inch  or  lo-inch  widths  and  surfaced  on  the  inner  side. 

Kind  of  Lumber  Required. — For  such  forms  as  are  described  in 
this  article  either  spruce,  fir,  hemlock  or  pine  boards  and  scantlings 
may  be  used ;  and  moderately  green  lumber  will  be  found  better 
than  very  dry  lumber,  as  it  is  not  as  badly  affected  by  the  moisture 
in  the  concrete. 

When  Forms  for  Light  Building  Foundations  May  Be  Removed. 
— Where  there  is  no  pressure  against  the  wall  the  forms  can  gen- 
erally be  removed  in  from  24  to  48  hours  after  the  wall  is  com- 
pleted, or  just  as  soon  as  the  top  concrete  is  so  hard  that  it  cannot 
be  indented  by  the  thumb.  The  sooner  the  forms  are  removed  the 
less  is  the  lumber  affected. 

After  the  forms  are  taken  down  the  inside  of  the  wall  should  be 
braced  until  the  first  floor  is  in  place,  to  protect  the  wall  from  any- 
thing falling  against  it.  If  this  is  done  the  sill  may  be  bolted  on 
24  hours  aft1*r  the  w^all  is  completed,  and  the  floor  joists  set  the 
next  day ;  but  no  great  weight  should  be  placed  on  the  wall  until 
it  is  seven  days  old. 

Cost  of  Form  Work  for  Foundations  for  Light  Buildings. — For 
the  forms  shown  in  this  article  the  writer  estimates  that  the  cost 
of  putting  up  and  taking  down,  not  including  the  lumber,  is  about 
6  cents  per  square  foot  of  wall,  which  for  an  average  thickness 
of  wall  of  8  inches  is  equivalent  to  $2.40  per  yard  of  concrete. 

With  a  I  to  73^  mixture,  cement  at  $2  a  barrel,  gravel  at  60 
cents  a  yard,  delivered  at  the  site,  common  labor  at  lyy^  cents  an 
hour,  and  carpenters'  wages  at  30  cents  an  hour,  the  total  cost  of 
the  cellar  walls,  averaging  8  inches  thick,  should  approximate  $7 
per  yard,  or  171^  cents  per  superficial  foot.  This  does  not  include 
the  cost  of  the  lumber,  as  it  is  assumed  that  this  will  be  used  in 
the  superstructure.  At  $10  per  thousand  bricks  in  the  wall,  wall 
measure,  an  8-inch  common  brick  wall  will  cost  15  cents  per  square 
foot,  and  a  12-inch  wall  22}^  cents. 

Rammers  and  Puddlers. — All  concrete  should  be  either  tamped  or 
puddled  whenever  practicable.  For  dry  and  medium  mixtures  thor- 
ough tamping  is  necessary  iw  order  to  obtain  a  solid  mass,  and  even . 
with  very  wet  mixtures  pockets  or  voids  may  occur  unless  the  mass 
is  puddled.  A  mixture  which  does  not  quake  in  the  wheelbarrow 
should  be  deposited  in  layers  not  over  6  inches  thick,  and  thor- 
oughly tamped  or  rammed  with  an  iron  rammer,  such  as  is  shown 


CONCRETE  CONSTRUCTION. 


631 


in  Fig.  486,  in  the  first  drawing.  Against  the  forms  a  rammer 
such  as  is  shown  in  the  second  drawing  is  more  satisfactory. 

A  quaking  mixture  may  be  deposited  in  layers  10  to  12  inches 
thick,  and  should  be  puddled  with  a  square-pointed  spade  or  a 
raminer  like  that  shown  in  the  second  drawing.  A  rammer  such 
as  is  shown  in  the  third  drawing,  made  from  a  piece  of  2  by  3-inch 
scantling,  is  very  effective  for  many  kinds  of  work,  the  rammer 
being  shoved  through  the  entire  thickness  of  the  mass. 

For  exposed  walls  built  in  forms  the  concrete  next  to  the  forms 
should  be  puddled  by  thrusting  down  next  to  the  mold  a  square- 
pointed  spade  or  a  thin  tool  like  a  sidewalk  scraper,  as  the  concrete 


Fig.  486. 


Types  of  Rammers  and  Puddlers  for  Concrete. 


is  placed,  working  it  up  and  down,  and  at  the  same  time  pushing 
back  the  large  stones  or  pebbles  so  that  the  thinner  mortar  may  run 
in  and  form  a  smooth  and  fairly  uniform  surface.  Care  must  be 
taken,  however,  not  to  pry  on  the  concrete  so  as  to  spring  the  molds. 
The  fourth  and  fifth  drawings  of  Fig.  486  show  the  tools  used  for 
puddling  the  concrete  in  the  factory  buildings  of  the  United  Shoe 
Machinery  Company  at  Beverly,  Mass. 

The  concrete  was  mixed  quite  wet  and  deposited  in  layers  about 
12  inches  thick;  and  the  tools  were  made  so  that  they  could 
penetrate  16  inches  without  covering  their  heads. 

521.  MASS  CONCRETE  AND  REINFORCED  CONCRETE 
CONSTRUCTION. — Many  examples  of  mass  concrete  construe- 


632 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


tion  could  be  given  and  illustrated,  but  a  sufficient  number  have 
been  cited  to  explain  the  principles  of  this  portion  of  the  subject. 

In  the  following  third  subdivision  of  this  chapter,  relating  to 
"Reinforced  Concrete  Construction,"  other  examples  of  buildings 
and  parts  of  buildings  are  given,  many  of  the  details  of  which,  a*side 
from  the  reinforcement,  serve  also  for  mass  concrete  construction. 

3.    REINFORCED  CONCRETE  CONSTRUCTION. 

522.  DEFINITION  OF  REINFORCED  CONCRETE.— As 
distinguished  from  *'mass  concrete"  or  "massive  concrete,"  con- 
taining no  metal  reinforcement,  reinforced  concrete  has  already  been 
defined  in  Article  513.  Perhaps  as  good  a  definition  as  any  is  that 
given  in  the  regulations  of  the  New  York  Bureau  of  Buildings,  and 
also  in  the  building  laws  of  Chicago,  St.  Louis,  San  Francisco, 
Buffalo  and  some  other  cities,  which  describe  it  as  "an  approved 
concrete  mixture  reinforced  by  steel  of  any  shape,  so  combined  that 
the  steel  will  take  up  the  tensional  stresses  and  assist  in  the  resistance 
to  shear." 

The  terms  "concrete-steel,"  "steel-concrete,"  "ferro-concrete," 
"armored  concrete,"  etc.,  have  also  been  used  for  this  heterogene- 
ous material,  but  are  not  now  in  general  use. 

523.  SUBDIVISIONS  OF  REINFORCED  CONCRETE 
CONSTRUCTION. — In  considering  or  specifying  this  kind  of 
work  it  is  sometimes  divided  into  two  classes:*  (i)  "Monolithic 
Construction,"  or  concrete  molded  in  place,  and  (2)  "Unit  Con- 
struction," or  concrete  which  is  not  molded  in  place,  but  which  is 
manufactured  at  the  factories,  put  together  there  in  units,  such  as 
columns,  girders,  beams,  slabs,  etc.,  and  then  brought  to  the 
building  and  put  in  place. 

*      I.    DEFINITIONS,  HISTORY,  USES  AND  EXAMPLES. 

524.  HISTORICAL  NOTES  ON  REINFORCED  CON- 
CRETE CONSTRUCTION.— In  1850  M.  Lambot  built  a  small 
boat  of  reinforced  concrete,  and  in  1855  exhibited  it  at  the  Paris 
Exposition  and  took  out  patents. 

In  1861  Joseph  Monier,  a  gardener  of  Paris,  constructed  flower- 
pots, tubs,  tanks  and  basins  for  use  in  horticulture,  and  Frangois. 


*  See  "General  Specifications  for  Concrete  Work  as  Applied  to  Building  Construc- 
tion," by  Wilbur  J.  Watson,  Cleveland,  Ohio. 


REINFORCED  CONSTRUCTION. 


633 


Coignet  explained  his  theories  of  reinforced  concrete  for  beams, 
arches,  large  pipes,  etc. 

In  1867  both  Monier  and  Coignet  exhibited  some  work  at  the 
Paris  Exposition,  and  Monier  took  out  some  patents  on  the  new 
material.  His  system  of  construction,  although  somewhat  changed 
and  modified,  is  still  used  in  slab  reinforcement  and  other  details. 
It  consists  essentially  of  two  sets  of  parallel  rods  placed  over  and 
at  right-angles  to  each  other,  forming  a  mesh  or  trellis.  There 
was  at  that  time,  however,  no  general  application  of  the  principle 
or  system  to  building  construction  and  it  was  confined  to  very 
narrow  fields. 

In  1885  the  German  and  Austrian  engineers  took  the  matter  up, 
and  G.  A.  Wyss  and  J.  Bauschinger  began  a  series  of  experiments 
and  tests  in  constructions  of  the  Monier  system  and  in  1887  pub- 
lished the  results  together  with  formulas  for  use  in  design. 

From  1887  on,  Austria  especially  advanced  the  theory  and  prac- 
tical design,  and  shortly  after  this,  among  those  engineers  who  did 
the.  most  to  develop  the  new  construction,  was  Melan,  who  used 
I-beams  and  T-beams  to  resist  the  compressive  as  well  as  the  tensile 
stresses.  Hundreds  of  arch  bridges  have  been  constructed  after 
this  system. 

In  Germany,  although  for  some  time  government  restrictions 
delayed  the  development  of  reinforced  concrete  in  building  con- 
struction, it  is  now  extensively  employed,  over  two  hundred  differ- 
ent types  or  systems  being  in  use  there  in  1908. 

In  France  neither  Monier  nor  any  of  his  countrymen  appeared  to 
appreciate  the  scientific  value  of  his  ideas ;  but  many  other  types  of 
tension  and  shear-resisting  reinforcements  were  patented  from  time 
to  time,  and  among  those  elements  now  widely  used  are  those  of  the 
system  introduced  by  Hennebique,  who  was  probably  the  first  to 
make  use  of  "bent-up"  bars  and  stirrups. 

In  England,  as  in  the  United  States,  the  first  applications  of  iron 
and  steel  to  concrete  reinforcements  were  due  to  efforts  made  to 
make  floor  construction  fire-proof.  Mr.  Thaddeus  P.  Hyatt,  a 
native  of  New  Jersey,  residing  in  England,  conceived  the  idea  of 
inserting  iron  rods  near  the  lower  surfaces  of  concrete  beams  to 
take  up  the  tensional  stresses,  and  in  company  with  Dr.  David 
Kirkaldy  of  London,  he  made  some  tests  and  published  his  very 
valuable  conclusions  in  1877. 


634 


BUILDING  CONSTRUCTION.  (Ch.  X) 


In  the  United  States  the  earhest  example  of  a  reinforced  build- 
ing was  the  building  erected  in  1875,  near  Port  Chester,  N.  Y.,  by 
Mr.  W.  E.  Ward.  In  this  structure  all  the  exterior  and  interior  walls, 
floor-beams,  roof,  cornices,  etc.,  were  made  entirely  of  concrete, 
reinforced  with  light  iron  beams  and  rods. 

The  early  development  of  the  new  system  took  place  in  this 
country  in  California,  where  the  pioneer  experimenters  were  H.  P. 
Jackson,  E.  L.  Ransome  and  G.  W.  Percy.  In  1877  Mr.  Jackson 
applied  Mr.  Hyatt's  invention  to  building  construction,  using  thin 
iron  blades,  set  horizontally  on  edge  with  round  iron  cross  wires  for 
the  reinforcement.  In  1884  and  1885  Ransome  built  a  warehouse, 
a  few  years  later  a  factory  building,  the  building  of  the  California 
Academy  of  Science  in  1888  and  1889  and  the  Museum  building 
of  the  Leland  Stanford  Junior  University  in  1892.  (See  Article 
527.)  The  last  two  buildings  mentioned  were  designed  by  Mr. 
Percy.  Ransome  used  square-section  bars  of  iron  and  steel  for 
his  reinforcements. 

Edwin  Thacher  and  F.  von  Emperger  also  were  among  the 
earliest  constructors  in  reinforced  concrete  in  the  United  States, 
doing  much  to  introduce  the  system,  especially  in  the  building  of 
bridges. 

525.  USES  OF  REINFORCED  CONCRETE  CONSTRUC- 
TION.— While  the  improvement  in  reinforced  concrete  construc- 
tion has  been  rapid  during  the  past  twenty  years,  it^is  since  about  the 
year  1896  that  its  development  has  been  particularly  remarkable. 
It  is  now,  in  1908,  looked  upon  by  architects  and  engineers  generally 
as  a  form  of  construction  which  is  safe,  if  properly  designed  and 
conscientiously  executed,  and  which  has  a  constantly  widening  field 
of  usefulness. 

The  constants  necessary  in  calculations  for  different  stress  resist- 
ances have  not  yet  been  determined  with  sufficient  definiteness,  but 
very  careful  research  is  being  made  in  this  direction.  What  may 
be  called  a  "common  practice"  may  be  said  to  have  been  established 
in  some  details,  and  for  much  design  work  many  rational  principles 
are  at  hand. 

It  is  the  general  opinion  of  engineers  and  investigators  that 
''good  practice"  in  reinforced  concrete  construction  will  be  estab- 
.lished  at  no  very  distant  time. 

Various  uses  of  reinforced  concrete  in  building  and  engineering 


REINFORCED  CONSTRUCTION.  635 


'construction  have  been  mentioned  in  Article  497,  in  connection  with 

concrete  in  general;  and  in  Article  514  were  given  some  early 
examples  of  mass  concrete  construction. 

Reinforced  concrete  construction  is  advantageous  to  varying 
degrees  in  different  types  of  structures.  Some  of  the  most  important 
of  these  types  are  mentioned  in  this  article,  and  in  the  following 
article  the  advantages  accompanying  its  use  in  their  design. 

For  this  purpose  the  different  types  of  structures  may  be  conven- 
iently classified  as  follows:*  (i)  Buildings,  (2)  Culverts  and  Small 
Girder  Bridges,  (3)  Retaining-walls,  Dams  and  Abutments,  (4) 
Arch  Bridges,  (5)  Reservoir  Walls,  Floors  and  Roofs,  (6)  Con- 
duits and  Pipe  Lines,  (7)  Elevated  Tanks,  Bins,  etc.,  (8)  Chimneys 
and  Towers,  (9)  Piles,  Railroad  Ties,  etc. 

526.  ADVANTAGES  OF  REINFORCED  CONCRETE  IN 
CONSTRUCTION. — For  Buildings. — Used  now  throughout  for 
all  parts;  especially  adapted  to  floor  slabs,  spread-footings  in  foun- 
dations, for  which  it  is  cheaper  than  I-beam  footings  imbedded  in 
concrete ;  and  used  with  constantly  increasing  skill  and  success  for 
beams,  girders  and  columns. 

For  Culverts  and  SinaH  Girder  Bridges. — Simpler  and  more 
economical  than  arches  of  masonry  and  more  durable  than  bridges 
of  steel. 

For  Retaining-walls,  Dams  and  Abutments. — Frequently  cheaper 
than  ordinary  masonry  construction ;  adapted  to  a  more  economical 
type  of  design,  such  as  reinforced  concrete  cantilever  beams,  for 
example,  and  thus  developing  the  full  compression  strength  of  the 
material  used ;  not  dependent  upon  weight  alone  to  resist  lateral 
thrust;  has  whatever  metal  is  used  thoroughly  covered  and  pro- 
tected from  corrosive  agencies,  which  an  all-steel  frame  has  not. 

For  Arch  Bridges. — Possesses  fewer  advantages  or  economies 
over  ordinary  masonry  construction,  because  the  prevailing  stresses 
are  principally  compressive ;  reinforcements  useful  only  to  prevent 
cracks  or  to  resist  comparatively  slight  flexture  stresses  caused  by 
moving  loads. 

For  Reservoir  Walls,  Floors  and  Roofs. — Well  adapted  because 
lighter  in  design,  and  probably  as  durable  as  ordinary  masonry. 

For  Conduits  and  Pipe  Lines. — Well  adapted  to  large  sewers  and  « 


*  See  "Principles  of  Reinforced  Concrete  Construction,"  by  Turneaure  and  Maurer, 
in  which  treatise  there  is  an  excellent  treatment  of  the  subject. 


636  BUILDING  CONSTRUCTION.  (Ch.  X> 


water-conduits,  and  also  occasionally  used  for  pipe  lines  and  tanks, 
under  pressure. 

For  Elevated  Tanks,  Bins,  etc. — Durable  and  well  suited  to  resist 
the  lateral  pressure  against  walls  and  heavy  loads  on  floors,  and 
often  employed  in  the  construction  of  entire  structures  ot  this  kind. 

For  Chimneys  and  Towers. — More  economical  in  design  and 
more  definite  in  stress  calculations  than  brick  and  stone  construction 
because  of  its  monolithic  character. 

For  Piles,  Railroad  Ties,  etc. — Valuable  substitute  for  wood  in 
piles,  especially  when  used  where  they  would  not  be  always  entirely 
under  water;  possess  several  advantages  over  wood  or  steel  for 
railroad  ties. 

527.  EARLY  EXAMPLES  OF  REINFORCED  CONCRETE 
CONSTRUCTION.— Ransome  Concrete  Floors.— Mr.  E.  L. 
Ransome  patented  his  improvements  in  1884,  and  after  that  time 
they  were  extensively  used,  especially  in  San  Francisco. 

The  Ransome  concrete  floors  were  made  in  two  forms — flat,  as. 
shown  in  Fig.  487,  and  recessed,  or  panelled,  as  shown  in  Fig.  488. 
These  floors  have  been  used  for  spans  up  to  34  feet.  No  floor  beams 
were  required,  the  floor  being  self-supporting  from  wall  to  wall 
(when  the  building  was  not  more  than  30  feet  wide),  or  from  wall 
to  girder.  The  great  strength  of  these  floors  was  fully  demon- 
strated by  actual  use  in  many  heavy  warehouses  in  various  portions 
of  California,  as  well  as  in  many  other  buildings. 

A  section  of  a  flat  floor  in  the  California  Academy  of  Science, 
15  by  22  feet,  was  tested  in  1890  with  a  uniform  load  of  415  pounds 
per  square  foot  and  the  load  left  in  place  for  one  month.  The 
deflection  in  the  middle  of  the  22-foot  span  was  only  ys  of  inch. 
It  was  estimated  by  the  architects  that  the  saving  at  that  time  by 
using  this  construction  throughout  the  building,  over  the  ordinary 
use  of  steel  beams  and  hollow  tile  arches  of  the  same  strength,  and 
with  similar  cement-finished  floors  on  top,  amounted  to  fifty  cents 
per  square  foot  of  floor. 

The  flat  construction  shown  in  Fig.  487  was  the  best  adapted  of 
the  two  for  office-buildings,  hotels,  etc.,  although  the  panelled  floor 
shown  in  Fig.  488  had  much  the  greater  strength  for  the  same 
amount  of  material.  The  latter  construction  was  used  in  several 
warehouses  in  California  without  the  use  of  any  steel  or  iron  beams 
or  girders,  and  supported  very  heavy  loads  for  many  years. 


REINFORCED  CONSTRUCTION.  637 


The  Lcland  Stanford  Junior  Museum,  at  Palo  Alto,  California. 
— This  very  large  and  costly  building,  mentioned  before  in  Article 
524,  was  also  constructed  entirely  of  concrete.    It  was  built  on  the 


Fig.  4S7.     Ranconie  Reinforced  Concrete  Floor.     Early  Flat  Form. 


Ransome  system,  using  twisted  iron  rods  imbedded  in  the  concrete 
to  give  tensile  strength  where  required. 

The  following  description  of  this  building,  written  some  time  aga 


Fig.  488.     Ransome  Reinforced  Concrete  Floor.     Early  Panelled  Form. 

by  the  architect,  ]\Ir.  Geo.  W.  Percy,  gives  an  idea  of  the  method 
of  construction  then  employed  and  also  of  the  cost  in  1892,  and  is. 
interesting  for  purposes  of  comparison  with  methods  of  construc- 
tion used  to-day. 

"This  building  was  designed  to  have  dressed  sandstone  for  the  external 
walls,  backed  up  with  brick,  and  to  have  brick  partitions  with  concrete  floors. 
Owing  to  the  great  cost  of  stonework,  it  was  decided  to  build  the  walls  of 
cemfent  concrete,  colored  to  match  the  sandstone  used  in  the  other  University- 
buildings,  and  to  carry  out  the  classic  design  first  adopted.    This  led  to 


.638 


BUILDING  CONSTRUCTION, 


(Ch.  XX 


making  the  entire  structure,  walls,  partitions,  floors,  roof  and  dome  of  con- 
crete,  making  it,  in  that  respect,  a  unique  building. 

"Having  some  knowledge  of  the  disadvantages  and  defects  natural  to  a 
monolithic  building,  such  as  result  from  the  shrinkage  and  the  expansion  and 
contraction  of  walls,  floor  and  roof,  several  new  experiments  were  tried  to 
overcome  them,  with  varying  results  of  success  and  failure.  It  was  thought 
to  overcome  the  cracking  of  walls  by  inserting  sheets  of  felting  through  the 
walls,  following  the  lines  of  the  joints  as  near  as  practicable  on  each  side  of 
the  windows.  The  lapping  bond  of  the  concrete,  however,  proved  too  strong 
to  allow  the  cracking  to  follow  these  joints;  in  most  cases  the  weakest  points 
were  found  at  the  openings,  and  small  cracks  appeared  from  window  head  to 
sills  above. 

"Joints  were  formed  through  the  floors  about  15  feet  apart  and  in  most 
cases  the  cracking  followed  these  •  joints  and  was  confined  to  them.  To 
prevent  the  possibility  of  moisture  penetrating  through  the  walls,  and  also  to 
render  them  less  resonant,  hollow  spaces  5  inches  in  diameter  were  molded 
in  the  walls  within  2  inches  of  the  inside  face,  and  with  about  2  inches  of 
concrete  between  them.  These  are  successful  for  the  primary  object,  and 
partially  so  for  the  secondary. 

"The  roof  being  the  greatest  innovation,  and  the  first  attempt  known  to  the 
writer  of  forming  a  finished  and  exposed  roof  entirely  in  concrete,  required 
the  greatest  care  and  consideration.  The  result  in  form  and  appearance  is 
shown  in  Fig.  489,  A  and  B,  and  may  be  described  as  follows  :  The  roof  is 
supported  on  iron  trusses  10  feet  on  centers,  and  has  a  pitch  of  20  degrees. 
The  horizontal  concrete  beams  rest  on  the  iron  rafters,  and  with  the  half 
arches  form  the  horizontal  lines  of  tiles  about  2  feet  6  inches  wide,  with  the 
joints  lapping  2  inches  and  a  strip  of  lead  inserted  as  shown.  Vertical  joints 
are  made  through  the  concrete  over  each  rafter  with  small  channels  on  each 
side.  These  joints  and  channels  are  covered  with  the  covering  tiles  shown 
on  drawings,  and  similar  rows  of  covering  tiles  are  placed  2  feet  6  inches  apart 
over  the  entire  roof,  thus  forming  a  perfect  representation  of  flat  Grecian 
tile  or  marble  roof.  Notwithstanding  the  precautions  taken,  this  roof  pre- 
sented several  unexpected  defects.  The  most  serious  proved  to  be  in  the 
Venetian  red  used  for  coloring  matter  and  mixed  with  the  cement.  This 
material  rendered  the  covering  tiles  absolutely  worthless,  many  of  them 
slacking  like  lumps  of  lime,  and  all  were  condemned  and  remade.  The  same 
material  injured  the  general  surface  of  the  roof,  rendering  it  porous  and 
necessitating  painting.  The  roof  over  the  central  pavilion  being  hidden  behind 
parapets,  is  made  quite  flat  and  covered  with  asphaltum  and  gravel  over  the 
concrete.  This  roof,  with  its  low,  flat  dome,  is  without  question  the  largest 
horizontal  span  in  concrete  to  be  found  anywhere  on  earth,  being  46  feet  by  56 
feet,  the  flat  dome  having  all  its  ribs  and  rings  of  concrete,  with  the  panels 
or  coffers  filled  with  i-inch  thick  glass  and  weighing  about  80,000  pounds." 

Fig.  490  show^s  an  interior  view  of  this  dome  and  the  hallway  and 
corridors  beneath.    All  the  construction  shown  in  this  view  is  of 


REINFORCED  CONSTRUCTION. 


639 


concrete.  In  the  first  story  the  walls  are  cased  with  marble  slabs 
and  above  they  are  finished  with  plaster. 

This  ^luseum  building,  as  well  as  the  building-  of  the  California 
Academy  of  Science,  withstood  the  shocks  of  the  great  earthquake 
remarkably  well ;  and  careful  examinations  showed  that  the  former 
resisted  the  destructive  tendencies  better  than  did  the  two  brick 
annexes  adjoining  It  covers  21,000  feet  and  contains  over 
1,100,000  cubic  feet  of  space.  It  required  about  360,000  cubic  feet 
of  concrete,  and  was  completed  in  seven  months  from  the  com- 
mencement of  the  foundations. 


The  cost  of  the  building  per  cubic  foot,  including  marble  stairs 
and  wainscoting,  cast-iron  window  frames  and  sashes  and  other 
parts  to  correspond,  was  about  eighteen  cents,  which  is  a  very  low 
figure  for  a  thoroughly  substantial  and  fire-proof  building. 

Other  important  buildings  which  were  executed  in  concrete  about 
this  time,  or  soon  after,  in  the  vicinity  of  San  Francisco  and  built 
according  to  the  Ransome  system,  were  the  Girls'  Dormitory  at  the 
Leland  Stanford  Junior  University  (a  three-story  building  com- 
pleted in  ninety  days  from  the  time  the  plans  were  ordered),  the 
Science  and  Art  building  and  Mills  College ;  also  the  Torpedo  Sta- 
tion on  Goat  Island,  80  by  250  feet,  and  an  addition  to  the  Borax 
Works  at  Alameda.  In  the  latter  the  walls,  interior  columns  and 
all  floors  were  of  concrete,  and  were  said  to  be  rem.arkable  for 
lightness  of  construction  and  great  strength. 

The  Alabama  Apartments,  Buffalo,  N.  Y . — Belonging  to  the  early 
history  of  reinforced  concrete  hotels  and  apartment-houses  in  the 
United  States  may  be  mentioned  the  Alabama  apartment-house,  at 
Bufifalo,  N.  Y.,  Mr.  Carlton  Strong,  architect.    This  building  is  60 


Fig.  489.     Roof  Construction  of  Dome  Shown  in  Fig.  490. 


'640  BUILDING  CONSTRUCTION..  (Ch.  X) 

by  i8o  feet  in  plan  and  six  stories  in  height,  with  all  walls,  floors 
and  partitions  built  of  concrete,  and  it  will  be  interesting-  and 
useful  to  present  a  few  of  the  details  of  its  construction,  in  order 
that  any  differences  from  those  of  similar  buildings  erected  to-day 
mav  be  observed. 


Fig.  490.    Dome  and  Hallway  of  Leland  Stanford  Junior 
Museum,  Palo  Alto,  Cal. 


It  was  begun  in  1894  and  finished  in  1896. 

The  general  plan  of  the  wall  and  floor  construction  is  shown  in 
Fig.  491,  which  represents  a  partial  section  at  the  level  of  the  third 
floor 

The  whole  thickness  of  the  wall  is  24  inches  from  top  to  bottom, 
the  inner  portion  being  2  inches  thick  for  the  whole  height.  The 
outer  portion  is  8  inches  thick  in  the  first  story,  diminishing  by  I. 
inch  in  each  story. 

Vertical  twisted  rods  were  built  in  the  walls,'  as  shown  in  the 
iigure,  and  they  were  spaced  about  15  feet  apart,  lengthwise  of  the 


REINFORCED  CONSTRUCTION.  641 


wall.  Opposite  these  vertical  rods  the  withes  are  3  inches  thick ; 
elsewhere  inches  thick.  In  each  withe  were  built  ^-inch  twisted 
rods,  extending  across  the  wall  and  placed  12  inches  apart  verti- 
cally. At  each  floor  level  ^-inch  horizontal  bars  were  imbedded  in 
the  walls  as  shown.  These  twisted  steel  bars  tied  the  walls 
together  in  all  directions,  while  the  shape  of  the  sections  of  the 


Fig.  491.    Wall  and  Floor  Construction,  Alabama  Apartment-house,  Buffalo,  N.  Y. 


wall  gave  the  greatest  stability  with  the  least  amount  of  material. 
The  spaces  in  the  walls  were  stopped  at  each  floor  level,  except  that 
for  purposes  of  smoke  flues  or  ventilation  some  of  them  were  more 
or  less  continuous. 

The  floors  were  built  according  to  the  Ransome  system,  with 
concrete  and  twisted  rods.  Most  of  the  floors  were  of  the  panelled 
construction  shown  in  Fig.  488,  although  some  portions  were  flat, 
and  of  the  type  shown  in  Fig.  487. 


642 


BUILDING  CONSTRUCTION. 


(Ch.  X> 


The  partitions  also  were  constructed  of  concrete,  with  twisted 
rods,  and,  being  monoHthic,  added  at  the  time  greatly  to  the  stiff- 
ness of  the  building. 

Most  of  the  concrete  used  was  made  in  the  proportions  of  i 
part  of  Portland  cement  to  6  parts  of  aggregate. 

The  contractors  stated  at  the  time  that  the  average  cost  of  the 
walls  was  twenty-five  cents  per  square  foot  of  outside  surface. 

Other  Comparatively  Early  Examples  of  Reinforced  Concrete 
Construction — The  following  is  a  partial  list  of  some  additional 
buildings  of  earlier  date  erected  with  walls,  floors  and  partitions 
of  reinforced  concrete  with  the  Ransome  system  of  construction: 

Fifteen-story  office-building,  Washington,  D.  C. 
St.  James'  Church,  Brooklyn,  N.  Y. 
Willard  Parker  Hospital  building,  New  York  City. 
Court-house  and  jail,  Mineola,  Long  Island,  N.  Y. 
Grandstand,  Cincinnati,  Ohio. 

Six  dry-kilns  and  two  factories  for  the  Singer  Manufacturing  Company, 
Cairo,  111. 

Twenty-four  dry-kilns,  pattern  house  and  oil  house,  South  Bend,  Ind. 

Four-story  refineries  for  the  Pacific  Coast  Borax  Company,  Bayonne,  N.  J. 

Factory  for  the  Farley  Duplex  Magnet  Company,  Jersey  City,  N.  J. 

Factory  for  the  Central  Lard  Company,  Jersey  City,  N.  J. 

Warehouse  for  the  Pacific  Coast  Borax  Company,  Bayonne,  N.  J 

Two  130-feet  chimney  stacks  at  South  Bend,  Ind.,  and  one  loo-feet  stack 
at  Jersey  City,  N.  J. 

The  Ransome  &  Smith  Company  gave  the  cost  of  factory  building  construc- 
tion between  1896  and  1900,  under  their  system,  at  about  7  cents  per  cubic  foot. 

2.    GENERAL  THEORY  AND  DESIGN. 

•528.  GENERAL  CONSIDERATIONS.— With  discussions  on. 
the  theory  of  reinforced  concrete  design,  the  general  theory  of 
the  flexure  of  beams,  the  theory  of  columns,  and  the  mathematical 
derivations  of  various  formulas,  this  book  is  not  concerned,  except 
in  a  very  general  way ;  and  the  reader  is  referred  to  the  many 
excellent  treatises  and  hand-books  now  available  on  these  subjects. 

As  the  subject  of  this  work  is  ''Building  Construction,"  only  those 
phases  are  discussed  which  relate  especially  to  materials  and  con- 
struction. General  and  brief  necessary  references  are  made  to  the 
general  principles  of  reinforced  concrete  design,  and  to  those  gen- 
eral principles  of  the  mechanics  of  materials  upon  which  this  system 
of  construction  depends ;  but  full  mathematical  and  mechanical  dis- 


THEORY  AND  DESIGN, 


643 


cussions  are  purposely  omitted  and  only  these  general  references 
included. 

It  has  seemed  desirable,  however,  in  this  connection,  in  this  part 
of  the  chapter  on  a  subject  of  such  general  importance  and  interest, 
to  give  some  simple  and  approved  working  formulas  for  reinforced 
concrete  beams,  slabs  and  columns,  with  brief  explanations  and 
with  the  accompanying  tables  of  constants,  etc.,  necessary  for  their 
use.* 

529.  PROPERTIES  OF  THE  MATERIALS.— Reinforced 
concrete  is  not  a  homogeneous  material  but  a  compound  material, 
and  a  reinforced  concrete  beam  is  a  compound  beam.  In  a  design 
where  two  or  more  materials,  such,  for  example,  as  concrete  and* 
steel,  are  combined  in  the  same  member  the  stresses  in  the  different 
materials  depend  not  only  upon  the  superimposed  loads,  but  also 
upon  the  elastic  properties  of  the  materials.  A  knowledge  of  these 
elastic  properties  is  therefore  as  necessary  as  a  knowledge  of  those 
properties  which  relate  to  strength  alone. 

The  concrete  materials  for  concrete  work  in  general  have  already 
been  considered  in  general,  as  to  their  nature  and  strength,  and  also 
as  to  their  elastic  properties  involving  the  modulus  of  elasticity 
and  the  elastic  limit. 

The  reinforcing  materials  are  considered  further  on. 

530.  STRESSES  IN  DIFFERENT  KINDS  OF  REIN- 
FORCED CONCRETE  STRUCTURAL  MEMBERS.— For  pur- 
poses of  convenience  structural  members  are  usually  classified  as 
(i)  Tension  Members,  (2)  Compression  Members  and  (3)  Beams. 
This  classification  is  based  on  the  character  of  the  forces  resisted, 
and  the  stresses  developed,  namely,  simple  tension,  simple  com- 
pression and  simple  bending,  respectively. 

Tension  or  compression  usually  accompanies  bending  or  flexure,, 
and  there  are  produced  what  are  termed  combined  stresses  of  bend- 
ing and  tension,  or  of  bending  and  compression. 

Reinforced  concrete  is  not  employed  for  plain  tension  members. 


*  In  this  instance  the  formulas  and  tables  referred  to  are  the  same  as  used  in  Kid- 
ned's  "Architect's  and  Builder's  Pocket-Book"  in  Chapter  XXIV,  written  by  Mr.  Rudolnli 
P.  Miller.  The  reader  is  referred  to  this  chapter;  and  for  fuller  discussions  of  the 
mechanical  side  of  building  construction  in  general,  to  the  remaining  chapters  of  the 
"Pocket-Book." 

It  was  always  Mr.  Kidder's  desire  that  these  two  works  of  his  should  be  comple- 
mentary, and,  as  far  as  possible,  used  together,  each  supplementing  the  other;  "Building 
Construction  and  Superintendence"  dealing  especially  with  materials  and  constructive 
methods  and  the  "Architect's  and  Builder's  Pocket-Book"  dealing  principally  with\ cal- 
culations relating  to  the  strength  of  materials,  each,  however,  where,  convenience  demands^, 
it,  occasionally  overlapping  the  other. 


644 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


It  is  used  for  beams  and  girders,  in  which  both  plain  bending  and 
combined  stresses  may  be  studied ;  and  for  columns,  which  become 
compression  members,  but  which  may  be  investigated  for  flexure 
also.  The  flat  reinforced  concrete  slab  supported  on  four  sides  is 
usually  considered  as  a  special  case  of  the  beam. 

531.  NOTES  ON  THE  FLEXURE  OF  BEAMS.— The 
external  loads  and  reactions  on  a  beam  maintain  their  equilibrium 
by  means  of  internal  stresses  which  are  generated  in  it.  For  any 
cross-section  of  a  beam : 

(1)  The  sum  of  the  tensile  stresses  equals  the  sum  of  the  com- 
pressive stresses. 

(2)  The  resisting  shear  equals  the  vertical  shear. 

(3)  The  resisting  moment  equals  the  bending  moment. 

But  these  three  important  theoretical  laws  regarding  internal 
stresses  deduced  from  the  three  necessary  conditions  of  static 
equilibrium  are  not  alone  sufficient  for  the  full  investigation  of  the 
subject  of  the  flexure  of  beams,  and  recourse  must  be  had  to  experi- 
ence and  experiment. 

When  a  beam  deflects  one  side  becomes  concave  and  the  other 
convex,  the  approximately  horizontal  compression  stresses  being  on 
the  concave  side  and  the  tensile  stresses  on  the  convex  side. 

Fig.  492  shows  a  "simple  beam"  resting  on  two  supports,  loaded 
with  a  concentrated  load  L  in  the  middle  and  in  a  state  of  flexure. 
The  material  of  the  beam  near  the  upper  surface  will  be  in  com- 
pression and  that  near  the  lower  surface  in  tension,  as  indicated 
by  the  arrows. 

Fig.  493  shows  a  ''continuous  beam,"  resting  on  and  extending 
over  the  columns  C  and  D  and  resting  on  the  walls  A  and  B.  It 
is  loaded  with  a  concentrated  load  in  the  middle  of  the  middle  span, 
at  L.  The  material  of  the  beam  will  be  in  tension  at  P,  in  the 
lower  part  of  the  middle  span  and  for  a  distance  on  each  side  of 
the  middle,  and  will  be  in  tension  also  in  the  upper  part,  over  the 
two  columns  and  for  some  distance  on  each  side  of  them.  These 
tensional  stresses  are  indicated  by  the  arrows  at  P,  P^  and  P^- 
Compressive  stresses  will  be  developed  in  the  upper  part  of  the 
beam  in  the  middle  of  the  middle  span  and  in  the  lower  part  of 
the  beam  over  and  near  the  two  columns. 

In  the  simple  beam  in  Fig.  492  the  bending  moment  is  greatest 
in  the  middle  of  the  span,  under  the  load,  diminishing  in  value 


THEORY  AND  DESIGN. 


645 


toward  the  supports,  where  it  becomes  zero.  The  vertical  shear  is 
zero  under  the  load  and  equal  to  each  reaction  between  the  load 
and  either  support.  For  unsymmetrical  loads  the  greatest  vertical 
shear  is  equal  to  the  greater  reaction  and  is  at  that  support  at  which 
the  greater  reaction  occurs. 

In  the  continuous  beam  of  Fig.  493  there  is  a  maximum  positive 

 . 


Fig.  492.     Simple  Beam.     Load  in  Middle.  Tensile 
Stresses  in  Lower  Part. 

bending  moment  in  the  middle  of  the  middle  span,  under  the  load, 
and  maximum  negative  bending  moments  over  each  column  sup- 
port, with  shears  at  the  supports  as  well  as  elsewhere. 

Of  course  with  variations  in  kinds  of  loading  and  in  spans  and 
with  "restraint"  at  the  walls,  corresponding  variations  in  reactions, 
moments  and  shears  occur. 

The  "bending  moment"  for  any  cross-section  of  a  beam  is  the 
algebraic  sum  of  the  moments  of  all  the  external  forces  on  either 
.  side  of  the  section.  Those  on  the  left  of  the  section  are  usually 
taken. 

The  'Vertical  shear"  for  any  cross-section  is  the  name  given  to 


p. 

r 

P, 

.1 

— 1 

1 

p 

C  D 

Fig.  493.    Continuous  Beam.    Concentrated  Load.    Tensile  and  Compressive  Stresses. 

the  algebraic  sum  of  all  the  external  forces  on  either  side  of  the 
section.    The  forces  on  the  left  are  usually  taken. 

The  ''resisting  moment"  is  the  algebraic  sum  of  the  moments  of 
the  internal  horizontal  stresses  in  any  cross-section  with  reference 
to  a  point  in  that  section. 

The  "resisting  shear"  is  the  algebraic  sum  of  all  the  vertical  com- 
ponents of  the  internal  stresses  in  any  cross-section  of  the  beam. 


646 


BUILDING  CONSTRUCTION.  (Cn.  X> 


It  is  found  that  any  two  vertical  straight  Hnes  drawn  on  the  side 
of  a  beam  before  flexure  remain  straight  after  flexure,  but  are 
nearer  together  than  before  on  the  compressive  side  and  farther 
apart  on  the  tensile  side. 

From  the  above  data  the  following  additional  experimental  laws 
have  been  added  to  the  three  theoretical  laws  already  stated  in  the 
first  part  of  this  article : 

(4)  The  horizontal  fibers  on  the  convex  side  are  elongated  and 
those  on  the  concave  side  are  shortened,  while  near  the  middle 
depth  of  the  beam  there  is  a  ''neutral  surface"  which  is  unchanged 
in  length. 

(5)  The  elongation  or  shortening  of  any  fiber  is  directly  pro- 
portional to  its  distance  from  the  neutral  surface. 

(6)  In  beams  of  homogeneous  material  the  horizontal  stresses 
are  directly  proportional  to  their  distances  from  the  neutral  surface, 
provided*  all  unit-stresses  are  less  than  the  elastic  limit  of  the 
material. 

From  these  laws  is  deduced  the  following  important  theorem: 

(7)  In  beams  of  this  kind  the  neutral  surface  passes  through 
the  centers  of  gravity  of  the  cross-sections. 

Fig.  494  shows  the  ''lines  of  principal  stress"  in  a  beam  in  a  state 
of  flexure  under  loading.  By  combining  the  bending  movement 
stresses  with  the  shearing  stresses  at  the  various  points  of  a  beam,  • 
and  plotting  the  results,  curved  lines  of  so-called  ''principal  stress" 
are  drawn  as  shown.  In  the  middle  of  the  span  the  stress  lines  are 
horizontal  and  at  the  ends  vertical.  Resolving  these  stress  lines 
into  their  mechanical  components,  vertical  and  horizontal,  as  illus- 
trated in  Fig.  495  by  the  stepped  lines  at  the  section  AA,  it  is 
seen  that  the  horizontal  component  of  each  stress  increases  in  mag- 
nitude as  the  middle  of  the  span  is  approached,  reaching  a  maximum 
at  that  point.  The  magnitude  of  each  vertical  component  decreases 
toward  the  middle  of  the  span  and  reaches  its  maximum  at  the 
end  of  the  line  of  stress. 

This  figure  is  useful  in  designing  reinforced  concrete  beams,  and' 
in  locating  the  reinforcing  metal  in  the  proper  places  to  resist  the 
various  stresses,  and  as  far  as  possible  to  insure  an  equilibrium  of 
horizontal  and  vertical  forces  and  also  of  diagonal  forces  or  of 
their  horizontal  and  vertical  components. 

The  above  condensed  notes  are  given  in  order  to  assist  in  a 


THEORY  AND  DESIGN. 


647 


■clearer  understanding  of  the  terms  used  in  working  formulas,  tables, 
and  the  demands  of  building  laws  relating  to  reinforced  concrete 
construction. 

532.  NOTES  ON  REINFORCED  CONCRETE  BEAMS.— 
The  object  of  reinforcement  is  apparent  from  the  foregoing.  Con- 
crete being  comparatively  weak  in  tension  and  strong  in  com- 


Fig.  494.    Lines  of  Principal  Stress  in  a  Beam  in  a  State  of  Flexure. 


pression,  if  steel,  which  has  a  high  tensional  as  well  as  compressive 
strength,  is  placed  where  tensional  stresses  are  developed,  if  there 
is  sufficient  concrete  properly  placed  to  resist  the  compressive 
stresses,  if  the  reinforcement  is  arranged  generally  to  resist  the 
shearing  stresses,  and  if  the  compound  structural  member  can  be 
made  to  act  as  a  unit,  a  strong  and  economical  design  will  result. 

Fig.  496  is  an  illustration  of  the  simplest  form  of  reinforcing 
for  a  simple  beam  in  a  state  of  flexure  under  a  concentrated  load 
in  the  middle  of  the  span,  and  shows  the  effect  of  reinforcement 
in  increasing  the  strength.  These  two  8  by  12-inch  concrete  beams 
were  12  feet  long  and  were  loaded  as  indicated  until  failure  occurred. 


I 


Fig.  495.     Resolution  of  Principal  Stress  Lines  in  a  Beam. 


One  beam  was  of  plain  concrete,  without  reinforcement ;  the  other 
was  reinforced  as  show^n.  The  former  failed  with  a  load  of  2,500 
pounds,  the  latter  did  not  fail  until  the  loading  reached  29,000 
pounds,  showing  that  the  reinforcing  rods  had  increased  the  strength 
over  iiYz  times. 

Reinforcements  in  concrete  beams  vary  from  this  simple  form 
to  more  or  less  complicated  arrangements  of  the  metal ;  and  while 


648 


BUILDING  CONSTRUCTION.  (Ch.  X) 


details  of  procedure  vary  with  different  systems,  the  fundamental 
basis  of  all  reinforced  concrete  design  is  the  determination  of  the 
proper  amount  and  arrangement  of  the  metal  necessary  to  resist 
the  tensional  stresses  and  of  the  concrete  to  resist  the  compressive 
stresses. 

533.  MANNER  OF  FAILURE  OF  REINFORCED  CON- 
CRETE BEAMS. — It  is  assumed  that  the  concrete  and  steel  adhere 
perfectly  and  deform  equally.    There  may  be  simple  adhesion,  or  a 


Fig.  496.     Comparative  Strength  of  Plain  and  Reinforced  Concrete  Beams. 


grip  from  roughened  or  deformed  bars,  or  an  anchorage  from 
a  bending  or  anchoring  at  the  ends. 

"A  reinforced  concrete  beam  tested  to  destruction  will  usually 
fail  in  one  of  three  ways : 

(1)  By  the  yielding  of  the  steel  at  or  near  the  section. of  maxi- 

mum bending  moment. 

(2)  By  the  crushing  of  the  concrete  at  the  same  place. 

(3)  By  a  diagonal  tension  failure  of  the  concrete  at  a  place 

where  the  shear  is  large."* 
There  are  also  minor  causes  of  failure,  such  as  the  slipping  of  the 
reinforcing  rods,  which  is  not  likely  to  occur,  and  such  as  the  shear- 
ing of  the  concrete  near  a  support  when  the  load  is  very  close  to  it. 
This  latter  failure  is  also  exceedingly  unlikely  to  occur,  as  the 


*  "Principles  of  Reinforced  Concrete  Construction."      Turneaure  and  Maurer. 


THEORY  AND  DESIGN. 


shearing  strength  of  concrete  for  true  ''vertical  shear"  is  sometimes 
shown  by  tests  to  be  nearly  one-half  its  crushing  strength. 

The  usual  so-called  "shearing"  failures  in  a  beam  are  in  reality 
**diagonal-tension"  failures,  for  which  tensile  strength  values  are  used. 

The  following  figures  illustrate  some  of  the  ways  in  which  rein- 
forced concrete  beams  begin  to  fail  when  loaded  to  destruction  :* 

Fig.  497  shows  a  typical  form  of  failure  of  a  reinforced  concrete 
beam  due  to  diagonal  tension. 

Fig.  498  shows  a  typical  form  of  failure  caused  by  the  splitting 
of  the  concrete  above  the  reinforcement. 

Fig.  499  shows  a  typical  form  of  tension  failure  when  the  full 
proportion  of  the  strength  of  both  the  concrete  and  the  steel  is 
developed,  the  diagonal-tensional  stresses  resisted,  and  the  steel 
tending  to  fail  by  tensional  stress.  A  reinforced  concrete  beam 
failing  in  this  manner  when  tested  to  destruction  indicates  that 
the  reinforcement  is  arranged  in  a  more  nearly  effective  manner 
than  in  the  beams  shown  in  the  first  two  figures. 

534.  DESIGN  OF  REINFORCED  RECTANGULAR 
BEAMS  AND  GIRDERS.— Different  formulas  have  been  proposed 
by  investigators  for  the  strength  of  reinforced  concrete  beams  based 
on  various  theoretical  considerations.  The  differences  among  them 
arise  principally  from  three  sources : 

(1)  The  method  of  applying  the  factor  of  safety;  some  engi- 

neers assuming  working  strengths  for  the  concrete  and 
steel,  with  which,  by  a  suitable  flexure  formr.1i,  the  safe 
load  is  directly  computed ;  and  others  computing  the 
breaking  load  of  the  beam  by  a  suitable  formula  and 
then  deciding  upon  the  safe  load  with  reference  to  this 
breaking  load. 

(2)  The  law  of.  distribution  of  the  compressive  fiber  stress  in 

the  concrete.  The  most  widely  used  flexure  formulas 
for  working  conditions  are  based  on  the  assumption  that 
the  stress-strain  curve  is  practically  straight  up  to  work- 
ing stresses.  When  the  curvature  of  this  curve  is  taken 
into  account,  it  is  generally  assumed  to  be  an  arc  of  a 
parabola,  some  taking  the  vertex  at  the  upper  end  of 
the  curve,  the  ultimate  strength  end,  and  others  taking^ 
it  beyond  that  point. 

*  Reproduced  from  "Desiening  Tables."  Courtesy  of  the  Gabriel  Concrete  Rein- 
forcement Company,  Detroit,  Mich. 


650 


BUILDING  CONSTRUCTION,  (Ch.  X) 


(3)  The  value  of  the  tensile  fiber  stress  in  the  concrete.  The 
residual  tension  in  the  concrete  is  seldom  allowed  for 
in  the  ultimate  resisting  moment  in  formulas,  the  almost 
universal  practice  being  to  neglect  it  entirely. 

A  dozen  different  diagrams  may  be  drawn  showing  different  dis- 

-y,  //////   .  V\V\\\ 

Fig.  497.    Failure  of  Reinforced  Concrete  Beam  by  Diagonal  Tension. 

tributions  of  fiber  stress  in  concrete  according  to  various  assump- 
tions and  also  as  many  different  formulas.* 

The  following  formulas  for  the  design  of  rectangular  beams  and 
girders  of  reinforced  concrete  give  results  closely  approximating 
those  from  actual  tests.  They  are  simple  in  form  and  have  been 
adopted  in  several  building  regulation  ^odes  in  this  country  and 
abroad. 

535.  ASSUMPTIONS  MADE  IN  FORMULAS  USED.— 
The  formulas  used  are  based  on  the  following  assumptions : 


Fig.  498.    Failure  of  Reinforced  Concrete  Beam  by  Splitting  of  Concrete. 

(1)  Sufficient  bond  between  the  concrete' and  steel  to  make  them 

act  together. 

(2)  A  plane  cross-section  before  flexure  remains  a  plane  after 

flexure  and  consequently  the  stress  and  strain  fdefor- 
mation)  in  any  fiber  are  directly  proportional  to  the 
distance  of  that  fiber  from  the  neutral  axis  of  the  cross- 
section. 

(3)  The  modulus  of  elasticity  of  the  concrete  remains  constant 

within  the  assumed  working  stresses. 


Fig.  499.    Ideal  Failure  of  Reinforced  Concrete  Beam  by  Steel  Tension. 

(4)  The  tensional  stress  is  resisted  entirely  by   the   steel,  the 

tensile  strength  of  the  concrete  not  being  considered. 
Fig.  500  shows  a  vertical  longitudinal  section  of  a  reinforced 

*  See  "Principles  of  Reinforced  Concrete  Construction,"  by  Turneaure  and  Maurer, 
Chapter  III,  Article  52. 


THEORY  AND  DESIGN. 


651 


concrete  beam  in  a  state  of  flexure  under  a  load.  The  vertical  line 
in  the  middle  is  the  trace  or  vertical  section  of  a  cross-section  of 
the  beam,  and  the  horizontal  broken  line  is  the  trace  or  vertical 
section  of  the  neutral  surface  of  the  beam.  The  neutral  axis  of  the 
cross-section  of  the  beam  is  a  vertical  section  of  the  neutral  surface 
of  the  beafn,  or  the  line  in  which  the  neutral  surface  intersects  the 
plane  of  the  cross-section,  and  it  appears  in  this  drawing  as  the 
point  of  intersection  of  the  vertical  and  horizontal  lines  referred 
to  above.  The  position  of  the  steel  reinforcement  is  shown  near 
the  lower  surface  of  the  beam.  The  shaded  triangle  above  the 
neutral  surface  line  is  the  graphical  representation  of  the  variation 
of  compressive  .stresses  on  a  cross-section.  The  total  compression 
on  the  cross-section  is  proportional  to  the  area  of  the  triangle,  the 


average  unit  compressive  fiber  stress  is  represented  by  the  average 
abscissa  of  the  triangle  and  the  resultant  compression  acts  through 
the  centroid  of  the  triangle  as  shown  by  the  horizontal  arrow. 

All  the  fibers  above  the  neutral  axis  of  the  cross-section  are  in 
compression,  and  the  resultant  of  the  tensional  stresses  is  at  the 
center  of  gravity  of  the  steel  reinforcement. 

By  using  these  assumptions  and  conditions  and  the  static  and 


experimental  laws  stated  in  Article  531,  the  proper  equations  may 
be  wriUen  and  the  formulas  deduced. 

536.  FORMULAS  FOR  REINFORCED  CONCRETE 
BEAMS.*— 


5"  =  the  allowable  tensile  working  unit-stress  in  the  steel 
C  =  the  allowable  compressive  working  unit-stress  in  the  extreme  fiber 
of  the  concrete. 
Es  —  the  modulus  of  elasticity  of  the  steel. 

Ec  =  the  modulus  of  elasticity  of  the  concrete  in  compression. 
r  =  the  ratio  of  the  modulus  of  elasticity  oi  the  steel  to  the  modulus  of 
elasticity  of  the  concrete,  or  — ^ 

*  See  footnote,  Article  528. 


Fig.   500,     Stress  Diagram.     Reinforced  Concrete  Beam. 


652 


BUILDING  CONSTRUCTION.  (Ch.  X)^ 


d  —  the  effective  depth  of  the  beam,  that  is,  the  distance  from  the  center 
of  gravity  of  the  steel  reinforcement  to  the  extreme  fiber  in  compression. 

X  =  the  ratio  of  depth  of  the  neutral  axis  from  the  extreme  fiber  in  com- 
pression to  the  effective  depth  of  the  beam,  and  is  a  number  less  than  unity. 

xd  —  the  distance  of  the  neutral  axis  from  the  extreme  fiber  in  compres- 
sion. 

b  =  the  width  of  the  beam.  * 

p  =  the  ratio  of  cross-section  of  the  steel  to  the  cross-section  of  the  beam, 
considering  the  beam  all  of  that  part  of  the  concrete  above  the  center  of 
gravity  of  the  steel. 

M  =  the  maximum  bending  moment  which  equals  the  resisting  moment  of 
the  beam  for  the  same  section. 

K  =:  a.  factor  used  for  simplification  of  the  formula.  This  factor  is  con- 
stant for  any  given  steel  and  concrete. 

For  beams  of  rectangular  cross-section. 

M^Kbd''  (10) 
the  value  of  K  being  determined  by  the  following: 

which  formula  can  be  deduced  from  the  laws  of  flexure  and  the  assumptions 
noted  above. 

In  the  use  of  this  formula  for  the  value  of  K  it  must  be  remembered  that 
the  ratio  of  5  to  C,  for  any  given  ratio  of  steel  to  concrete,  p,  is  a  constant, 
so  that  corresponding  values  of  5"  and  C  must  be  used.  This  ratio  p,  often 
spoken  of  as  the  "percentage  of  reinforcement,"  is  the  expression  in  the  first 
parentheses, 


(12) 


The  value  of  x  is  derived  from  the  expression 

x  =  rp(/l  +  4-l)  (13) 

Values  for  K  and  x  for  corresponding  values  of  p,  for  different  conditions 
fixed  by  the  building  authorities  of  different  cities,  are  given  in  Tables 
XXXVIII  and  XXXIX. 

TABLE  XXXVIIL 
Constants  for  Reinforced  Concrete  Beams  When  Ratio  of 

MODULUSES   Is  12. 
X  =  the  coefficient,  which,  when  multiplied  hy  d,  gives  the  position  of 
the  neutral  axis. 

K=  the  coefficient  for  determining  the  resisting  moment  in  M  =  Kbd^. 
c  =  the  extreme  fiber  stress  in  the  concrete. 
s  —  the  extreme  fiber  stress  in  the  steel. 


TABLE  XXXVIU.— Continued.  653. 


 p  

1 

K 

r    \    s  1 

K 

C 

K  1 

.OOOo 

! 

.104 

5.8 

11"; 

1  iCiAn) 

6.8 

ia5 

14(X)0 

7  7 

154 

160(:)0 

jmo 

.143 

11.4 

168 

13.3 

196 

224 

.OOlf) 

.172 

17.0 

209 

44 

19.8 

244 

22.6 

279 

.(1020 

.196 

22.4  . 

OIK 

44 

26.2 

286 

29.9 

327 

.002.") 

.217 

27.8 

o~« 
4io 

44 

32.5 

323 

37.1 

369 

,0080 

.235 

33.2 

•)U0 

44 

38.7 

357 

44.2 

409 

.0035 

.2-)l 

38.5 

44 

44.9 

390 

51.3 

446 

.0040 

.266 

43.8 

00  L 

44 

51.1 

421 

58.4 

481 

.0045  . 

.279 

49.0 

'lur 
00 1 

44 

57.1 

452 

63.3 

500 

15500 

.0050 

.291 

54.2 

4i<4  . 

44 

63.2 

481 

65.7 

14550 

.0055 

.303 

59.3 

436 

44 

68.1 

500 

13773 

68.1 

13775 

.0060 

.314 

64.4 

44 

70.3 

13083 

70.3 

13083 

.0085 

.;^25 

69.6 

loK) 

44 

72.5 

12500 

72.5 

1250O 

.0070 

.334 

74.2 

1  1  QOQ 

74.2 

11929 

74.2 

11929 

.0075 

.344 

76.2 

76.2 

11467 

76.2 

1146T 

.0080 

.a53 

77.9 

J  lUoU 

77.9 

11030 

77.9 

11030 

.0085 

.361 

79.4 

iUDiO 

79.4 

10618 

79.4 

1061» 

.0090 

.369 

80.9 

80.9 

10250 

80.9 

10250 

.0095 

.377 

82.4 

villi  L 

82.4 

9921 

82.4 

9921 

,0100 

.384 

83.7 

youu 

83.7 

9600 

83.7 

9600 

.0105 

.392 

85.2 

UQQQ 

yooo 

85.2 

9333 

85.2 

93;3a 

.0110 

.399 

86.5 

9068 

86.5 

9068 

86.5 

9068 

.0115 

.405 

87.6 

oou't 

87.6 

8804 

87.6 

8804 

.0120 

.412 

88.9 

oOoo 

88.9 

8583 

88.9 

8585 

.0125 

.418 

90.0 

OoDU 

90.0 

8360 

90.0 

8360 

.0130 

.424 

91.0 

91.0 

81.54 

91.0 

8154 

.0135 

.430 

92.1 

i.mo 

92  1 

7963 

92.1 

7963 

.0140 

.436 

93.2 

(  t  oD 

93.2 

7786 

93.2 

•  7786 

.0145 

.441 

94.0 

i  DUO 

94.0 

7603 

94.0 

7603 

.0150 

.446 

94.9 

i  iOO 

94.9 

7433 

94.9 

7433 

.0155 

.452 

96.0 

79Qn 

96.0 

7290 

96.0 

7290 

.0160 

.457 

96.8 

^^ 

71  1 
1  111 

96.8 

7141 

96.8 

7141 

.0165 

.462 

97.7 

11 

7<¥»n 

(<JUU 

97.7 

7000 

97.7 

7000 

.0170 

.467 

98.6 

Douo 

98.6 

6868 

98.6 

6868 

.0175 

.471 

99.3 

A79Q 

99.3 

6729 

99.3 

6729 

.0180 

.475 

99.9 

Oovi 

99.9 

6597 

99.9 

6597 

.0185 

.480 

100.8 

,1, 

6486 

100.8 

6486 

100.8 

648(>. 

.0190 

.4h'5  • 

101.7 

101.7 

6382 

101.7 

6382 

.0195 

.489 

102.3 

D<JOi7 

102.3 

6269 

102.3 

62n» 

.0200 

.493 

103.0 

DiOO 

103.0 

6153 

103.0 

6163 

.0005 

.104 

8.7 

1 1  0 

ioUUU 

9.7 

192 

2(J000 

10.6 

212 

22000 

.0010 

.143 

17.1 

252 

19.0 

280 

20.9 

308 

.0015 

.172 

25.4 

ol't 

28.3 

349 

31.1 

384 

.0020 

.196 

33.6 

QK7 
00  i 

44 

37.4 

408 

41.1 

449 

.0025 

.217 

41.8 

ii!y 

44 

46.4 

461 

60.3 

SIX) 

21700 

.0030 

.235 

49.8 

44 

54.3 

500 

19583 

54.2 

19583 

.0035 

.251 

57.5 

500 

1  7QOQ 

57.5 

17929 

57.5 

17929 

.0040 

.266 

60.6 

1  RiiOK. 
100(J.J 

60.6 

16625 

60.6 

it 

1662,5 

.0045 

.279 

63.3 

1  KK{V\ 

63.3 

15500 

03.3 

1550O 

.0050 

.291 

65.7 

65.7 

14550 

65.7 

14550 

.0055 

.303 

68.1 

101  10 

68.1 

13773 

68.1 

13773 

.0060 

.314 

70.3 

loUoO 

70.3 

13083 

70.3 

13083 

.0065 

.325 

72.5 

72.5 

12500 

72.5 

12500 

.0070 

.334 

74.2 

1  1  QOQ 

74.2 

.  11929 

74.2 

11929 

.0075 

.344 

76.2 

1140/ 

76.2 

11467 

76.2 

11467 

.0080 

.353 

77.9 

77.9 

11030 

77.9 

11030 

.0085 

.361 

79.4 

1 0(51  8 

79.4 

10618 

79.4 

10618 

.0090 

.369 

80.9 

J  U<i.Jl ) 

80.9 

1025!) 

80.9 

10250 

.0095 

.377 

82.4 

82.4 

9921 

82.4 

9921 

.0100 

.384 

83.7 

n 

9600 

83.7 

9600 

83.7 

9600 

.0105 

.392 

85.2 

85.2 

9333 

85.2 

9333 

.0110 

.399 

86.5 

41 

QHRa 

yuDo 

86.5 

9068 

86.5 

9068 

.0115 

.405 

87.6 

j4 

880/) 
oou't 

87.6 

8804 

87.6 

8804 

.0120 

'  .412 

88.9 

8(^UQ 

OOoo 

88.9 

8583 

88.9 

8583 

.0125 

.418 

90.0 

44 

»OOU 

90.0 

8360 

90.0 

8360 

.0130 

.424 

91.0 

44 

81  KA 

91.0 

8154 

91.0 

8154 

.0135 

.430 

92.1 

7963 

92.1 

7963 

92.1 

7963 

.0140 

.436 

93.2 

778ft 
(  /oD 

93.2 

7786 

93.2 

778r> 

.0145 

.441 

94.0 

7603 

94.0 

7603 

94.0 

7603 

.0150 

.446 

94.9 

7433 

94.9 

7433 

94.9 

7433 

.0155 

.452 

96.0 

7290 

96.0 

7290 

96.0 

7290 

.0160 

.457 

96.8 

7141 

96.8 

7141 

96.8 

7141 

.0165 

.462 

97.7 

7000 

97.7 

7000 

97.7 

70(X) 

.0170 

.467 

98.6 

6868 

98.6 

6868 

98.6 

6868 

.0175 

.471 

99.3 

6729 

99.3 

6729 

99.3 

6729 

.0180 

.475 

99.9 

6597 

99.9 

6597 

99.9 

6597 

.0185 

.480 

100.8 

6486 

100.8 

6486 

100.8 

6486 

.0190 

.485 

101.7 

6382 

101.7 

6382 

101.7 

638^ 

.0195 

.489 

102.3 

6269 

102.3 

6269 

102.3 

6269 

.0200 

.493 

103.0 

6163 

103.0 

6163 

103.0 

6163. 

654  BUILDIXG  COXSTKUCTION.  (Ch.  X) 

TABLE  XXXIX. 

Constants  for  Reinforced  Concrete  Beams  When  Ratio  of 

MoDULusES  Is  15. 

For  r  =^  7^  =  15 


p 

X 

A 

C 

A 

C 

S 

K 

C 

.0005 

.115 

5.8 

104 

12000 

6.7 

122 

14000 

7.7 

139 

16000' 

.0010 

.159 

ii;4 

151 

13.3 

176 

15.2 

201 

.0015 

.191 

16.9 

188 

19.7 

220 

22.5 

251 

.0020 

.217 

22.3 

221 

26.0 

258 

29.7 

295 

.0025 

.239 

27.6 

251 

32.2 

293 

36.8 

335 

.0030 

.258 

32.9 

279 

38.4 

326 

43.9 

372 

.0035 

.276 

38.1 

304 

44.5 

355 

50.9 

406 

n. 

.0040 

.292 

43.3 

329 

50.6 

384 

57.8 

438 

.0045 

.306 

48.5 

353 

56.6 

412 

64.7 

471 

.0050 

.320 

53.6 

375 

62.6 

438 

1  71.5 

500 

.0055 

.332 

58.7 

398 

68.5 

464 

73.8 

15091 

.0060 

.344 

63.8 

419 

74.4 

488 

76.2 

14333 

.0065 

.355 

68.8 

439 

78.3 

500 

13654 

78.3 

13654 

.0070 

.365 

73.8 

460 

80.1 

13036 

80.1 

13036 

...0075 

.375 

78.8 

480 

82.0 

12500 

82.0 

1250O 

..0080 

.384 

83.7 

500 

83.7 

12000 

83.7 

12000 

.0085 

.393 

85.4 

11559 

85.4 

11559 

85.4 

11559 

.0090 

.402 

87.0 

11167 

87.0 

11167 

87.0 

11167 

.0095 

.410 

88.5 

10789 

88.5 

10789 

88.5 

10789 

.0100 

.418 

89.9 

10450 

89.9 

10450 

89.9 

10450 

.0105 

.425 

91.2 

10119 

91.2 

10119 

91.2 

10119 

.0110 

.433 

92.6 

9841 

92.6 

9841 

92.6 

9841 

.0115 

.440 

93.9 

9565 

93.9 

9565 

93.9 

9565 

.0120 

.446 

94.9 

9292 

94.9 

9292 

94.9 

9292 

.0125 

.453 

96.2 

9060 

96.2 

9060 

96.2 

9060 

.0130 

.459 

97.2 

8827 

97.2 

8827 

97.2 

8827 

.0135 

.465 

98.2 

8611 

98.2 

8611 

98.2 

8611 

.0140 

.471 

99.3 

8411 

99.3 

8411 

99.3 

8411 

.0145 

.477 

100.3 

8224 

100.3 

8224 

100.3 

8224 

-  .0150 

.483 

101.3 

8050 

101.3 

80.50 

101.3 

8050 

.0155 

.488 

102.2 

7871 

102.2 

7871 

102.2 

7871 

.0160 

.493 

103.0 

7703 

103.0 

7703 

103.0 

7703 

.0165 

.498 

103.8 

7545 

103.8 

7545 

103.8 

7545 

.0170 

.503 

104.6 

7397 

104.6 

7397 

104.6 

7397 

.0175 

.508 

105.5 

7257 

105.5 

7257 

105.5 

7257 

.0180 

.513 

106.3 

7125 

106.3 

7125 

106.3 

7125 

.0185 

.518 

107.2 

7000 

107.2 

7000 

107.2 

7000 

.0190 

.522 

107.8 

6868 

107.8 

6868 

107.8 

6868 

.0195 

.527 

108.6 

6756 

108.6 

6756 

108.6 

6756 

.0200 

.531 

109.3 

6638 

109.3 

6638 

109.3 

6638 

.0005 

.115 

8.7 

157 

18000 

9.6 

174 

20000 

10.6 

191 

22m 

.0010 

.159 

17.1 

226 

18.^ 

252 

20.8 

277 

-0015 

.191 

25.3 

283 

28.1 

314 

30.9 

346 

.0020 

.217 

33.4 

332 

37.1 

369 

40.8 

406 

.0025 
.0030 

.239 

41.4 

377 

46.0 

.  418 

50.6 

460 

it 

.258 

49.3 

419 

54.8 

465 

58.9 

500 

21500 

.0035 

.276 

57.2 

457 

62.7 

500 

19714 

62.7 

19714 

.0040 

.292 

64.0 

493 

65.9 

18250 

65.9 

18250 

.0045 

.306 

68.7 

500 

17000 

68.7 

17000 

68.7 

17000 

.0050 

.320 

71.5 

16000 

71.5 

16000 

71.5 

16000 

.0055 

.332 

73.8 

15091 

73.8 

15091 

73.8 

15091 

.0060 

.344 

76.2 

14333 

76.2 

14333 

76.2 

14333 

.0U65 

.355 

78.3 

13654 

78.3 

13654 

78.3 

13654 

,0070 

.365 

80.1 

13036 

80.1 

13036 

80.1 

13036 

.0075 
.0080 

.375 

82.0 

12500 

82.0 

12500 

82.0 

12500 

.384 

83.7 

12000 

83.7 

12000 

83.7 

12000 

.0085 

.393 

85.4 

11559 

85.4 

11559 

85.4 

11559 

.0090 

.402 

87.0 

11167 

87.0 

11167 

87.0 

11167 

-.0095 

.410 

88.5 

10789 

88.5 

10789 

88.5 

10789 

.0100 

.418 

89.9 

10450 

89.9 

10450 

89.9 

10450 

THEORY  AND  DESIGN.  655; 
TABLE  XXXIX.— Continued, 


C0NST.\NTS   FOR   REINFORCED   CONCRETE   BeAMS   WhEN    RaTIO  OF" 

MODULUSES  Is  15. 


V 

X 

K 

C 

s 

K 

C 

s 

K 

c 

s 

.0105 

.425 

91.2 

m 

10119 

91.2 

500 

10119 

91.2 

5()0 

10119) 

.0110 

.433 

93.6 

9841 

93.6 

9841 

92.6 

9841 

.0115 

.440 

93.9, 

9565 

93.9 

9565 

93.9 

9565 

.0120 

.446 

94.9 

9292 

94.9 

9292 

94.9 

92952 

.0125 

.453 

96.2 

9060 

96.2 

9060 

96.2 

9060 

.0130 

.459 

97.3 

8837 

97.2 

8827 

97.2 

8827 

.0135 

.465 

98.2 

8611 

98.2 

8611 

98.2 

8611 

.0140 

.471 

99.3 

8411 

99.3 

8411 

99.3 

Ik 

8411 

.0145 

.477 

100.3 

8224 

100.3 

8224 

100.3 

8234. 

.0150 

.483 

101.3 

80,50 

101.3 

8050 

101.3 

805O> 

.0155 

.488 

102.2 

7871 

102.2 

7871 

102.2 

7871 

.0160 

.493 

103.0 

7703 

103.0 

7703 

103:0 

770a 

.0165 

.498 

I  103.8 

7545 

103.8 

7545 

103.8 

7545. 

.0170 

.503 

104.6 

7397 

104.6 

7397 

104.6 

7397 

.0175 

.508 

105.5 

7257 

105.5 

7257 

105.5 

7257 

.0180 

.513 

1  106.3 

7135 

106.3 

7135 

106.3 

7125 

.0185 

.518 

1  107.2 

7000 

107.2 

7000 

107.2 

7000* 

.0190 

.522. 

1  107.8 

6868 

107.8 

6868 

107.8 

6868. 

.0195 

.527 

1  108.6 

6756 

108.6 

6756 

108.6 

6750^ 

.0200 

.531 

109.3 

6638 

109.3 

6638 

109.3 

663& 

(For  Table  XL  see  next  page.) 


537.  DETERMINATION  OF  THE  SIZE  OF  RECTANGU- 
LAR REINFORCED  CONCRETE  BEAMS.— To  determine  the 
size  of  a  beam  required  for  any  particular  case,  formula  (10)  is 
put  into  the  form 

d=i/^  (14) 
r  Kb 

The  breadth  b  is  assumed,  M  is  the  maximum  bending  moment 
at  the  dangerous  section,  r,  C  and  6^  are  given  and  K  is  found 
either  by  using  formula  (11)  or  from  Tables  XXXVIII  and 
XXXIX.    The  equation  is  then  solved  for  the  depth  .d- 

As  there  are  numerous  correct  solutions  for  varying  ratios  of 
d  and  b,  it  frequently  happens  in  practice  that  several  trials  have 
to  be  made  to  satisfy  some  particular  structural  or  architectural 
requirements. 

538.  DETERMINATION  OF  THE  STRENGTH  OR 
DIMENSIONS  OF  REINFORCED  CONCRETE  SLABS.— 
The  formulas  given  for  beams  may  be  used  to  determine  the 
strength  or  dimensions  of  slabs.  Any  one  of  three  treatments  may- 
be employed : 


656 


BUILDING  COXSTRUCTION. 


(Ch.  X) 


(1)  Slab  considered  a  very  wide  rectangular  beam. 

(2)  Slab  considered  a  series  of  beams,  side  by  side,  each  beam 

having  one  reinforcing  rod  and  a  width  equal  to  the 
distance  on  centers  of  the  rods. 

•  (3)  Slab  considered  a  series  of  beams,  side  by  side,  each  beam 
having  a  unit-width  and  a  unit-area  of  reinforcement. 

In  the  following  table  the  values  of  K  and  of  the  other  constants  are  given, 
for  cinder  concrete.  This  table  should  be  used  only  for  slabs  between  floor 
beams,  as  cinder  concrete,  while  possessing  excellent  fire-resisting  properties,' 
is  weak  when  compared  with  the  stone  and  gravel  mixtures. 

XL. 

Constants  for  Reinforced  Cinder  Concrete  Slabs.    Ratio  of 

MoDULusEs,  35. 

For  r  =      =  35 


V 

X 

K 

C 

S 

K 

C 

S 

,0005 

.170 

7.5 

94 

16000 

7.5 

94 

16000 

,0010 

.232 

14.8 

138 

14.8 

138 

16000 

.0015 

.276 

21.8 

174 

18.8 

150 

13800 

.0020 

.311 

28.7 

206 

20.9 

11633 

,0025 

.340 

33.9 

225 

15300 

22.6 

10200 

.0030 

.365 

36.1 

13688 

24.0 

£125 

.0035 

.387 

37.9 

12439 

25.3 

8293 

.0040 

.407 

39.6 

11447 

26.4 

7631 

.0045 

.425 

41.0 

10625 

27,4 

7083 

.0050 

.442 

42.4 

9945 

28.3 

6630 

,0055 

.457 

43.6 

9348 

29.1 

6232 

.0060 

.471 

44.7 

8831 

29.8 

5888 

.0065 

.484 

45.7 

8377 

30.4 

5585 

,0070 

.497 

46.7 

7988 

31.1 

5325 

,0075 

.508 

47.5 

7620 

31.6 

5080 

,0080 

.519 

48.3 

7298 

32.2 

4866 

.0085 

.529 

49.0 

7001 

32.7 

4668 

-0090 

.539 

49.7 

6738 

33.2 

4492 

-0095 

.548 

50.4 

6489 

33.6 

4326 

-0100 

.557 

51.0 

6266 

34.0 

4178 

.0105 

.5&5 

51.6 

6054 

34.4 

4036 

.0110 

.573 

52.1 

5860 

34.8 

3907 

.0115 

.581 

52.7 

5684 

35.1 

3789 

.0120 

.588 

53.3 

5513 

35.5 

3675 

.0125 

.595 

53.7 

5355 

35.8 

3570  • 

.0130 

.602 

54.1 

5210 
5067 

36.1 

3473 

.0135 

.608 

54.5 

36.4 

3378 

,0140 

.615 

55.0 

4942 

36.7 

3295 

,0145 

.621 

55.4 

4818 

36.9 

3212 

,0150 

.626 

5.5.7 

4695 

37.1 

3130 

.0155 

.632 

56.1 

4587 

37.4 

3058 

.0160 

.637 

56.4 

4479 

37.6 

2986 

,0165 

.643 

56.8 

4384 

37.9 

2923 

,0170  - 

.648 

57.2 

4288 

38.1 

2859 

.0175 

.652 

57.4 

4191 

38.3 

2794 

,0180 

.657 

57.7 

4106 

38.5 

2738 

.0185 

.663 

58.1 

4026 

38.7 

ik 

2684 

.0190 

.666 

58.3 

3943 

38.9 

2629 

.0195 

.671 

58.6 

3871 

39.1 

ii 

2581 

.0200 

.675 

58.9 

3797 

39.2 

2531 

THEORY  AND  DESIGN. 


^S7 


539.  CONVENIENT  CHECK-FORMULAS  FOR  REIN- 
FORCED CONCRETE  RECTANGULAR  BEAM  CONSTRUC- 
TION.— Formulas  may  be  used  to  test  reinforced  concrete  beam 
calculations  and  construction. 

When  it  is  desired  to  find  the  safe  loading  for  a  given  beam 
the  following  forrnulas  may  be  used: 

M=pSbd2  (15) 
3f=^^(l-^)  (16) 

The  assumed  working  stresses  5^  and  C  are  substituted  in  these 
formulas,  and  if  the  resulting  values  for  M  are  unequal  the  smaller 
of  the  two  values  is  taken  for  the  proper  value  of  the  maximum 
bending  moment.  Resulting  inequality  of  values  for  M  indicates 
a  non-economical  proportion  or  arrangement  of  the  two  materials 
employed  and  a  failure  to  obtain  the  full  resistance  of  one  or  the 
other. 

When  it  is  desired  to  investigate  a  given  beam,  that  is,  to  find 
the  stresses  6^  and  C,  for  a  given  loading,  the  following  forms  of 
the  same  formulas  may  be  used: 

^  (17) 


vhd-  (i--f-) 

2M 


Z)d2  (1 


(18) 


In  formulas  (15)  and  (16)  x  is  found  from  the  tables  given, 
•and  in  formulas  (17)  and  (18)  it  is  determined  by  formula  (13). 

In  formula  (17)  the  denominator  of  the  second  member  of  the 
equation  is  a  transformed  expression  for  the  product  of  the  area 
of  the  cross-section  of  the  reinforcement  by  the  distance  of  its 
center  of  gravity  from  the  center  of  compression  of  the  concrete ; 
and  in  formula  (18)  the  denominator  of  the  second  member  of  the 
equation  is  an  expression  for  the  product  of  the  area  of  the  cross- 
section  of  the  concrete  in  compression  by  the  same  distance. 

540.  GENERAL  PRINCIPLES  OF  REINFORCED  CON- 
CRETE T-BEAM  DESIGN.— Fig.  501  is  a  cross-section  of  a 
reinforced  concrete  T-beam  formed  by  using' a  portion  of  the 


658 


BUILDING  CONSTRUCTION. 


(Ch.  X> 


floor  slabs  and  a  rectangular  beam  together  as  one  beam  of  T-shape. 
The  neutral  axis  of  the  cross-section  is  shown  and  also  the  rein- 
forcing rods  near  the  lower  surface  of  the  stem  or  web  part. 
y  —  the  width  of  the  slab  part  taken. 

—  the  depth  of  the  slab. 
h  =  the  width  of  the  stem. 

X  and  xd,  and  the  other  terms  of  the  formulas  have  the  same 
meanings  as  in  Articles  536  and  537,  in  the  formulas  for  rectangular 
beams. 

Floor  slabs  are  commonly  used  in  connection  with  beams  and 
girders,  and  an  economical  design  results  when  they  are  casf  as 


units  and  considered  together,  as  the  slabs  add  much  to  the  strength 
of  the  beams  or  girders. 

Practice  and  building  regulations  differ  in  regard  to  the  width 
of  the  slab  to  be  considered  as  part  of  the  beam.  The  New  York 
building  laws  give  "ten  times  the  width  of  the  beam  or  girder," 
or  the  stem  of  the  T-beam.  Other  regulations  give  as  a  maximum 
width  for  the  flange  one-third  the  span  of  the  beam. 

It  is  generally  convenient  to  first  determine  the  necessary  thick- 
ness of  the  floor  slabs  required  for  any  particular  case  of  beam 
spacing,  taking  this  thickness  for  that  of  the  T-beams. 

When  such  T-beams  frame  into  reinforced  concrete  girders, 
these  girders  also  may  be  designed  as  T-girders,  with  slab  flanges 
of  the  same  thickness  as  is  used  for  the  beam  slabs ;  and  the  same 
slab,  or  as  much  of  it  as  is  required,  may  be  used  for  both  beam 
and  girder  when  they  come  together.  Both  have  compressive 
stresses  and  some  authorities  claim  that  they  assist  each  other;  while 


.4 


Fig.   501,     Cross-section   Reinforced  Concrete  T-beam. 


THEORY  AND  DESIGN, 


659 


others  endeavor  to  avoid  '"an  integration  of  compressive  stresses 
due  to  simultaneous  action  as  floor  slab  and  girder  flange."* 

541.  FORMULAS  FOR  REINFORCED  CONCRETE 
T-BEAMS. — For  these  beams  there  may  be  considered  any  one 
of  three  positions  of  the  neutral  axis : 

(1)  The  neutral  axis  of  the  cross-section  may  be  below  the 

flange. 

(2)  The  neutral  axis  may  be  in  the  plane  of  the  under  surface 

of  the  flange. 

(3)  The  neutral  axis  may  be  above  the  under  surface  of  the 

flange. 
In  the  first  case 


(19) 


M=-^  {d  -  -—)  (20) 

To  simplify  the  formulas,  the  center  of  compression  in  the  con- 
crete is  taken  at  the  middle  of  the  thickness  of  the  flange,  and  the 
small  proportion  of  concrete  in  compression  below  the  flange  and 
above  the  neutral  axis  is  neglected. 

The  position  of  the  neutral  axis  may  be  found  by  the  formula 

2d  (hdijr  +  b'h')  ' 

The  most  economical  percentage  of  reinforcement  may  be  found 
by  the  formula 

C  /)'  h' 


2Shd 


(22) 


In  this  formula  the  area  bd,  only,  of  the  concrete  is  taken  and 
the  remainder  of  the  concrete  cross-section  area  negltcted. 

In  the  second  case  the  formulas  for  the  values  of  M  and  of  p  are 
the  same  as  for  the  first  case,  and      becomes  xd. 

In  the  third  case  the  treatment  is  the  same  as  in  the  second  case 
because  the  flange  concrete  below  the  neutral  axis  is  neglected. 
Thus,  in  this  case  also,  h'  becomes  xd. 

542.  WORKING  UNIT-STRESSES  IN  REINFORCED 
CONCRETE  DESIGN. — Some  working  stresses  for  mass  con- 
crete and  also  for  reinforced  concrete  construction  have  been  given 
in  Article  503.  The  allowable  working  stresses  for  concrete  and 
steel  in  several  cities  is  given  in  the  following  table : 

*  "Building  Laws  and  Ordinances,"  Philadelphia. 


'66o  BUILDING  CONSTRUCTION.  (Ch.  X) 


TABLE  XLI. 

Working  Unit-stresses  for  Reinforced  Concrete  Design. 


tn  0) 

O  (C 

o  o 

er  Str< 
Concn 
Inch 

Tensi 
Concr* 
Inch 

o  (s 

as 

3  in  St< 
Incli 

tress 
Squa 

xtreme  Fib 
in  (yomp.  in 
Per  Square 

c 

i  a  g  0  n  a  I 
Stress  in 
Per  Square 

irect  Comp 
Crete  Per 
Inch 

dhesion  of 
Concrete  P( 
Inch 

CO  a 

hearing  S 
Steel  Per 
Inch 

atio  of  Mo 
Steel  to  M( 
Concrete  (r 

O 

< 

rsi 

500 

50 

350 

50 

16000 

10000 

13 

500 

75 

350 

75}^ 

"^Elastic 
Limit 

10000 

12 

Philadelphia  

600 

75 

5^K)  Col's. 

50 

16000 

12 

500 

50 

a50 

50 

18 

15  in 

500 

60 

416  Mx 
347  Mn 

Beams  and 
Slabs  and 

10  in  Col's 

500 

50 

a50 

50 

16000 

10000 

15 

Buffalo  

500 

50 

350 

50 

160UO 

10000 

12 

San  Francisco  

500 

75 

450 

75 

i^Elastic 
Limit 

10000 

15 

National  Board  of 

Fire  Underwriters 

500 

50 

350 

50 

18 

The  stresses  are  for  "medium  steel."  The  working  stresses  in 
the  steel  should  be  a  fixed  proportion  of  either  the  yield  point  or 
of  the  elastic  limit.  The  working  unit  tensile  stress  for  "high 
carbon  steel"  is  ordinarily  taken  as  20,000  pounds  per  square  inch. 

The  values  of  r  = ,  C  and  6^,  given  in  the  table  above,  are 
used  in  determining  the  value  of  K  in  the  formula  (11)  of  Article 
536,  when  the  value  of  K  is  not  taken  dirertly  from  Tables 
XXXVIII  and  XXXIX. 

543.  MODULUSES  OF  ELASTICITY  OF  STEEL  AND 
CONCRETE  IN  REINFORCED  CONCRETE  DESIGN.— In 
order  to  know  the  value  of  the  r  =  -^  of  the  formulas  and 
tables,  it  is  necessary  to  know  the  values  of  E^,  the  modulus  of 
elasticity  of  steel  and  of  E^,  the  modulus  of  elasticity  of  concrete. 

The  average  of  the  former  is,  for  practical  work,  generally 
accepted  as  about  30,000,000  pounds  per  square  inch,  and  of  the 
latter  as  about  2,500,000  pounds  per  square  inch. 

These  values,  of  course,  are  averages,  and  there  are  great  varia- 
tions, especially  for  concrete,  the  value  of  E^  varying  with  many 
conditions,  such  as  the  character  of  materials,  the  manner  of  mixing 


THEORY  AND  DESIGN. 


66r 


and  placing,  the  age  of  the  concrete,  the  richness  of  the  mixture, 
the  amount  of  load  on  the  concrete,  etc. 

544.  BENDING  MOMENTS  IN  REINFORCED  CON- 
CRETE BEAM  DESIGN.— The  correct  values  of  M,  the  maxi- 
mum bending  moment  of  the  external  forces  acting  on  a  reinforced 
concrete  beam  or  slab,  have  to  be  found.    The  values  are  deter- 


c 

 V  ^ 

\  1 

Fig.  502.     Bending  Moment  Diagram.     Uniformly  Distributed  Load. 


mined  by  theoretical  considerations  of  the  laws  of  flexure  or  fixed 
by  the  requirements  of  building  laws. 

Figs.  502  and  503  are  simple  diagrams  illustrating  in  a  very 
general  way  the  average  usual  disposition  of  reinforcements  in. 
beams,  with  reference  to  the  kind  of  loading,  the  supports,  the 
positions  of  the  positive  and  negative  bending  moments,  etc. 

In  continuous  beams  there  are  positive  bending  moments  between 
the  supports  and  negative  bending  moments  over  the  supports. 
Reinforcements  in  the  upper  part  of  a  continuous  beam  should  be 
provided  for  the  latter.     In  simple  beams  the  bending  moment 


c 

Fig.   503.     Bending   Moment   Diagram.     Concentrated  or  Unsymmetrical  Load. 

decreases  toward  the  supports.  Accordingly,  the  steel  reinforcing 
rods  should  be  disposed  in  sets  or  pairs  to  resist  the  tensional 
stresses,  some  of  them  running  up  toward  the  upper  parts  of  the 
beam  as  they  approach  the  supports  and  there  carried  across  if  the 
beams  are  continuous. 

Fig.  502  shows  the  position  of  the  maximum  positive  bending 
moment  and  the  general  arrangement  of  reinforcement  for  a  uni- 
formly distributed  or  symmetrical  load,  and  Fig.  503  for  a  con- 
centrated or  unsymmetrical  load. 

The  calculations  involved  in  designing  continuous  beams  are 


662 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


relatively  complicated,  and  reinforced  concrete  beams  are  usually 
treated  as  ''simple  beams,"  that  is,  as  beams  supported  at  the  ends 
and  not  continuous.  The  difference  in  the  results  of  the  calcula- 
tions is  on  the  side  of  safety.  The  building  laws  of  the  following, 
among  other  large  cities,  require  that  beams  and  girders  shall  be 
considered  as  simply  resting  on  two  supports :  New  York,  Chicago, 
Philadelphia,  Cleveland,  San  Francisco,  Buffalo  and  St.  Louis. 

545.  BENDING  MOMENTS  IN  REINFORCED  CON- 
CRETE SLAB  DESIGN. — Floor  slabs  are  usually  carried  continu- 
ously across  supports  over  wide  areas,  and  bending  moments  due 
to  uniformly  distributed  loads  are  considered  to  be  less  in  magni- 
tude than  in  beams  resting  on  two  supports. 

The  following  are  the  Philadelphia  building  laws  for  reinforced 
concrete  floor  slabs : 

''Floor  slabs,  when  constructed  continuously,  and  when  provided 
with  reinforcement  at  top  of  a  slab  over  the  supports,  may  be  treated 
as  continuous  beams,  the  bending  moment  for  uniformly  distributed 
loads  being  taken  at  not  less  than  In  case  of  square  floor 

slabs  which  are  reinforced  in  both  directions  and  supported  on  all 
sides,  the  bending  moment  may  be  taken  at  ~,  provided  that 
in  floor  slabs  in  juxtaposition  to  the  walls  of  the  building  the 
bending  moment  shall  be  considered  as  when  reinforced  in 

one  direction ;  and  if  the  floor  slabs  are  square  and  reinforced  in 
both  directions,  the  bending^  moment  shall  be  taken  ?s  —.^^ 

In  the  above,  W  is  the  total  load  on  a  slab  in  pounds,  and  /  the 
span  in  inches,  the  resulting  bending  moment  being  in  inch-pounds. 

The  following  is  a  formula  proposed  by  Professor  C.  Bach  for 
the  bending  moment  of  slabs  supported  on  four  sides  and  reinforced 
in  both  directions : 

M-JL«'^p  (23, 

M  =  maximum  bending  moment  in  inch-pounds  for  a  uniformly 

distributed  load. 
a  =  the  length  of  the  slab  in  inches. 
b  =  the  width  of  the  slab  in  inches. 
p  =  the  load  on  the  slab  per  square  inch. 

546.  AMOUNT  OF  REINFORCEMENT  AND  ITS  DIS- 
POSITION IN  CONCRETE  BEAMS.— Figs.  502  and  503  show 
some  general  arrangements  and  numbers  of  rods.    At  the  beam 


THEORY  AND  DESIGN. 


663 


sections  of  maximum  bending  moment  full  sectional  areas  of  rein- 
forcement must  be  provided,  and  throughout  the  beam  these  areas 
must  be  sufficient  to  resist  the  tensional  stresses  below  the  neutral 
axis.  The  turning  up  of  some  of  the  rods  must  .be  done  at  the 
proper  places,  depending  upon  the  character  of  the  loading. 

An  even  number  of  rods  is  better  adapted  to  a  symmetrical 
arrangement  in  cross-section  and  longitudinal  section,  in  regard  to 
the  grouping  at  and  near  the  point  of  maximum  bending  moment 
and  to  the  turning  up  toward  the  supports.  Too  great  a  number 
of  rods  is  undesirable,  but  a  larger  number  of  smaller  rods  is 
preferable  to  a  smaller  number  of  larger  rods,  as  the  areas  of 
contact  for  cylindrical  rods  decrease  as  the  diameters  of  their  cir- 
cular cross-section,  while  the  volumes  of  the  rods  decrease  as  the 
squares  of  the  diameters. 

'  Whatever  the  arrangement,  the  rods  must  be  satisfactorily 
incased  in  the  concrete.  Partly,  if  not  entirely,  on  account  of  an 
insufficiency  of  concrete  between  and  around  the  rods,  the  con- 
crete sometimes  splits  off  along  the  line  of  reinforcement  at  the 
under  side  of  beams  during  tests.  This  result  is  avoided  by  spac- 
ing the  rods  in  the  cross-sections  so  that  the  resistance  of  the 
concrete  to  shear  at  the  level  of  the  rods  is  at  least  equal  to  the 
adhesion  of  the  concrete  to  the  steel. 

If  the  safe  values  for  adhesion  and  shear  are  taken  about  equal, 
the  rods  should  be  spaced  2^  diameters  on  centers  and  2  diameters 
from  the  sides  of  the  beams.  Authorities  do  not  agree  yet  on 
this  point,  some,*  for  example,  naming  inches  as  a  minimum 
and  othersf  naming        inches  as  a  sufficient  maximum  distance. 

The  percentage  of  reinforcement  for  rectangular  and  T-beams 
is  found  as  explained  in  Articles  536  and  541  by  the  formulas  (12) 
and  (22).  The  amount  may  vary  from  one-fourth  of  one  per  cent 
to  one  and  one-half  per  cent  of  the  concrete  area.  A  usual  average 
is  about  seven-tenths  of  one  per  cent. 

After  deciding  upon  the  number  of  rods  required,  the  size  of 
each  one  can  be  found  and  the  rods  selected  "  from  tables,  manu- 
facturers' catalogues,  etc. 

547.  BREADTH  OF  REINFORCED  CONCRETE  BEAMS. 
— In  Article  537,  in  using  the  formula  to  determine  the  size  of  rec- 

*  "Concrete,  Plain  and  Reinforced."     Taylor  &  Thompson. 

t  Brooklyn,   N.   Y.,  Regylations  for  Reinforced  Concrete  Construction. 


664 


BUILDING  CONSTRUCTION. 


(Cii.  X) 


tangular  beams,  the  breadth  of  the  beam  is^assumed.  The  breadth 
may  be  said  to  depend  generally  upon  the  necessary  reinforcement, 
and  upon  the  safe  ratio  of  the  least  side-dimension  of  cross-section 
to  the  length  of  the  beam,  considered  as  a  column  in  compression 
above  the  neutral  axis.  In  regard  to  the  amount  of  reinforcement,, 
the  necessary  width  equals  the  sum  of  the  diameters  of  the  tension 
rods,  the  spaces  between  them  and  the  amount  of  concrete  outside 
them  necessary  to  resist  shear  and  to  protect  the  metal ;  and  when 
stirrups  are  omitted  the  width  of  concrete  must  be  sufficient  to  resist 
the  horizontal  shear,  a  width  which  should  be  at  least  equal  to  the 
sum  of  the  perimeters  of  the  cross-sections  of  the  tensional  rein- 
forcing rods. 

The  breadth  is  often  assumed  equal  to  from  1/24  to  1/20  of 

the  span.  The  best-shaped  beam  is  usually  one  in  which  the 
breadth  lies  between  ^  and  34  of  the  depth. 

The  thickness  of  the  concrete  below  the  rods  is  determined  by 
the  requirements  of  fire-protection  and  corrosion-resistance.  The 
thickness  varies  from  i  to  2  inches,  according  to  conditions. 

548.  DIAGONAL  TENSION  IN  REINFORCED  CON- 
CRETE BEAM  DESIGN.— In  Article  503  the  average  safe  unit- 
value  for  the  'Vertical  shear"  for  concrete  is  given,  and  in  Article 
531  this  unit  stress  is  defined.  What  is  often  termed  ''shear"  in  a 
reinforced  concrete  beam  is  really  diagonal  tension.  There  is  a  ten- 
dency to  shear  horizontally  at  the  neutral  surface  of  a  beam,  and 
this  tendency  diminishes  toward  the  top  and  bottom  of  a  beam. 
The  diagonal  tension  in  this  case  should  not  exceed  from  50  to  75 
pounds  per  square  inch,  and  is  taken  in  building  laws  at  from  50 
to  75  pounds  per  square  inch.  It  will  be  noticed  that  this  value 
is  just  about  the  allowable  adhesive  and  tensional  stress  of  the 
concrete. 

To  resist  these  diagonal  tension  stresses  in  the  concrete,  metal 
"stirrups"  are  provided  and  fastened  in  some  way  to  the  lower 
rods.  The  exact  amount  and  position  of  such  stirrups  for  any 
particular  case  of  reinforcement  are  not  definitely  agreed  upon 
by  different  authorities,  some  claiming  that  they  should  be  vertical, 
others  that  they  should  be  inclined.  The  stirrups  are  generally 
firmly  attached  to  the  tensional  reinforcement,  although  some  claim 
that  this  is  not  necessary.  Dififerent  kinds  of  stirrups  are  shown, 
in  the  dififerent  types  of  reinforcements  and  construction. 


THEORY  AKD  DESIGN. 


665 


The  size  and  spacing  of  stirrups  may  be  determined  by  formulas 
given  in  hand-books  on  the  subject.* 

549.  COMPRESSION  RODS  IN  REINFORCED  CON- 
CRETE BEAMS. — The  use  of  steel  in  compression  in  concrete 
beams  is  not  geaerally  recommended,  since  it  is  more  economical 
to  carry  compressive  stresses  by  the  concrete  than  by  the  steel. 
Limitations  as  to  size,  however,  and  the  occasional  desirability  of 
providing  additional  compressive  strength  where  there  is  not  suffi- 
cient concrete  above  the  neutral  axis  to  resist  the  total  compression, 
leads  to  the  introduction  of  a  double  reinforcement  in  the  shape 
of  rods  in  the  upper  portion  of  the  beams. 

Steel  reinforcement  in  the  compressive  side  has  little  effect  in 
beams  that  would  otherwise  fail  in  tension  shear,  the  only  gain 
being  that  due  to  an  increased  distance  between  centers  of  resultant 
tensile  and  compressive  forces.  Tests  made  on  doubly  reinforced 
beams  show  that  the  steel  in  compression  takes  its  share  of  stress,  ^ 
and  that  the  compressive  side  of  the  beam  is  strengthened  in  accord- 
ance with  the  usual  theory.  Steel  with  a  fairly  high  elastic  limit 
should  be  used  in  order  to  obtain  its  full  benefit  up  to  the  point 
of  rupture. 

The  steel  should  be  placed  as  high  as  possible.  The  usual  rule 
is  to  limit  the  allowable  unit-compression  in  the  steel  to  th^  actual 
compression  in  the  concrete  at  that  point  multiplied  by  the  ratio  of 
the  modulus  of  elasticity  of  the  steel  to  that  of  the  concrete,  as  in 
the  case  of  columns  with  vertical  reinforcement. 

550.  ADHESION  OF  THE  CONCRETE  TO  THE  REIN- 
FORCEMENT.— In  a  reinforced  concrete  beam  in  a  state  of 
flexure  under  a  load  there  is  a  tendency  for  the  concrete  to  shear 
horizontally  along  the  reinforcement.  This  is  resisted  in  part  by 
the  adhesion  between  the  steel  and  the  concrete.  With  plain  round 
or  square  rods  the  adhesion  between  the  two  materials  furnishes 
the  only  bond,  but  various  commercial  types  of  bars  are  in  use, 
provided  with  projections  or  indentations  of  different  shapes  to 
prevent  slipping.  Either  a  so-called  "mechanical  bond"  is  formed 
or  the  reinforcements  are  anchored  at  the  ends. 

Many  tests  have  been  made  to  determine  the  force  necessary  to 
pull  "bars  of  different  cross-sections  from  the  concrete,  and  to 
determine  the  adhesion  between  the  materials. 


*  See  the  "Architect's  and  Builder's  Pocket-Book,"  Frank  E.  Kidder,  Chapter  XXIV, 
and  Engineering  News,  April  16,  1903,  p.  348. 


666 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


The  results  of  some  valuable  pulling-out  tests  made  by  Professor 
Edgar  Marburg,  of  the  University  of  Pennsylvania,  are  given  in 
the  following  table.*  In  these  tests  the  rods  were  centrally 
imbedded  in  6-inch  by  6-inch  concrete  prisms  12  inches  long  and 
were  tested  after  thirty  days. 

The  plain  rods  generally  pulled  out,  but  in  most  of  the  cases  of 
the  other  rods  failure  was  due  to  the  breaking  of  the  rods  or  to 
the  cracking  of  the  concrete. 


TABLE  XLII. 
Pulling-out  Tests. for  Different  Reinforcing  Rods. 


Kind  of  Rod 

Total  Load, 
Pounds 

Load  Per 
Linear  Inch 
of  Rod, 
Pounds 

Remarks 

13660 

1138 

Elastic  limit  passed.   Concrete  cracked 

12830 

1069 

Elastic  limit  passed.   Concrete  cracked 

9980 

833 

Concrete  cracked 

6280 

524 

Rod  pulled  out 

6190 

516 

Rod  pulled  out 

5650 

471 

Rod  pulled  out 

.  10420 

868 

Rod  broke 

Thacher  - 

8890 

741 

Concrete  cracked 

9970 

831 

iiod  broke 

22890 

1891 

Concrete  cracked 

Ransome  - 

16680 

1390 

Concrete  c l  acked 

19290 

•  1608 

Rod  pulled  out 

In  a  beam  conditions  are  more  favorable  than  in  tests  conducted 
by  either  a  method  of  pulling  out  or  one  of  pushing  out,  as  in  a 
beam  both  the  steel  and  the  concrete  are  elongated  and  the  stress 
has  thus  a  tendency  to  distribute  itself  more  equally. 

From  the  various  data  of  tests  the  ultimate  adhesive  strength 
for  ordinary  round  or  square  rods  may  be  taken  at  from  250  to 
400  pounds  per  square  inch,  and  the  working  strength  at  from 
50  to  75  pounds  per  square  inch.  A  round  bar  needs  to  be  imbedded 
a  length  of  about  60  diameters  to  develop  its  full  strength.  In  case 
the  bars  are  of  large  diameter  and  in  any  case  in  which  such  a 
length  is  difficult  to  secure,  deformed  or  anchored  bars  are  of 
especial  value. 

For  deformed  bars  the  safe  working  strength  may  be  taken  at 
about  ICQ  pounds  per  square  inch,  the  required  length  of  the  im- 
bedding being  about  37  diameters. 


*  Proc.  Amer.  Soc.  of  Testing  Materials,  1904. 


THEORY  AND  DESIGN. 


667 


551.  REINFORCED  CONCRETE  COLUMN  DESIGN.— 
Reinforced  concrete  columns  are  of  two  general  types:  (i)  Rein- 
forcement all  vertical  and  near  the  outer  surface  and  tied  at  inter- 
vals principally  to  keep  it  in  place;  (2)  reinforcement  composed  of 
circular  or  spiral  wrappings  or  hoops  of  wire  or  steel  bands  or 
rods,  with  simply  enough  vertical  rods  to  tie  the  wrappings  to. 
The  ultimate  strength  is  raised  by  either  of  these  types  of  reinforce- 
ment, but  conclusive  results  have  not  been  reached  as  to  the  true 
relative  effect  of  different  types  and  amounts  of  reinforcement. 

There  are  two  other  types,  which  are  concrete-protected  columns 
rather  than  reinforced  concrete  columns:  (3)  Reinforcement  com- 
posed of  sufficient  steel  to  carry  the  load,  with  sufficient  concrete 
to  protect  it  and  increase  the  stiffness  and  factor  of  safety;  (4) 
reinforcement  composed  of  sufficient  steel  to  act  as  a  column  strong 
enough  to  support  all  the  dead  loads,  with  sufficient  concrete  to 
support  all  the  live  loads. 

The  cost  of  columns  of  reinforced  concrete  is  generally  less  than 
that  of  columns  of  steel  or  iron. 

They  occupy  more  space  than  columns  of  other  materials  usually 
employed.  The  following  are  the  cross-section  sizes  of  six  columns 
of  different  materials,  supporting  a  safe  load  of  50  tons,  the  length 
being  18  feet.* 


Steel  (two  6-inch  latticed  channels)   6  by   8  inches. 

Cast-iron  (hollow  and  round)   8  inches  in  diameter. 

Yellow  pine    11  by  11  inches. 

Oak    12  by  12  inches. 

White  pine  or  spruce   13  by  13  inches. 

Reinforced  concrete    18  by  18  inches. 


Regarding  the  length  of  reinforced  concrete  columns,  building 
ordinances  generally  require  that  the  ratio  of  length  to  least  lateral 
dimension  shall  not  be  greater  than  from  12  to  16,  usually  12. 
Flexure  might  be  caused  by  a  heavy  load,  and  if  the  column  were 
long  enough  the  reinforcing  rods  might  bend  sufficiently  to  cause 
the  concrete  to  fail. 

The  following  are  the  limiting  ratios  of  length  to  least  lateral 
dimension  given  by  the  building  laws  of  some  of  the  largest  cities : 


*  See   "Reinforced  Concrete,"   by   Ernest  McCullough. 


668  BUILDING  CONSTRUCTION.  (Ch.  X) 

New  York  (Manhattan)   12 

New  York  (Brooklyn)   13 

Chicago    12 

Philadelphia   15 

St.  Louis    12 

Buffalo   16 

San  Francisco    15 

National  Board  of  Fire  Underwriters   12 


It  is  rarely  necessary  to  calculate  these  columns  as  long  columns, 
as  in  ordinary  construction  the  ratio  of  length  to  least  width  will 
seldom  exceed  from  12  to  15.  Results  of  tests  also  show  Httle  or 
no  difference  in  strength  for  ratios  up  to  20  or  25. 

552.  STRENGTH  OF  LONGITUDINALLY  REINFORCED 
CONCRETE  COLUMNS.— Some  authorities  determine  the 
strength  of  concrete  columns  with  longitudinal  reinforcements  by 
assuming  that  the  reinforcement  carries  a  load  per  square  inch 
equal  to  the  product  of  the  working  load  per  square  inch  in  the 
concrete  by  the  ratio  of  the  moduluses  of  elasticity  of  the  two 
materials.  Thus,  for  example,  if  a  load  of  350  pounds  per  square 
inch  is  used  for  the  concrete,  and  if  15  is  taken  as  the  ratio  of 
the  moduluses  of  elasticity  of  the  steel  and  the  concrete, 
350  X  15  =  5^250  pounds  per  square  inch  is  the  allowable  unit  load 
on  the  steel. 

Again,  some  authorities  figure  a  higher  unit  stress  on  the  con- 
crete, allowing  no  load  on  the  steel,  assuming  that  its  function  is 
merely  to  resist  flexure  and  therefore  providing  a  percentage  of 
steel  area  sufficient  for  that  purpose  only. 

The  relative  intensities  of  compressive  stress  in  the  two  materials 
will  be  as  their  moduluses  of  elasticity,  as  long  as  the  steel  and 
concrete  adhere. 

The  following*  are  simple  and  reliable  formulas  for  determining 
the  safe  strength  of  the  column,  the  stress  in  the  steel  and  the 
percentage  of  steel  required  for  concrete  columns  with  longitudinal 
reinforcement : 

*  This  is  the  treatment  of  the  subject  given  by  Professors  Turneaure  and  Maurer  in 
"Principles  of  Reinforced  Concrete  Construction,"  to  which  the  reader  is  referred  for 
further  detailed  discussions  of  the  theoretical  strength  of  concrete  columns  and  also 
discussions  of  numerous  recent  tests. 


THEORY  AND  DESIGN. 


669 


Let  A  —  xhQ  total  cross-section  of  the  column; 
"    Ac  —  iht  cross-section  of  the  concrete; 
"    A%  —  t\\t  cross-section  of  the  steel; 
"     p  —  the  ratio  of  steel  area  to  total  area  =  As/ A ; 
"     /c  =  the  unit  compressive  stress  in  the  concrete; 
"     /s  —  the  unit  compressive  stress  in  the  steel ; 

"  n  =  E^/E^  —  the  ratio  of  moduliises  of  steel  and  concrete  at  the  given 
stress  f,- ; 

Let  £c  =  the  modulus  of  elasticity  of  the  concrete; 
"    Es  =  the  modulus  of  elasticity  of  the  steel ; 
'    "     P  =3  the  total  strength  of  a  plain,  non-reinforced  concrete  column 
for  the  stress  of  /c ; 
"     P'  —  the  total  r,trength  of  a  reinforced  concrete  column  for  the  stress  /"e. 
Then  P  =  fcA  (24) 
and  P'  =  /c  Ac  -f  /s  As  =  fc  (A  —  pA)  -\-  fdipA 
whence  P'r=/c/i  [1 -f      —  (25) 
and  dividing  equation  (25)  by  equation  (24), 

^  =  I  +  (/;  —  i)  p.  (26) 

The  relative  increase  in  strength  due  to  the  reinforcement  is 
given  by 

The  ultimate  strength  of  the  column  may  be  afifected  by  a  low 
elastic  limit  in  the  steel,  and  in  this  case 

P^=fc  Ac+fsAs  (28) 

in  which  equation  /s  is  taken  a§  the  elastic  limit  strength  of  the 
Steel. 

If  it  is  required  to  determine  the  relative  strength  of  a  reinforced 
concrete  column  and  one  which  is  without  reinforcement,  for  a 
given  percentage  of  steel,  equation  (26)  may  be  used.  For  example, 
if  /)  =  1.5  per  cent  and  n  =  12,  then  _^  =  i  ^  0.165  =  i-i^S-  In 
this  particular  case  the  strength  is  increased  16^  per  cent  by  a 
reinforcement  of  per  cent,  and,  in  general,  for  any  given 

amount  of  reinforcement  the  relative  increase  in  strength  varies 
directly  as  n.  The  above  relations  show  also  that  the  economy  of 
steel  reinforcement  depends  upon  the  allowable  working  stresses  in 
the  concrete,  as      =  nfc. 

The  following  table*  is  useful  m  connection  with  the  subject 
of  the  longitudinal  reinforcement  of  concrete  columns : 


*  From  "Principles  of  Reinforced  Concrete  Construction,"  Turneaure  and  Maurer. 


670 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


TABLE  XLIII. 
Longitudinal  Reinforcement  of  Columns. 


Pounds  Per 
Square  Inch 

Ratio  of 
Moduluses, 

n 

Pounds  Per 
Square  Inch 

Percentage  Increase 

in  Strength  for 
Each  1  Per  Cent  Re- 
inforceraent 

750000 

40 

12000 

39 

1000000 

30 

9n00 

29 

1500000 

20 

6000 

19 

2000000 

15 

4»00 

14 

1000000 

30 

12000 

29 

1500000 

20 

18000 

19 

2000000 

15 

6000 

14 

2500000 

12 

4800 

11 

1000000 

30 

15000 

29 

1500000 

20 

10000 

19 

2000000 

15 

7500 

14 

2500000 

12 

6000 

11 

1500000 

20 

15000 

19 

2000000 

15 

10000 

14 

250000!) 

12 

7200 

11 

3000000 

10 

6000 

9 

2000000 

15 

12000 

14 

2500000 

12 

9600 

11 

3000000 

10 

8000 

9 

3500000 

8.6 

6900 

7.6 

Pounds  Per 
Square  Inch 


300. 


400. 


600. 


600. 


800. 


In  this  table  the  first  column  gives  the  various  values  of  the 
working  compressive  stress  in  pounds  per  square  inch  in  the  con- 
crete; the  second  column  gives  the  various  values  of  the  moduluses 
of  elasticity  in  pounds  per  inch  for  the  concrete ;  the  third  column 
gives  the  various  ratios  of  the  moduluses  of  elasticity  of  steel  and 
concrete ;  the  fourth  column  gives  the  various  values  of  the  working 
stresses  in  pounds  per  square  inch  in  the  steel ;  and  the  fifth  column 
gives  the  percentage  increase  in  strength  for  each  one  per  cent  of 
steel. 

This  table  indicates  also  that  the  working  stresses  in  the  rein- 
forcement are  relatively  low  except  in  the  case  of  an  unusual  com- 
bination of  high  working  compressive  stresses  in  the  concrete  with 
a  low  modulus  of  elasticity  in  the  same  material.  This  combination 
is  uncommon,  because  high-grade  concrete  mixtures,  allowing  high 
working  compressive  stresses,  have  a  high  modulus  of  elasticity. 

553.  EXAMPLES  IN  REINFORCED  CONCRETE  COL^ 
UMN  DESIGN. — The  following  two  examples  will  illustrate  the 
general  method  of  designing  concrete  columns  with  longitudinal 
reinforcement : 

(i)  Example.  What  is  the  safe  strength  of-  a  column  14  inches 


THEORY  AND  DESIGN. 


671 


by  14  inches  in  cross-section  and  rcinforced  with  i  per  cent  of 
steel,  the  working  stress  of  the  concrete  being  taken  at  350  pounds 
per  square  inch  and  //  being  taken  at  12  ? 

Solution.  Using  equation  (25)  and  substituting,  there  results 

p'=350  X  U  X  14  X  (1  +  11  X  -j^)  =68,600  (1  -!-  0.11)  =76,146  pounds. 

The  strength  ,  of  the  concrete  column  without  reinforcement  is 
68,6oo  pounds,  and  the  relative  increase  in  strength  is  ii  per  cent. 
The  unit  compressive  stress  in  the  steel  is  /s  =:  nfc  =  12  X  35o  = 
4,200  pounds  per  square  inch. 

(2)  Example.  The  area  of  the  cross-section  of  a  column  is 
144  square  inches,  the  load  carried  70,000  pounds,  the  working  unit 
stress  for  the  concrete  400  pounds  per  square  inch  and  n  is  15. 
What  is  the  required  percentage  of  steel  reinforcement? 

Solution.  The  safe  strength  of  the  concrete- column  without  rein- 
forcement is  400  X  144  =  57,600  pounds.  Using  equation  (26)  and 
substituting,  there  results 

— 57  600=^  +  ^^^-1^^^-  ^^^^^ 
V  p=g-;:g —  1 14=1.54  per  cent. 

554.  AMOUNT  AND  DISPOSITION  OF  LONGITUDINAL 
REINFORCEMENT. — The  percentage  of  cross-section  of  longi- 
tudinal reinforcement  usually  varies  from  i  per  cent  to  2}4  per 
cent. 

As  in  the  case  of  beams,  care  should  be  taken  in  the  disposition  of 
the  steel  to  avoid  using  too  much  of  it  and  to  avoid  putting  the 
rods  too  close  together.  The  longitudinal  reinforcing  rods  should 
not  be  placed  nearer  than  2  inches  to  the  outside  surfaces  of  the 
column  because  of  the  necessary  concrete  fire-protection ;  on  the 
other  hand,  for  purposes  of  resistance  to  lateral  flexure,  the  rods 
should  be  placed  as  close  to  the  outside  surfaces  as  possible. 

In  order  to  resist  the  tendency  to  buckle  and  the  resulting  ten- 
dency of  the  concrete  to  crack  and  to  split  off,  horizontal  ties  are 
used  to  hokl  the  longitudinal  reinforcing  rods  in  position ;  but 
these  ties  should  be  so  placed  that  the  interior  spaces  are  as  full 
as  possible,  so  as  not  to  interfere  with  the  proper  placing  of  the 
concrete,  which  is  usually  poured  into  the  column  molds  at  their 
tops.  The  distance  apart  of  these  horizontal  ties  should  be  not 
greater  than  the  diameter  or  the  least  lateral  dimension  of  the 
column. 


672 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


555.  STRENGTH  OF  CONCRETE  COLUMNS  WITH 
WRAPPED  OR  HOOPED  REINFORCEMENTS.— In  a 
wrapped  or  hooped  concrete  column  the  resistance  to  rupture  by 
compression  is  increased  by  the  lateral  restraint  of  the  reinforce- 
ment, so  that  a  higher  unit  compressive  strength  is  developed.  The 
concrete  is  prevented  from  spreading  laterally. 

The  increase  in  strength  due  to  lateral  banding  depends  upon 
the  rigidity  of  the  bands,  which  in  turn  depends  upon  the  amount 
-of  steel,  the  closeness  of  its  spacing  and  its  elastic  limit. 

Several  investigators  have  deduced  theoretical  relations  between 
the  lateral  and  longitudinal  stresses,  and  developed  formulas  for 
use  in  the  design  of  these  columns ;  and  results  of  tests  appear  to 
•accord  in  a  general  way  with  these  theoretical  relations. 

A  comparison  of  theoretical  formulas  and  results  of  tests  lead 
to  the  following  conclusions  :*  "It  would  appear  that  within  the 
limit  of  elasticity  the  hooped  reinforcement  is  much  less  efifective 
than  longitudinal  reinforcement ;  in  fact  it  would  seem  that  very 
little  stress  can  be  developed  in  the  steel  under  elastic  conditions 
as  here  assumed.  Such  reinforcement  may,  however,  be  quite 
efifective  in  increasing  the  iiltiriiate  strength  of  a  column.  Hooped 
columns  have  a  relatively  large  deformation,  reaching  at  an  early 
stage  a  deformation  equal  to  the  maximum  for  plain  concrete. 
Under  further  loading  the  concrete  is  prevented  by  the  banding  from 
actual  failure,  but  continues  to  compress  and  to  expand  laterally, 
increasing  the  tension  in  the  bands,  the  elasticity  of  the  bands  ren- 
dering the  columm  in  large  degree  still  elastic.  Final  failure  occurs 
upon  the  breakage  of  the  bands  or  with  their  excessive  stretching. 
Banded  columns  thus  exhibit  a  toughness  or  ductility  much  greater 
than  other  forms,  but  without  a  corresponding  increase  in  stiffness 
under  lower  loads.  Ultimate  failure  is  likely  to  be  long  postponed 
after  the  first. signs  of  rupture,  and  the  column  will  sustain  greatly 
increased  loads  even  after  the  entire  failure  of  the  shell  of  concrete 
■outside  the  bands." 

Considere  and  others  have  made  extensive  theoretical  and  experi- 
mental investigations  of  hooped  columns.  Considere  concludes  that 
the  ultimate  strength  is  given  by  the  formula 

P'=^fcA  +  2.4/.S  As, 
or,  since  p=  As/ A 

P'=fcA-\-2AfspA  (29) 

*  "Principles  of  Reinforced  Concrete  Construction,"  Chapter  III.  Turneaure  and 
Maurer. 


THEORY  AND  DESIGN. 


6/3 


Comparing  this  equation  with  equation  (28),  Article  552,  it  is  seen 
that  the  reinforcing  value  of  the  steel  is  2.4  times  as  much  as  in 
longitudinal  reinforcement. 

Some  cities  require  certain  formulas  to  be  used,  and  in  these 
cases  the  various  building  laws  must  be  consulted.  The  following 
formula  is  the  one  used  in  New  York  City  (Manhattan)  for  hooped 
columns : 

P'  (in  tons)  =0.8  7-2  +  80  -4^  r  +  3^,  (30) 

in  which 

P'=the  total  strength,  in  tons,  of  the  column  ; 
r=the  radius,  in  inches,  of  the  hoops  or  wrapping  surrounding 
the  concrete  core ; 

//h=the  area,  in  square  inches,  of  the  cross-section  of  one  hoop ; 
^=the  pitch  of  the  hoops ; 

^s=the  total  cross-sectional  area,  in  square  inches  of  the 
longitudinal  steel. 

This  formula  is  derived  from  a  general  formula  developed  by- 
Mr.  F.  H.  Dewey,  of  the  Bureau  of  Buildings,  Borough  of  Man- 
hattan, N.  Y.,  and  takes  this  form,  approximately,  when  /c=350, 
p  =  12  and  when  the  safe  unit  tensile  stress  in  the  steel  hoops  is 
taken  at  16,000  pounds  per  square  inch.* 

In  comparing  the  results  of  tests  made  on  full-sized  columns  with 
the  results  obtained  by  using  this  formula,  there  is  found  to  be  a 
close  correspondence. 

556.  DISPOSITION  AND  DETAILS  OF  WRAPPED  OR 
HOOPED  COLUMN  REINFORCEMENTS.— Steel  bands  or 
steel  wire  are  used  for  this  form  of  lateral  reinforcement.  With 
metal  bands  the  joints  are  rivetted,  and  these  joints  should  be  made 
as  strong  as  the  unrivetted  metal  itself.  In  the  case  of  wire  it  is 
wound  spirally  and  continuously  through  the  entire  column  length, 
with  the  ends  bent  down  far  enough  to  be  firmly  anchored  in  the 
concrete  when  poured  and  to  resist  the  tension  resulting  from  the 
lateral  stresses  developed  in  the  concrete. 

Two  methods  are  employed  for  the  details  of  wrapping  and  hoop- 
ing at  the  top  and  bottom  of  columns  at  the  floors.  One  omits  the 
wrapping  at  the  concrete  floor  construction  sections  in  order  to 
preserve  the  floor  and  column  concrete  bond.    The  method  pre- 

*  For  further  notes  on  the  derivation  and  limiting  conditions  of  the  above  formula, 
see  Chapter  XXIV,  in  the  "Architect's  and  Builder's  Pocket-Book,"  Frank  E.  Kidder. 


674 


BUILDING  CONSTRUCTION.  (Ch.  X) 


vails  in  cases  in  which  there  is  a  good  soHd  floor  construction 
around  the  column  ends.  The  other  method  involves  making  the 
wrapping  continuous  through  the  floor  construction. 

3.    MATERIALS  OF  REINFORCED  CONCRETE  CON- 
STRUCTION. 

557.  GENERAL  CONSIDERATIONS.— Concretes  in  general 
have  already  been  considered  in  the  first  general  subdivision  of 
this  chapter  and  elements  in  Chapter  IV.  It  remains  to  consider, 
(i)  those  special  details  and  requirements  of  concretes  pertaining 
to  their  use  in  reinforced  concrete  construction  and  (2)  the  prop- 
erties of  the  reinforcing  materials. 

558.  CONCRETES  IN  REINFORCED  CONSTRUCTION. 
— While  in  mass  concrete  construction  the  stability  of  the  structure 
depends  in  large  part  upon  the  mass  and  weight  of  the^  concrete, 
in  reinforced  concrete  construction  the  strength  of  the  materials  is 
of  greater  importance.  A  relatively  high  grade  of  concrete  should 
therefore  generally  be  used.  The  sections  of  the  constructive  mem- 
bers being  relatively  small,  and  the  stability  of  a  structure  being 
particularly  dependent  upon  the  integrity  of  every  one  of  its  parts, 
the  concrete  should  be  free  from  voids  and  of  uniform  quality 
throughout.  In  order  also  to  adhere  sufficiently  to  the  reinforce- 
ment and  to  furnish  adequate  protection  to  it  against  damage  by  fire 
or  by  corrosion,  it  should  be  thoroughly  sound.  The  greatest  care 
should  be  exercised  in  its  preparation  and  depositing  in  place,  and 
regular  and  systematic  tests  should  be  made  of  it  as  actually  used 
in  each  building  during  the  progress  of  the  work. 

559.  CEMENT  FOR  REINFORCED  CONCRETE  CON- 
STRUCTION.— Portland  cement  only  should  be  used,  and  it  should 
always  be  tested  and  made  to  meet  the  requirements  of  the  standard 
specifications.  (See  Articles  179  and  180.)  In  this  form  of  con- 
struction soundness,  or  constancy  of  volume,  is  particularly  impor- 
tant, as  unsound  cement  in  some  important  supporting  member,  such 
as  a  column,  may  endanger  an  entire  building;  and  the  time  of  set- 
ting, or  rapidity  of  hardening  also,  is  particularly  important,  as 
either  the  building  may  have  to  receive  a  heavy  load  at  an  early 
date  or  the  placing  of  such  load  may  be  long  deferred. 

560.  THE  AGGREGATE  IN  REINFORCED  CONCRETE 
CONSTRUCTION. — Aggregates  have  already  been  considered 
under  fire-proof  materials  and  under  concretes  in  general.  (See 


4 


MATERIALS. 


6/5 


Articles  412,  498  and  515.)  The  requirements  are  generally  the  same 
for  mass  concrete  and  reinforced  concrete  construction,  with  the 
exception  of  those  dealing  with  the  size  of  the  aggregates.  While 
in  large  masses  of  concrete  the  size  of  the  aggregates  in  largest 
diametrical  dimension  may  run  as  high  as  2^  inches,  as  in  thick 
walls,  large  piers,  foundations,  etc.,  the  common  maximum  sizes  in 
reinforced  work  are  from  ^  of  an  inch  to  inches. 

The  building  laws  of  many  cities  determine  the  maximum  sizes 
of  the  aggregate  to  be  used. 

Philadelphia  requires  that  ''when  stone  is  used  with  sand  or 
gravel  it  must  be  of  a  size  to  pass  through  a  one-inch  ring,  and  25 
per  cent  of  ti^e  whole  must  not  be  more  than  one-half  the  maximum 
size." 

New  York,  Chicago,  St.  Louis  and  Buffalo  require  that  the  stones 
shall  pass  through  a  ^-inch  ring. 

Cleveland  allows  a  ^-inch  stone  as  a  maximum  for  floors  and 
fire-proofing  and  a  2-inch  stone  for  other  kinds  of  concrete 
construction. 

San  Francisco  allows  a  i-inch  stone  as  a  maximum  for  floors  and 
fire-proofing  and  a  2-inch  stone  for  foundation  work. 

561.  THE  PROPORTIONS  OF  THE  MATERIALS  FOR 
REINFORCED  CONCRETE  CONSTRUCTION.— The  propor- 
tions depend  upon  the  character  and  size  of  the  materials  them- 
selves. Those  commonly  used  vary  from  about  1:2:4  to  1:3:6  of 
cement,  sand  and  broken  stone  or  gravel,  respectively.  In  many 
cities  the  building  laws  determine  the  proportions  to  be  used.  The 
1 :2 :4  mixture  is  used  more  than  any  other,  and  richer  mixtures 
than  this  are  not  common.  It  is  also  the  one  that  has  been  up  to 
this  time  the  most  frequently  used  in  tests  in  reinforced  concrete 
structural  members. 

These  customary  proportions  should  not  be  mistakingly  adopted, 
however,  in  all  cases  as  a  matter  of  course;  and  for  large  and 
important  operations  a  careful  study  of  the  materials  and  of  the 
best  proportions  to  use  for  economy  and  strength  should  be  made. 
For  any  given  materials  the  most  economical  mixture  is  in  general 
the  strongest. 

New  York  requires  that  "the  concrete  be  mixed  in  proportions  of 
one  of  cement,  two  of  sand  and  four  of  stone  or  gravel ;  or  the 
proportions  may  be  such  that  the  resistance  of  the  concrete  to 


676  BUILDING  CONSTRUCTION.  (Ch.  X) 


crushing  shall  not  be  less  than  2,000  pounds  per  square  inch  after 
hardening  for  twenty-eight  days.  The  tests  to  determine  this  value 
must  be  made  under  the  direction  of  the  Superintendent  of 
Buildings." 

The  requirements  of  St.  Louis  are  the  same  as  those  for  New- 
York. 

Philadelphia  requires  a  1  '.2:4  mixture. 
Chicago  requires  a  i  13  15  mixture. 

Boston  and  San  Francisco  require  a  mixture  of  one  of  cement 
to  six  of  aggregate. 

Cleveland  requires  no  special  mixture,  but  demands  a  resistance 
to  crushing  the  same  as  that  required  by  New  York  an^  St.  Louis. 

Buffalo  requires  a  1:2:5  mixture. 

Although  in  the  requirements  of  the  above-mentioned  cities  the 
proportions  are  not  the  same  in  all,  they  all  demand,  however,  a 
crushing  strength  of  2,000  pounds  per  square  inch  developed  after 
twenty-eight  days,  and  no  mixtures  that  will  not  show  this  should 
ever  be  used. 

562.  THE  CONSISTENCY  OF  CONCRETE  IN  REIN- 
FORCED CONSTRUCTION.— Concrete  mixtures  range  from 
very  dry  to  very  wet,  according  to  the  amount  of  water  used ;  and 
the  purpose  for  which  the  concrete  is  employed  regulates  the  con- 
sistency. The  latest  practice  tends  toward  what  is  known  as  a 
"wet"  mixture  for  use  in  reinforced  work,  a  mixture  of  about  the 
consistency  of  molasses  and  one  which  can  be  readily  worked  into 
place  in  the  forms  and  around  the  reinforcements.  Although  thor- 
oughly tamped  and  relatively  dry  concrete  shows  a  slightly  greater 
strength  than  a  wet  mixture,  better  results  are  usually  obtained  with 
the  latter  because  of  the  difficulty  and  expense  of  securing  a  neces- 
sary amount  of  dry  mixture  tamping;  and  this  is  especially  the 
case  where  a  dense,  homogeneous  concrete  is  required.  Reliability 
is  more  important  than  maximum  strength  in  reinforced  concrete 
construction.  A  dry  mixture  is  relatively  stronger,  but  demands 
more  careful  inspection  when  being  put  in  place ;  a  wet  mixture  is 
relatively  weaker  and  demands  a  prompt  pouring  into  the  molds 
to  counteract  the  tendency  of  the  materials  to  segregate ;  but,  on 
the  whole,  it  gives  better  results. 

563.  STRENGTH  AND  ELASTIC  PROPERTIES  OF 
CONCRETE   IN   REINFORCED    CONSTRUCTION.— These 


MATERIALS. 


677 


have  already  been  considered  under  concretes  in  general,  mass  con- 
crete construction  and  under  the  general  theory  and  design  of  rein- 
forced concrete  construction.  (See  especially  Articles  503,  504,  515, 
529  and  530.) 

564.  REINFORCING  MATERIALS  IN  CONCRETE  CON- 
STRUCTION.— Steel  is  now  universally  used  as  the  reinforcing 
material  for  concrete  construction.  It  is  placed  in  various  forms 
near  the  tension  sides  of  structural  members  to  resist  the  tensional 
stresses.  It  may  assist  also  in  resisting  the  shear,  the  diagonal 
tension  and  occasionally  the  compression  stresses,  as  in  doubly 
reinforced  beams ;  and  it  gives  additional  compressive  strength  when 
used  in  columns. 

565.  GENERAL    QUALITIES    AND    PROPERTIES  OF 

THE  STEEL. — The  following  is  a  convenient  classification  of  * 
the  various  grades  of  steel  as  a  building  material : 

Soft.  Medium.  Hard. 

Elastic  limit,  lbs.  per  sq.  in   30 — 35,000  35 — 40,000  50 —  60,000 

Ultimate  strength,  lbs.  per  sq.  in..  50 — 60,000  60 — 70,000        80 — 100,000 

For  all  structural  shapes  the  medium  or  mild  steel  is  used,  and 
for  reinforced  concrete  work  various  grades  have  been  used  ranging 
from  soft  to  quite  hard.  Authorities  still  differ  regarding  the 
question  of  the  grade  best  suited  to  reinforced  work. 

"There  exists  considerable  difference  of  opinion  as  to  the  quality 
of  steel  to  be  desired,  especially  with  reference  to  the  use  of  soft 
or  hard  material,  or  steel  with  low  or  high  elastic  limits.  Certainly 
a  material  as  hard  as  that  formerly  demonstrated  'hard  bridge 
steel'  is  entirely  suitable  for  reinforced  construction.  Such  material 
has  an  elastic  limit  of  about  40,000  pounds  per  square  inch.  Much 
material  has  been  used  of  an  elastic  limit  of  45,000  to  50,000  pounds 
per  square  inch  and  even  higher,  but  a  value  beyond  this  is  not  to 
be  desired.  An  elastic  limit  of  45,000  pounds  per  square  inch  is 
three  times  the  working  stress  of  15,000  pounds  per  square  inch. 
The  use  of  steel  with  an  elastic  limit  higher  than  this  is  unnecessary, 
and  is  of  doubtful  wisdom,  as  the  ductility  of  a  higher  steel  of 
the  usual  quality  is  not  high.  The  authors  would  suggest  a  mate- 
rial of  the  quality  employed  for  buildings  with  an  elastic  limit  of 
from  35,000  to  40,000  pounds  per  square  inch  and  working  stresses 
of  from  12,000  to  14,000  pounds  per  square  inch."* 


*  'Principles  of  Reinforced  Concrete  Construction."     Turneaure  and  J.Iuarer. 


678 


BUILDING  CONSTRUCTION. 


(Cn.  X) 


''High  carbon  steel  has  a  greater  percentage  of  carbon  and  is 
therefore  more  brittle.  The  use  of  high  carbon  steel  would  permit 
greater  stresses  in  the  reinforcement  and  consequently  a  less  amount 
of  steel  and  a  greater  economy  in  construction.  On  account  of  its 
greater  brittleness,  however,  it  is  liable  to  sudden  failures  under 
stress.  It  is  also  often  found  to  be  cracked  or  broken  when  sent 
to  the  work,  and  unless  very  carefully  inspected  there  is  great  lia- 
bility of  defective  material  getting  into  the  structure.  Furthermore, 
much  of  the*  so-called  high  carbon  steel  in  practice  has  been  found 
upon  test  to  fall  far  short  of  the  specifications.  lis  use  is  there- 
fore to  be  .avoided,  unless  special  care  is  taken  to  secure  an  abso- 
lutely reliable  article  and  to  have  it  inspected  and  tested.  For 
large  important  work  this  would  be  desirable.  Ordinarily,  how- 
ever, mild  steel  should  be  used,  as  commercially  it  is  manufactured 
and  sold  under  such  standard  conditions  that  it  is  reliable.  As  the 
modulus  of  elasticity  of  high  carbon  steel  is  practically  the  same  as 
that  of  medium  steel,  the  deformation  under  any  given  loading  is 
the  same  and  there  is  no  special  advantage  in  the  use  of  one  over  the 
other. 

''The  generally  accepted  working  stresses  for  medium  steel  are 
16,000  pounds  per  square  inch  in  tension  and  10,000  pounds  per 
square  inch  in  shear.  Tests  have  shown  that  in  cases  where  the 
failure  of  reinforced  concrete  beams  is  due  to  the  failure  of  the 
reinforcement,  the  stress  in  the  metal  had  not  more  than  reached 
the  yield  point.  This  point  is  somewhat  lower  than  the  elastic 
limit.  The  working  stress  in  the  steel,  therefore,  should  be  a  fixed 
proportion  of  the  yield  point  or  the  elastic  limit.  It  is  held  by 
some  that  this  ratio  should  not  be  as  high  as  one  to  two,  but  more 
nearly  one  to  three,  reducing  the  working  stress  in  mild  steel  as 
given  above  to  from  10,000  to  12,000  pounds  per  square  inch.  In 
using  high  carbon  steel  they  would  advocate  a  similar  ratio  of  the 
elastic  limit,  whatever  that  may  be,  according  to  test.  Ordinarily 
20,000  pounds  per  square  inch  is  taken  as  the  zvorking  stress  for 
high  carbon  steel."* 

For  the  working  unit  tensile  and  shearing  stresses  allowed  by  the 
building  laws  of  the  larger  cities  of  the  United  States,  for  steel  in 
reinforced  concrete  construction,  see  Table  XLI,  Article  542. 


*  Rudolph  P.  Miller  in  Chapter  XXIV  of  the  "Architect's  and  Builder's  Pocket- 
Book,"  by  Frank  £.  Kidder. 


TYPES  OF  REINFORCEMENTS. 


679 


Modulus  of  Elasticity  of  Steel. — This  is  approximately  the  same 
for  all  grades  of  steel  and  is  generally  taken  at  30,000,000  pounds 
per  square  inch. 

Elastic  Elongation  of  Steel. — The  elongation  of  the  steel  at  its 
elastic  limit  is  considered  in  determining  the  deformations,  and  for 
the  three  grades  of  steel  and  the  modulus  of  elasticity  given  above 
the  elongations  per  unit  of  length  at  the  elastic  limit  are  as  follows : 

For  soft  steel   0.0010  —  0.0012 

For  medium  steel   0.0012  —  0.0013 

For  hard  steel   0.0017  —  0.0020 

CoeMcient  of  Expansion. — The  coefificient  of  expansion  of  steel 
may  be  taken  at  0.0000065  per  1°  Fahr. 

566.  PROPERTIES  OF  CONCRETE  AND  STEEL  IN 
COMBINATION. — These  include  the  adhesion  of  the  concrete 
and  the  reinforcements,  the  mechanical  bond,  the  ratio  of  the 
moduluses  of  elasticity,  the  tensile  strength  and  elongation  of  con- 
crete when  reinforced  and  the  relative  contraction  and  expansion 
due  to  temperature  or  shrinkage. 

The  most  important  of  these  have  already  been  discussed  under 
general  theory  and  design  and  elsewhere,  and  for  any  further  con- 
sideration of  the  subjects  the  reader  is  referred  to  the  various 
treatises  on  the  theory  of  reinforced  concrete  construction. 

4.    TYPES  OF  REINFORCEMENTS. 

567.  GENERAL  CONSIDERATIONS.— The  rapid  develop- 
ment oi  reinforced  concrete  construction  has  resulted  in  the  intro- 
duction of  numerous  shapes  and  combinations  of  bars  and  rods, 
many  of  them  patented  and  some  of  them  used  as  the  elements 
of  mor,e  or  less  complete  systems  of  reinforcement. 

The  form  and  size  of  reinforcing  steel  must  be  such  as  will  allow 
it  to  be  readily  incorporated  into  the  concrete  and  to  form  a  mono- 
lithic structure.  Comparatively  small  cross-sections  of  steel  mem- 
bers are  required,  leading  to  the  use  of  rods  or  bars  varying  in 
<:ross-sectional  size  from  ^  to  ^  of  an  inch  for  light  work  up 
to  to  2  inches  for  heavy  girders  and  columns.  Cross-sectional 
sizes  usually  refer  to  the  cross-sections  of  square  bars  of  corre- 
sponding sizes. 

568.  GENERAL  CLASSES  OF  REINFORCEMENTS.— Re- 
inforcements may  be  classified  generally  as  follows : 


68o  BUILDING  CONSTRUCTION.  (Ch.  X) 

1.  Unframed  bars  or  rods; 

(1)  Plain, 

(2)  Deformed, 

(3)  With  stirrup  or  truss  attachments. 

2.  Framed  or  tied  bars  or  rods  forming  so-called  "Unit  Sys- 
tems"; * 

(1)  Plain  bars  or  rods, 

(2)  Deformed  bars  or  rods.  v 

569.  PLAIN  REINFORCING  BARS  AND  RODS.— The 
shape  of  the  cross-section  of  plain  bars  is  round,  square,  rectangular, 
angle-shaped,  T-shaped,  cruciform,  I-shaped,  etc. 

Plain  round  bars  have  been  used  in  Europe  and  the  United  States 
for  many  years.  Square  bars  are  not  so  easily  obtained  nor  as 
convenient  in  use  as  round  bars,  but  they  show  about  the  same 
adhesive  strength  as  round  bars.  Rectangular  cross-sectioned  or 
flat  bars  are  not  considered  desirable,  their  adhesion  to  the  concrete 
being  considerably  below  that  of  round  or  square  bars ;  and  it  is 
claimed  by  some  that  square  and  other  sharp-ddged  bars  cause  a 
tendency  to  start  initial  cracks  in  the  concrete  during  the  setting 
shrinkage. 

When  plain  bars  are  used  either  the  adhesion  alone  of  the  steel 
and  concrete  is  depended  upon  for  the  transmission  of  stress,  or  the 
ends  of  the  bars  are  anchored  into  the  concrete,  thus  developing 
nearly  their  full  tensile  strength. 

570.  DEFORMED  REINFORCING  BARS  AND  RODS.— 
Many  special  shapes  of  bars  have  been  devised,  the  principal  object 
of  which  is  to  supplement  the  adhesion  by  a  bonding  of  the  materials, 
usually  called  a  "mechanical  bond." 

The  immediately  following  articles  briefly  describe  and  illustrate 
some  of  the  forms  used.  It  is  not  possible  to  describe  and  illustrate 
all  of  them,  and  those  mentioned  do  not  by  any  means  exhaust  the 
list  of  excellent  reinforcements  on  the  market. 

571.  COLD-TWISTED  LUG  BAR.— Fig.  504  shows  the  cold- 
twisted  lug  bar,  a  bar  with  small  lugs  or  projections  placed  at  reg- 
ular intervals.  It  is  manufactured  by  the  General  Fire-proofing 
Company,  Youngstown,  Ohio,  in  various  sizes  of  cross-sectional 
area  corresponding  to:  j^,  ^,  ^,  }i,  J^,-  i,  i/^  and  1^4 -inch 
square  bars.  The  manufacturers  of  this  bar  claim  that  the  elastic 
limit  and  ultimate  strength  are  increased    and    the  elongation 


TYPES  OF  REINFORCEMENTS. 


68i 


decreased  by  the  twisting,  and  that  the  tendency  to  untwist  under 
tensional  stress  is  diminished  by  the  higs. 

572.  CUP  BAR. — Fig.  505  shows  the  cup  bar,  made  by  the 
Trussed  Concrete  Steel  Company,  Detroit,  ]\lich.,  and  con- 
structed with  projecting  longitudinal  ribs  and  transverse  divisions, 


Fig.   504.     Cold-twisted  Lug  Bar. 


which  form  hollows  or  *'cups"  to  be  filled  with  the  surrounding 
concrete,  and  thus  to  aid  in  resisting  the  tendency  to  slip  or  to  pull 
out,  and  also  the  tendency  to  shear  the  concrete  near  and  along 
the  bar. 

573.  DE  MAN  BAR.— Fig.  506  shows  the  De  Man  bar,  a  flat 
bar,  A,  with  twists,  B,  at  short  intervals  of  from  2  to  4  inches, 
according  to  the  size  of  the  bars,  which  varies  from  to  ^  of  an 
inch  in  thickness  and  from  ^4  of  i"ch  io  lYz  inches  in  width. 
The  purpose  of  the  undulating  twists  is  to  strengthen  the  bond. 


Fig.   50.5-     Cup  Bar. 


574.  DIAMOND  BAR.— Fig.  507  shows  the  diamond  bar, 
invented  by  Mr.  William  Mueser  and  manufactured  by  the  Con- 
crete Steel  Engineering  Company,  New  York,  in  sizes  varying  from 
J4  of  an  inch  up  to  1%  inches,  the  weights  and  areas  being  reckoned 
equal  to  those  of  plain  square  bars  of  like  denominations.  The  prin- 
cipal advantages  claimed  for  this  bar  are  the  uniform  areas  of  the 
cross-sections  and  the  saving  of  any  waste  of  steel  used  to  make 
deformations  for  the  sole  purpose  of  forming  a  bond.  It  is  one  of 
the  most  recent  types  of  rolled  bars. 


682  BUILDING  CONSTRUCTION.  (Ch.  X) 


575.  JOHNSON  CORRUGATED  BAR.— Figs.  508,  509,  510 
and  511  show  the  Johnson  corrugated  bar,  a  patented  bar,  invented 

by  Mr,  A.  L.  Johnson  and  made  by 
the  Expanded  Metal  and  Corrugated 
Bar  Company,  St.  Louis,  Mo.  The 
corrugations  are  arranged  as  shown, 
to  efifect  the  mechanical  bond ;  and  the 
alternating  of  their  positions  leaves 
the  effective  area  the  same  through- 
out. These  bars  are  rolled  to  vari- 
ous sizes  and  weights,  and  are  of  four 
types,  as  follows  :  "corrugated  rounds" 
shown  in  Fig.  508 ;  ''corrugated 
squares,  new  style,''  shown  in  Fig. 
509 ;  "corrugated  squares,  old  style," 
shown  in  Fig.  510;  and  ''corrugated 
flats,  universal  type,"  shown  in  Fig. 
511.    (See  also  Article  599.) 

576.  PRIDDLE  BAR.— Fig.  512 
shows  the  Priddle  "inner  or  internal 
bond  bar"  for  concrete  reinforcement, 
patented  by  Mr.  Arthur  Priddle,  San  Francisco,  Cal.  Flanged 
slits  are  made  in  the  flat  bar,  and  there  is  no  loss  in  cross- 
sectional  area.  The  manufacturers  claim  that  the  bar  is  a  positive 
tie,  does  not  depend  upon  the  mechanical  bond  of  the  concrete  and 
therefore  requires  a  relatively  small  amount  of  metal. 


Fig.  507.     Diamond  Bar. 


577.    RANSOME  BAR. — Fig.  513  shows  the  Ransome  twisted 
bar.    It  is  one  of  the  oldest  types  of  reinforcing  steel  and  was 
invented  by  Mr.  E.  L.  Ransome,  of  the  Ransome  &  Smith  Company, 
and  used  as  long  ago  as  1894.   The  patents,  on  these  bars,  which  are 
manufactured  from  square  bars  twisted  cold,  have  now  expired. 


Fig.  506.     De  Man  Undulated  Bar. 


TYPES  OF  REINFORCEMENTS. 


683 


-and  any  one  may  make,  sell  or  use  them.  The  Ransome  Concrete 
Machinery  Company,  New  York,  has  all  the  special  machinery  and 
facilities  for  furnishing  them,  and  they  are  made  in  many  sizes. 


Fig.   508.     Johnson  Bar.     Corrugated  Rounds. 


Fig.  509.    Johnson  Bar.     Corrugated  Squares.     New  Style. 


BiiBLJi 


Fig.  510.    Johnson  Bar.    Corrugated  Squares.    Old  Style, 


Fig.   511.     Johnson  Bar.     Corrugated  Flats,  Universal  Type. 

from  to  134-iiich,  and  larger  when  required.  A  working  tensile 
stress  of  about  20,000  pounds  per  square  inch  is  generally  assumed, 
as  the  tensile  strength  is  increased  by  the  twisting. 


Fig.   512.     Priddle  Inner  Bond  Bar. 


Although  for  convenience  this  bar  is  mentioned  here  with  the 
deformed  reinforcing  bars  and  rods,  it  is  not,  strictly  speaking,  a 
"''deformed"  bar. 


684 


BUILDING  CONSTRUCTION. 


(Ch.  X)^ 


578.  THACHER  BAR.— Fig.  514  shows  the  Thacher  bar,  some- 
times called  the  Thacher  ''bulb"  bar,  invented  and  patented  by  Mr. 
Edwin  Thacher,  of  the  Concrete  Steel  Engineering  Company,  New 
York;  used  extensively  in  buildings,  but  particularly  in  arches  and 
bridges ;  and  now  largely  superseded  by  the  Diamond  bar,  made  by 
the  same  manufacturers,  and  described  in  Article  574.  It  is  rerolled 
from  round  bars  to  the  shape  indicated. 


579.  BARS  WITH  STIRRUP  AND  TRUSS  ATTACH- 
MENTS.— There  are  several  types  of  reinforcements  in  which  plain 


bars  are  generally  used,  with  various  systems  of  stirrup  connec- 
tions, bendings  and  trussing  of  the  bars,  etc. ;  and  with  different 
methods  of  securing  and  anchoring  the  members  in  the  concrete 
or  at  the  supports.  The*  Golding,  Hennebique,  Kahn,  etc.,  systems 
are  illustrations  of  this  .  type. 

580.  GOLDING  BAR.— Fig.  515  shows  the  ''Golding  monolith 
steel  bar,"  manufactured  by  the  Monolith  Steel  Company  of  Wash- 
ington, D.  C,  and  the  invention  of  Mr.  J.  F.  Golding.  It  is  a 
"plain"  bar  and  the  side  grooves  serve  to  hold  the  stirrups  as  well 
as  to  increase  the  surface  in  contact  with  the  concrete.    The  cross- 


section  is  uniform  in  shape  throughout,  except  at  the  joining  of  the^ 
stirrups,  where  the  change  in  shape  only  is  slight.  The  stirrups  will 
tear  apart  before  separating  from  the  bar.  They  may  be  placed  and 
spaced  wherever  desired.  These  bars  may  be  had  in  sizes  equiva- 
lent to  iy2,  I,  8/10  and  J^-inch  square  bars;  giving  areas  equal, 
respectively,  to  214.  64/100  and  ^  square  inches;  and  having 
web  members  of,  respectively,  Yi,  Y^,  Ya  and  -^Q-sxzt. 


581.  HENNEBIQUE  SYSTEM.— Fig.  516  shows  the  bars 
and  stirrups  and  their  general  arrangement  in  the  Hennebique  sys- 


Fig.  513.     Ransome  Twisted  Bar. 


Fig.   514.     Thacher  Bulb  Bar. 


TYPES  OF  REINFORCEMENTS.  685 


teni  of  beam  and  girder  reinforcement.  Plain  bars  are  used  in  the 
construction  shown  and  their  ends  are  spht  and  flared  out  to  form 


angle-brackets  and  securing  them  with  nuts,  etc.  (See  Articles  590 
and  603.) 

582.  KAHN  BAR. — Fig.  517  shows  in  perspective  the  general 
type  of  the  Kahn  trussed  bar  made  by  the  Trussed  Concrete  Steel 
Company,  Detroit,  Mich.,  with  cross-section  of  bar  and  with  dia- 
grams showing  analogy  to  truss  action  and  general  method  of  using 
the  bars  in  beam  and  floor  construction.  (See  also  Figs.  29  and  30.) 
The  stirrups  are  parts  of  the  reinforcing  bar  itself,  which  is  a 
square  bar  placed  with  the  diagonals  vertical  and  horizontal  and 
having  webs  rolled  on  the  two  side  edges.  The  shearing  of  these 
webs  along  a  part  of  their  length  and  the  bending  up  of  the  sheared 
portions  form  the  stirrups,  which  may  turn  up  in  pairs  as  shown 
in  the  figure  or  in  alternating  single  stirrups  to  make  closer  spacing. 

The  positive  security  of  the  stirrups  and  the  location  of  the  max- 
imum cross-sections  of  metal  at  the  points  of  greatest  bending 
moment  are  two  important  advantages  of  this  system.  Two  of  the 
disadvantages  which  are  mentioned  are,  for  deep  beams,  the 
difficulty  of  making  the  stirrups  long  enough  and,  in  all  beams,  the 
tendency  of  the  webs  to  divide  the  concrete  into  two  parts  or 
layers. 

Fig.  518  is  a  diagram  section  of  the  Kahn  bar  used  for  conven- 
ience in  figuring  sizes.  The  following  are  the  sizes  in  which  it  is 
made : 


Fig.  515.    Golding  Monolith  Steel  Bar. 


an  anchorage  in  the  concrete 
over  the  supports.  Other 
methods  of  anchoring  the  ten- 
sion bars  are  employed  in 
various  constructions,  such  as 
bending  the  ends  of  the  bars, 
using  nuts  and  washers,  run- 
ning the  bars  through  steel 
column  web-plates  or  through 


Size. 


A 
3 


B 

V4 


c 

Va 


Weight 
per  foot. 


Area 


sq.  in. 


I 


4.8 
6.9 


1.4 
2.7 


0.38 
0.78 
1.42 


2.00 


686 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


TYPES  OF  REINFORCEMENTS. 


687' 


583.  STIRRUPS  IN  CONCRETE  REINFORCEAIENT.— 
These  are  used  vertically  or  diagonally  in  order  to  overcome  the 
tendency  in  loaded  beams  to  develop  diagonal  cracks  and  breaks 
near  the  supports.    These  failures  are  probably  due  partly  to  the 


PERSPECTIVE  ViEW  OF  SHEARED.  BAR, 


Fig.  517.     Kahn  Trussed  Bar.    Truss  Action  Diagram.     Floor  Construction. 


horizontal  and  vertical  shear,  which  is  a  maximum  at  the  sup- 
ports, and  partly  to  internal  tension  caused  by  a  stretching  and 
slipping  of  the  reinforcing  rods.  It  is  therefore  important  to 
attach  the  stirrups  securely  to  the  tension  rods,  firmly  anchor  them 
at  the  ends  and  secure  the  greatest  possible  adhesion  of  steel  to  con- 
crete by  mechanical  bond  or  otherwise. 

The  shear  or  diagonal  tension  has  already  been  discussed  in 
Article  548,  and  the  adhesion  of  the  concrete  to  the  reinforcement 
in  Article  550. 

584.    UNIT  SYSTEMS.— In  the  articles  treating  of  the  general 
theory  and  design  of  reinforced  concrete 
construction  the  importance  of  keeping  the 
reinforcement   in   an   exact  position  was 
^  explained.    It  is  for  the  purpose  of  main- 

^^^^^^^^  ^    taining  this  exact  position  of  the  reinforce- 

^        ^   ment  that  the  so-called  ''unit"  systems  are 
\^  ^  used.     These  unit  systems  consist  gener- 

g.  518.    Kahn  Trussed  Bar.   ally  of  the  liOHzontal  and  curved  and  bent 
Cross-section.  tcnsion  rods,  generally  not  deformed,  and 

the  stirrups,  all  framed  and  tied  together  into  one  unit,  so  that  they 
can  be  readily  set  in  their  exact  positions  and  kept  there,  with  little 


688 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


chance  of  their  moving  in  the  forms  while  the  concrete  is  being 
filled  in. 

Some  typical  unit  systems  are  described  and  illustrated  in  the 
following  articles.  There  are  other  excellent  systems  in  addition 
to  those  mentioned  to  illustrate  the  construction. 

585..  CUMxAIINGS  LOOP  TRUSS  UNIT  FRAME.— Fig.  519 
shows  the  Cummings  system  of  reinforcing  concrete  beams  and 
girders,  the  frames  being  manufactured  by  the  Electric  Welding 
Company,  Pittsburg,  Pa.  The  drawing  shows  it  in  position,  as 
used,  as  at  A  and  B,  and  closed  or  ''knocked  down"  flat  for  con- 
venience and  economy  in  shipping,  as  at  C,  D  and  E.  Inverted 
U-shaped  stirrups  are  attached  to  the  longitudinal  bars  and  secured 
to  them  by  patent  "chair-locks"  or  "saddles."  (See  also  Article  598.) 

586.    ECONOMY  UNIT  FRAME.— Figs.  520  to  524  show  this 


Fig.  519.    Cummings  Loop  Truss  Frame. 


collapsible  frame,  with  details  also  of  floor  slab  reinforcing.  It 
is  manufactured  by  the  Expanded  Metal  and  Corrugated  Bar  Com- 
pany, St.  Louis,  Mo.  It  is  easily  shipped  and  placed  in  the  form 
as  a  unit,  with  the  stirrups  definitely  spaced  and  provided  with 
separators,  which  accurately  fix  and  hold  the  main  reinforcing  bars 
in  position. 

Fig.  520  shows  bars  in  place  in  stirrup  frame  ready  for  con- 
creting. 

Fig.  521  shows  frame  collapsed,  ready  for  shipping. 

Fig.  522  shows  a  cross-section  through  a  concrete  beam  and 
the  Economy  unit  frame ;  and  also  shows  plan  and  elevation  of 
saddle  or  separator,  which  is  slotted  to  receive  the  bars. 

Fig.  523  shows  section  and  perspective  of  concrete  floor  slab  with 
method  of  spacing  the  reinforcing  rods  with  spring  lock  bar  spacer, 
made  of  steel  wire  and  sprung  over  the  bars. 


690 


BUILDING  CONSTRUCTION.  (Ch.  X> 


Fig.  524  shows  cross-section  through  concrete  floor  slab,  wood 
centering  and  slab  rods  and  shows  also  the  stool-lock  spacers  used 


Section  Through  Beam.  Plain  and  Elevation  of  Saddle. 

Fig.   522.     Economy  Unit  Frame. 


not  only  to  separate  and  hold  the  slab  rods,  but  also  to  keep  the 
rods  at  a  certain  fixed  distance  above  the  wooden  centers  and  the 
lower  surface  of  the  concrete  slab. 


Fig.  523,    Concrete  Floor  Slab  with  Reinforging  Rods  and  Spring-lock  Bar  Spacers. 

The  rods,  spacers,  etc.,  shown  are  made  by  the  manufacturers  of 
the  Economy  unit  frame. 
587.    PIN-CONNECTED  GIRDER  FRAME.— Figs.  525  and 


TYPES  OF  REINFORCEMENTS.  691 

526  show  the  pin-connected  girder  frame  manufactured  by  the 
General  Fire-proofing  Company,  Youngstown,  Ohio. 

Fig.  525  shows  the  assembled  work  of  the  frame  for  the  girder 


Fig.  524.     Rods  and  Stool-lock  Spacers  for  Concrete  Floor  Slabs. 


and  the  connections  at  the  columns,  and  Fig.  526  shows  a  section 
through  reinforced  concrete  girder  and  columns  with  the  frame 
and  connections  in  place. 


Fig.   525.     Pin-connected   Girder  Frame. 


In  this  frame  some  of  the  reinforcing  bars  run  horizontally  near 
the  lower  surface  of  the  girder  from  column  to  column,  while  some 


Fig.  526.    Concrete  Girder  and  Columns  with  Pin-connected  Frame. 


are  bent  up  toward  the  supports,  as  shown,  and  are  bolted  together 
over  them  by  means  of  links  and  pins,  thus  making  a  rigid  con- 
tinuous framework  of  steel  from  wall  to  wall.    The  disposition  of 


692 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


the  stirrups  is  regulated  by  the  varying  requirements  of  different 
cases. 


588.    UNIT  CONCRETE-STEEL  FRAME.— Figs.  527,  528 


and  530  show  the  unit  girder  frame  in  perspective  and  in  sec- 
tions, and  Fig.  529  shows  the  unit  socket  used  to  support  the 
frame.  These  unit  frames  and  accessories  are  manufactured  by  the 
Unit  Concrete  Steel  Frame  Company,  Philadelphia,  Pa. 

Fig.  527  shows  the  original  general  arrangement  of  the  unit  type 
of  reinforced  girder  construction.  Some  of  the  longitudinal  bars 
are  bent  up  before  they  reach  the  supports.  The  stirrups  are 
U-shaped  and  have  holes  punched  through  them  near  their  upper 
ends  to  receive  the  rods  for  the  floor  slabs.  These  frames,  which 
are  designed,  built,  delivered,  erected  and  supported  as  units,  are 
specially  designed  for  each  span,  each  member  being  made  the 
necessary  size  and  shape,  with  tension  and  shear  members  properly 
spaced.    The  concrete  can  be  readily  tamped  with  little  or  no  dis- 


turbance of  the  reinforcing  members.  The  frames  are  easily 
adapted  to  any  system  of  slab  reinforcement,  which  is  always  laced 
through  the  stirrups,  making  a  T-sectional  construction. 

Fig.  528  shows  longitudinal  section  and  cross-sections  through  a 
unit  girder  frame  of  ordinary  and  usual  width. 

Fig.  529  shows  the  patented  unit  socket  used  to  support  the 
frame.  It  is  designed  to  locate  the  center  of  action  of  the  steel 
reinforcement  before  the  concrete  is  put  into  the  molds ;  to  allow 
inspection  before  concreting;  to  prevent  any  movement  from  the 
tamping;  and  to  furnish  supports  for  any  required  suspended  ceil- 
ings, partitions,  shafting,  pipes,  fixtures,  etc.,  without  the  use  of 
expansion-bolts. 

Fig.  530  shows  an  isometric  perspective  view,  looking  up,  of  a 
portion  of  reinforced  concrete  floor  slabs,  beams,  girders  and  col- 
umns, with  the  unit  concrete-steel  frame  system  of  construction. 
The  design  shown  is  for  heavy  floor  loads. 


f//y/T  C7/eDt2  /Pant  r^i^'Crn 
Fig.  527.     Unit  Girder  Frame.     General  Construction. 


TYPES  OF  REINFORCEMENTS. 


Fig.    530,     Unit   Girder   Frame  Construction. 


COLUMNS  AND  PIERS. 


695 


589.  CONCRETE  COLUMN  AND  PIER  REINFORCE- 
MENT.— The  following-  articles  describe  and  illustrate  some  of 
the  concrete  column  and  pier  reinforcements.  By  referring  also  to 
the  articles  dealing  with  the  different  types  and  kinds  of  reinforced 
concrete  construction  in  the  following  fifth  subdivision  of  this 
chapter,  the  reader  will  find  additional  illustrations  of  concrete  col- 
umn reinforcement  in  the  figures  showing  the  general  beam,  girder 
and  floor  construction. 

590.  ILLUSTRATIVE  EXAMPLES  OF  CONCRETE 
COLUMN  REINFORCEMENT.— Fig.  531  shows  the  Henne- 
bique  column  reinforcement,  with  illustration  of  lower  end  of 
column  and  footing  connection.    The  rods  are  imbedded  in  the 


concrete  near  the  periphery.  They  are  connected  by  means  of  ties 
of  hoop-iron  or  wire.  Thus  the  radius  of  gyration  is  increased 
and  the  rods  take  care  of  the  tensile  stresses  which  occur  from 
eccentric  loading  or  from  buckling  of  the  columns.  The  horizontal 
ties  prevent  the  buckling  of  the  rods  and  increase  the  strength  of 
the  concrete.  They  form  a  hooped  column,  the  properties  of  which 
have  been  investigated  by  M.  Considere  and  others. 

The  footing  of  the  column  is  also  of  a  very  simple  construction. 
Steel  rods,  carefully  placed,  form  with  the  concrete  a  flat  plate 
which  distributes  the  load  equally  over  the  soil.  (See  also  Articles 
581  and  603.) 

Fig.  532*  shows  the  column  reinforcement,  footing  connections 
and  footings  for  the  interior  columns  of  the  Bullock  Electric  Com- 


Fig.   531.     Hennebique  Column  and  Footing 
Reinforcement. 


*  Courtesy  of  the  Atlas  Portland  Cement  Company,  New  York. 


696  BUILDING  CONSTRUCTION.  (Ch.  X) 


pany's  machine  shop,  at  Norwood,  Ohio,  erected  by  the  Ferro 
Concrete  Construction  Company,  Cincinnati,  Ohio. 

Fig.  533  shows  the  Cummings  hooped  column.  Hooped  concrete 
columns  were  first  used  in  the  United  States  by  Mr.  Robert  A. 
Cummings.    (See  also  Article  598.) 

The  hooped  columns  of  individual  steel  hoops  are  horizontally 
spaced  upon  vertical  spacing  members  at  regular  distances,  usually 
two  or  three  inches.  For  small-size  hooping  the  spacing  verticals 
consist  of  flat  steel  strips  with  projections  arranged  to  clinch  both 
top  and  bottom  of  each  band,  thus  constituting  a  secure  and  rigid 


Fig.    532.     Column    and    Footing  Reinforcement, 
Bullock    Electric   Company's    Buildings,  Nor- 
wood, Ohio. 


II  ll 

'rn=i 

Lj_ji 

Fig.  533.    Cummings  Hooped 
Column. 


fastening.  For  heavy  hooping  the  spacing  verticals  may  be  of 
structural  steel  punched  for  staple  fastenings. 

Fig.  534  shows  the  column  hooping  and  spacing  bar  made  by  the 
Trussed  Concrete  Steel  Company,  Detroit,  Mich.  The  standard 
pitches  are  i,  2,  3,  4,  5  and  6  inches  and  the  hooping  material 
either  No.  O  wire  or  ^  by  34-ii'ich  bands. 

The  spacing  bar  is  provided  with  a  projecting  rib,  which  is 
sheared  from  the  main  section  to  form  projecting  fins.  The  spacing 
of  these  fins  corresponds  to  the  standard  pitch  of  the  hooping  bands 
and  when  bent  around  the  bands,  spaces  and  holds  the  hooping  in 
exact  position. 

Hooping  material  is  rolled  at  the  shops  to  various  diameters ;  and 


COLUMXS  AND  PIERS. 


697 


the  proper  number  of  coils  in  a  continuous  piece  can  be  supplied 
when  the  pitch  and  story-heights  are  known. 

In  assembling  the  reinforcement  for  a  hooped  column  four  or 
more  spacing  bars  are  placed  on  a  circular  form,  with  the  fin  side 
outward.  The  hooping  is  then  slipped  on  and  each  band  is  placed 
so  that  the  fins  can  be  bent  around  it  and  thus  hold  it  rigidly  in 
position.  The  longitudinal  reinforcing  bars  are  then  placed  inside 
the  core  and  wired  to  the  shell  at  three  or  more  points.  The  entire 
reinforcement  for  the  column  is  then  placed  as  a  unit  in  the  work. 

Fig.  535  shows  the  system  of  concrete  column  reinforcement 


Fig.    534.      Column    Hooping  and 
Spacing  Bar. 


introduced  by  the  Hinchman-Renton  Fire-proofing  Company,  Den- 
ver, Col. 

Fig.  536  shows  the  system  of  concrete  column  reinforcement  used 
by  the  American  Steel  and  Wire  Company,  New  York  and  Chicago. 
The  first  illustration  shows  the  arrangement  for  a  square  column 
and  the  second  the  arrangement  for  a  round  column.  The  tri- 
angular mesh  steel  wire  is  used  and  is  made  with  hinged  joints  on 
longitudinals,  either  4  or  8  inches  apart.    The  reinforcing  material 


•698 


BUILDING  CONSTRUCTION.  (Ch.  X) 


can  be  readily  formed  into  triangular,  round  or  irregular-shaped 
cages  without  bending  the  wires. 

Fig.  537  shows  a  detail  of  a  wall  col- 
umn or  pier  of  the  Salem  Laundry  build- 
ing, Salem,  Mass.,  designed  by  Ballinger 
&  Perrot,  Philadelphia,  Pa. 

The  exterior  walls  are  a  combination 
of  concrete  blocks  and  monolithic  con- 
crete, the  wall  columns  being  built  up 
of  blocks,  while  the  base-course,  the 
panels  under  the  windows  and  the  cor- 
nices, including  the  name  and  date  in- 
scriptions, were  cast  in  position.  The 
blocks  are  composed  of  what  is  known 
as  "dry  mixture"  of  i  part  of  cement 
and  3  parts  of  sand,  and  were  made  near 
the  building  site,  as  needed,  being  al- 
lowed to  season  from  ten  days  to  two 
weeks  before  being  placed  in  the  walls. 
They  were  made  hollow,  with  molded 
vertical  grooves  on  the  exposed  surfaces, 
similar  to  ''droved"  stonework,  rebates 
being  made  at  the  top  of  each  block  so 
that  recessed  joints  occurred  at  each 
course  as  it  was  built  into  the  wall. 
After  being  set  in  position  those  blocks 
bearing  concentrated  loads  were  reinforced  with  ^-inch  steel  rods 


Fig.  536.    Wire  Reinforcement  for 
Columns.    American  Steel  and 
Wire  Company. 


Fig.  537.    Concrete  Wall  Column,  Laundry  Building,  Salem,  Mass. 


placed  vertically  inside  the  hollow  spaces  in  the  blocks  and  tied 
together  at  every  third  course  with  ^-inch  steel  wire  ties  in  the 


COLUMNS  AND  PIERS. 


699 


manner  shown.  The  hollow  spaces  were  then  filled  solid  with  a 
grout  of  I  part  of  cement  and  3  parts  of  sand. 

Fig.  538  shows  the  Kahn  trussed  bar  adapted  to  concrete  column 
reinforcement  as  well  as  to  girders,  beams  and  floor  slabs.  It  is 
manufactured  by  the  Trussed  Concrete  Steel  Company,  Detroit, 
Mich.  This  bar  has  been  described  in  Article  582  and  illustrated 
in  Figs.  29,  30,  517  and  518. 

Fig.  539  shows  the  patented  spiral  wire  reinforcement  for  con- 
crete columns  manufactured  by  the  F.  P.  Smith  Wire  and  Iron 
Works,  Chicago,  111.    The  wire  is  cold-drawn  high  or  low  car- 


Fig-  538.    Kahn  Trussed  Bar  Reinforcement. 


bon  wire  with  a  high  elastic  limit  and  tensile  strength  and  is 
continuously  wound  around  and  securely  clinched  to  the  vertical 
reinforcing  bars.  These  bars  are  shown  in  detail  in  Fig.  540, 
which  is  about  one-third  full  size.  These  columns  are  usually 
furnished  with  approximately  2  per  cent  of  vertical  reinforcement. 

Fig.  541  shows  the  unit  column  frame  of  the  Unit  Concrete  Steel 
Company,  Chicago,  111. 

Fig.  542  shows  the  spiral  reinforcing  for -columns  manufactured 
by  the  American  System  of  Reinforcing  for  Concrete  Construction, 
Chicago,  111. 


700 


BUILDING  CONSTRUCTION.  (Ch.  X) 


It  consists  of  varying  sizes  of  wire  ranging  from  No.  7  gauge 
up  to  ^  of  an  inch,  coiled  in  the  form  of  a  heHx,  spaced  from  i 
inch  to  3  inches,  and  in  lengths  as  required.  The  spacing  device 
is  a  heavy  wire,  crimped  to  maintain  the  proper  distance  of  spiral, 
with  a  fiat  piece  of  steel  behind,  securely  bolted  to  the  crimped  wire. 


Fig.    539-     Column    Reinforcement.  Pat- 
ented  Spiral  Wire. 


Fig.  543  shows  the  column  reinforcement  of  the  Monolith  Steel 
Company,  Washington,  D.  C. 

In  this  system  the  Golding  bars  already  described  in  Article  580 
are  used  and  around  them  is  wound  spirally  flat  band  hooping. 
Staples  are  crimped  into  the  groove  on  one  side  of  each  bar  at 
proper  intervals ;  the  necessary  number  of  reinforcing  bars  are 
assembled  on  a  circular  form,  with  the  stapled  sides  outward ;  the 


TYPES  AND  SYSTEMS. 


701 


hooping  is  then  wound  around  them,  so  that  it  passes  between  the 
outwardly  projecting  legs  of  each  staple;  these  are  then  bent  down 
so  as  to  closely  enclose  the.  hooping  and  hold  it  rigidly  in  position 
The  reinforcement  of  the  column  is  thus  assembled  as  a  unit ;  the 
form  made  for  assembling  is  made  to  collapse,  and  the  assembled 
reinforcement  taken  off  and  set  up  in  position. 

Fig.  544  shows  what  is  known  as  the  "T.  I.  M."  Patent  Rein- 


Fig.  543.     The  Golding  Bar 
System  of  Concrete  Col- 
umn Reinforcement. 


forced  Column,  manufactured  by  the  New  York  Fire-proof  Column 
Company,  Hobbken,  N.  J.  These  columns  are  constructed  of  a 
rolled  steel  shell  filled  with  concrete,  in  the  middle  of  which  is  a 
steel  pin. 

5.    TYPES  AND  SYSTEMS  OF  REINFORCED  CONCRETE 
CONSTRUCTION. 

591.  GENERAL  CONSIDERATIONS.— Having  considered 
some  of  the  commonly  used  types  of  reinforcement  in  the  preceding 


702 


BUILDING  CONSTRUCTION.  (Ch.  X) 


subdivision,  some  of  the  types  and  systems  of  reinforced  concrete 
construction  will  be  referred  to,  principally  by  means  of  typical 
illustrations  in  the  figures.  There  are  now  so  many  systems 
and  variations  in  details  that  it  is  impossible  to  even  enumerate 

them  all  here.  The  brief  descriptions 
and  reproductions  of  drawings  of  the 
various  reinforcements  themselves  often 
illustrate  also  the  general  system  used 
throughout  a  building;  and  the  same 
may  be  said  of  the  descriptions  of  the 
various  systems  of  concrete  floor  con- 
struction given  in  Chapter  IX. 

The  various  uses  of  reinforced  con- 
crete are  mentioned  in  Article  525,  and 
the  early  examples  of  the  same  in 
Article  527.  In  Chapter  II  is  discussed 
"concrete  capping  for  wooden  piles"  in 
Article  55  and  "concrete  piles''  in 
Articles  58  to  63.  In  the  same  chapter, 
in  Articles  65  to  71,  the  subject  of 
"reinforced  concrete  footings"  is  treated. 
In  Chapter  III,  in  Articles  99  and  100, 
other  references  are  made  to  "concrete 
footings"  and  to  "building  laws  regard- 
ing concrete  footings." 

The  illustrations  in  the  followinp- 
articles  are  of  various  systems  of  rein- 
forced concrete  construction  as  applied 
to  entire  buildings. 

592.  CLASSIFICATION  OF  TYPES 
AND  SYSTEMS.— Reinforced  concrete 
building  construction,  at  least  that  which  is  used  in  buildings  for 
commercial  purposes,  may  be  broadly  divided  into  two  divisions  or 
types,  (i)  "mill"  construction  in  reinforced  concrete,  and  (2) 
''skeleton"  construction  in  reinforced  concrete ;  and  for  both  of 
these  types  various  systems  of  construction  are  employed. 

593.  MILL  CONSTRUCTION  IN  REINFORCED  CON- 
CRETE.— This  is  similar  in  many  ways  to  the  ordinary  mill  con- 


Fig.  544.  The  T.  I.  M.  Patent 
Reinforced  Column. 


TYPES  AND  SYSTEMS. 


70s 


striiction,*  the  concrete  taking;-  the  place  of  the  beams,  <Tirders,  etc.^ 
of  other  materials.  "In  localities  where  labor  is  high  and  where 
conditions  are  more  or  less  congested,  it  is  probably  more  econom- 
ical to  use  brick  for  walls  than  to  use  concrete.  In  such  cases  the 
type  of  construction  is  similar  to  ordinary  niill  construction.  Pro- 
vision must  be  made  to  anchor  the  beams  and  girders,  which  can  be 
done  by  bending  the  ends  of  the  reinforcing  rods  so  as  to  extend 
horizontally  into  the  wall  each  side."t 

594.  SKELETON  CONSTRUCTION  IN  REINFORCED 
CONCRETE. — This  is  the  type  of  construction  analogous  to  the 
so-called  "skeleton  type"  of  steel  construction.  The  outside  walls 
may  be  of  any  fire-resisting  material,  such  as  brick,  tile,  concrete,, 
etc.,  and  may  or  may  not  cover  also  the  concrete  columns,  piers  and 
girders.  There  is  a  skeleton  framework  of  vertical  supports  and  of 
girders  and  beams  with  floor  systems  of  various  kinds,  and,  as  in 
skeleton  steel  construction,  the  wall  girders  and  columns  carry  part 
of  the  floor  dead  and  live  loads  and  all  of  the  weight  of  the  out- 
side walls. 

When  brick  facing  is  used  to  cover  all  or  part  of  the  outside 
concrete  work,  it  is  usually  secured  in  place  by  means  of  galvanized 
anchors  built  in  the  concrete  as  erected  and  bonding  into  the  joints 
of  the  brick  facing. 

Concrete  panels  or  curtain-wall  panels  are  usually  built  after  the 
wooden  molds  or  forms  are  taken  down  from  the  columns,  girders, 
etc.,  and  are  set,  on  the  sides,  in  vertical  recesses  or  grooves  left 
in  the  sides  of  the  columns  as  the  latter  are  constructed.  These 
panels  are  comparatively  thin,  being  often  6  inches  and  sometimes- 
only  4  inches  in  thickness.  In  place  of  either  brick  or  concrete,, 
hard-burned  fire-proofing  tile  blocks  have  been  used  for  the 
filling-in  panels,  and  sometimes  brick  and  tile  panels  are  covered 
with  stucco. 

595.  AMERICAN  SYSTEM  OF  REINFORCED  CON- 
CRETE CONSTRUCTION.— Fig.  545  shows  the  American  sys-^ 
tem  of  reinforced  concrete  construction  for  short  spans,  used  by  the 
American  Concrete  Steel  Company,  Newark,  N.  J.  Plain  bars  are 
shown,  but  any  other  bars  can  be  used. 

*  See  Chapter  VII  in  "Building  Construction  and  Superintendence,  Part  II,  Car- 
penters' Work,"  and  also  Chapter  XXII  in  the  "Architect's  and  Builder's  Pocket-Book,'* 
both  by  Frank  E.  Kidder.  , 

t  Mr.  Rudolph  P.  Miller  in  Chapter  XXIV  of  the  "Architect's  and  Builder's 
Pocket-Book,  "  by  l^'rank  E.  Kidder. 


704 


BUILDING  CONSTRUCTION,  (Ch.  X)" 


596.  AMERICAN  SYSTEM  OF  REINFORCING  FOR 
CONCRETE  CONSTRUCTION.— Fig.  546  shows  a  general  view 
of  the  system  of  reinforcing  used  by  the  American  System  of 
Reinforcing  for  Concrete  Construction,  Chicago,  111.  The  draw- 
ing shows  the  practical  application  of  rods  and  wire  fabric  to  gir- 
ders, columns  and  floor  slabs,  connections  with  brick  walls,  etc. 
This  system  is  sometimes  called  the  "High  Carbon  System,"  from 
the  nature  of  the  steel  used. 

597.  "  COLUMBIAN  SYSTEM.— Fig.  547  shows  the  general 
construction  of  the  system  used  and  controlled  by  the  Columbian 
Fire-proofing  Company,  Pittsburg,  Pa.  The  Columbian  fire-proof 
-floor  system  was  described  in  Chapter  IX,  Article  445. 


Fig.  545.     Type  Used  by  the  American  Concrete  Steel  Company,  Newark,  N,  J. 


598.  CUMMINGS  SYSTEM.— Fig.  548  shows  the  girder, 
beam  and  column  reinforcement  with  other  details,  the  invention  of 
Mr.  Robert  A.  Cummings.  The  Cummings  loop  truss  frame  was 
discussed  in  Article  585  and  the  Cummings  column  in  Article  590. 
In  the  illustration  at  the  top  of  the  diagram  is  shown  the  Cummings 
method  of  forming  the  bent-up  bars  and  attaching  them  to  the  ten- 
sion bars.  In  general,  the  plan  is  to  provide  tension  bars  with  ends 
specially  anchored,  and  to  securely  attach  to  them  small  hori- 
zontal rods  in  the  mid.dle  of  the  beam  or  girder,  but  bent  up,  as 
indicated,  to  pass  across  the  top  of  the  beam  and  form  inclined 
inverted  U-bars  or  stirrups.    The  idea  is  more  clearly  shown  in  the 


TYPES  AND  SYSTEMS. 


705 


sketches  below  showing  the 
''arrangement  of  steel."  The 
''supporting  chairs/'  placed  at 
the  point  of  the  bending  up  of 
the  rods,  are  also  drawn.  For 
the  slab  steel  another  type  of 
supporting  chair  is  employed, 
as  illustrated  in  the  detail 
sketch. 

The  Cummings  hooped  col- 
umn is  also  shown  in  the  upper 
sketch  and  the  detail  of  the 
column  reinforcement  below. 
Each  hoop  is  securely  attached 
to  the  upright  rods. 

599.  CORRUGATED  OR 
JOHNSON  BAR  REIN- 
FORCING SYSTEM.  — Fig. 
549  shows  one  of  the  types  of 
construction  used  by  the  Ex- 
panded Metal  and  Corrugated 
Bar  Company,  St.  Louis,  Mo. 
The  drawing  shows  a  typical 
floor  bay  in  perspective  and  in 
section,  with  the  method  of 
constructing  and  reinforcing 
the  columns,  girders,  beams 
and  floor  slabs  of  an  all-con- 
crete building.  The  type  of 
construction  shown  is  suitable 
for  spans  of  more  than  14  feet. 
There  are  several  other  types 
of  this  particular  system  suited 
to  various  widths  of  spans, 
methods  of  framing,  etc.  (See 
also  Article  575.) 

Fig.  551  shows  another  sys- 
tem, that  of  a  steel  frame  with 
floors   of   concrete  reinforced 


o6 


BUILDING  CONSTRUCTION. 


(Ch.  X> 


TYPES  AND  SYSTEMS. 


707 


with  the  Johnson  corrugated  bars  and  used  in  connection  with 
hollow  tiles  as  shown.  The  upper  drawing  of  the  figure  shows  the 
longitudinal  section  through  a  beam  and  the  lower  drawing  a  trans- 
verse section.  (See  also  the  Kahn  Hollow  Tile  and  Concrete  Con- 
struction, Article  605,  Fig.  557.) 

600.  EXPANDED  METAL  AND  ROUND  BAR  SYSTEM. 
EXAMPLE. — Fig.  550  shows  an  example  of  this  construction,  in 


Fig.  549.     Corrugated  or  Jolmson  Bar  Reinforcing  System. 


a  cross-section  drawing  of  the  Lynn  Storage  Warehouse,  Lynn, 
Mass.*  Fig.  552  shows  details  of  typical  girder,  beam  and  column. 
Round  bars  or  rods  are  used  for  the  reinforcement  of  the  girders, 
beams  and  columns,  while  expanded  metal  forms  the  slab  reinforce- 
ment. 

601.  FABER  SYSTEM  OF  TILE  AND  CONCRETE  CON- 
STRUCTION.— Fig.  553  shows  a  system  of  construction  quite 
similar  to  that  illustrated  in  Article  599,  Fig.  551,  and  in  Articles  602, 

*  Mr.  D.  A.  Sanborn,  Lynn,  Mass.,  architect;  Mr.  J.  R.  Worcester,  consulting 
engineer;  Eastern  Expanded  Metal  Company,  Boston,  Mass.,  designers  of  the  reinforced 
concrete  and  contractors  for  the  building.  Drawings  reproduced  through  the  courtesy  of 
the  Atlas  Portland  Cement  Company,  New  York. 


7o8  BUILDING  CONSTRUCTION.  (Ch.  X) 


rig.   550.     Cross-section  Through  Reinforced  Storage  Warehouse,  Lynn,  Mass. 


TYPES  AND  SYSTEMS. 


709 


604,  etc.  This  system  has  been  extensively  used  in  Europe  and 
was  introduced  into  the  United  States  by  the  Faber  Construction 
Company,  New  York,  which  holds  the  patents.  Unlike  some  of  the 
other  concrete-and-tile  systems,  however,  this  construction  rein- 
forces the  floors  longitudinally  and  transversely,  so  that  the  slabs 


LONGITUOINAL  SCCTiON    TH^O  B£AM 


I'ig.  55 Combined  I-beam,  Hollow  Tile  and  Reinforced  Concrete  System. 

have  their  strength  determined  as  if  they  were  supported  on 
four  sides.  The  concrete,  which  is  a  rich  mixture  of  i  to  3 
Portland  cement  and  sand,  is  kept  out  of  the  tile  hollows  by  the 
tubes  of  cardboard  used  as  shown ;  and  in  figuring  compressive 


Typical  Dctail  o'  Columi}^ 

Fig.  552.     Beam,  Girder  and  Column  Details,  Storage  Warehouse,  Lynn,  Mass. 


resistance  the  tiles  are  assumed  to  assist  in  it,  as  they  are  made 
heavier  than  those  for  ordinary  use. 

602.  THE  GABRIEL  SYSTEM  OF  REINFORCED  CON- 
CRETE CONSTRUCTION.— Fig.  554  shows  sections  of  girders, 
beams,  columns  and  floor  slabs  for  heavy  construction  used  by  the 


710 


BUILDING  CONSTRUCTION.  (Ch.  X) 


Gabriel  Concrete  Reinforcement  Company,  Detroit,  Mich.,  the 
details  being  taken  from  drawings  of  the  W.  H.  Edgar  &  Sons 
Company's  sugar  warehouse,  Detroit,  Mich.*  This  is  another 
example  of  a  combined  tile  and  reinforced  concrete  floor  slab  con- 
struction. 

603.  HENNEBIQUE  SYSTEM.— Fig.  555  shows  a  general 
view  of  this  construction,  already  illustrated  in  detail  in  regard 
to  girder  and  column  reinforcement  in  Article  581,  Fig.  516,  and 
in  Article  590,  Fig.  531. 

604.  KAHN  BAR  COMBINED  WITH  PLAIN  ROD  CON- 


Fig.   553.     Faber  System  of  Tile  and  Concrete  Construction. 


STRUCTION. — Fig.  556  shows  sections  through  a  portion  of  the 
building  erected  by  the  Lord  Baltimore  Press,  Baltimore,  Md.f 
The  steel  reinforcement  consists  of  plain  round  rods  for  the  walls, 
columns,  floor  slabs  and  roof  slabs  and  of  Kahn  truss  bars  for 
beams  and  girders. 

605.  KAHN  HOLLOW  TILE  AND  REINFORCED  CON- 
CRETE SYSTEM.— Fig.  557  shows  the  Kahn  hollow  tile  and 

*  Stratton  &  Baldwin,  architects,  Detroit,  Mich. 

+  Ballinger  &  Perrot,  architects,  Philadelphia,  Fa.  Courtesy  of  the  architects  and 
William  T.  Comstock,  publisher.  See  Architect's  and  Builder's  Magazine,  January,  1908^ 
for  description  of  building. 


TYPES  AND  SYSTEMS. 


yii 


TYPES  AXD  SYSTEMS. 


713 


concrete  system  of  construction  similar  to  that  illustrated  in  Articles 
599,  601  and  602.    (See  also  Article  582  and  Fig-.  538.) 

Like  other  similar  systems,  this  consists  of  a  number  of  reinforced 
concrete  beams  separated  by  spaces,  into  which  the  tiles  fit.  The 
common  form  of  centering  consists  of  planks,  a  little  wider  than  the 
concrete  beams,  set  where  the  beams  are  to  come  above.  The  tiles 
are  placed  in  rows  with  their  side  edges  resting  on  the  planks  and 
form  the  sides  of  the  concrete  beam  molds.  After  the  reinforce- 
ment is  put  in  position  the  concrete  is  poured  in,  care  being  used 
to  avoid  pushing  the  tiles  out  of  place.  The  latter  are  laid  together 
with  as  close-fitting  end  joints  as  possible.  Lath  is  unnecessary  for 
the  ceiling,  as  it  is  flat  and  ready  for  plaster ;  and  the  construction 


Fig.  557.     Kahn  Tile  and  Concrete  Construction. 


when  used  in  roofs  diminishes  the  amount  of  condensation  on  the 
under  surfaces. 

606.  MERRICK  SYSTEM.— This  system  of  reinforced  con- 
crete .construction,  controlled  by  Mr.  Ernest  Merrick,  New  York, 
has  already  been  described  in  Chapter  IX  and  illustrated  in  Figs. 
386  and  387. 

607.  MUSHROOM  SYSTEM.— Fig.  558*  shows  the  so-called 
''Mushroom  System,"  the  invention  of  Mr.  C.  A.  P.  Turner  of 
Minneapolis,  Minn.  This  is  a  flat  slab  construction,  the  rods  run- 
ning between  the  columns  both  transversely  and  diagonally,  as  shown 
in  the  figure.  The  construction  results  in  a  large  column  capping. 
The  idea  is  to  do  away  with  all  girders  and  beams  and  to  support 
the  floor  slabs  directly  by  the  walls  and  columns. 

608.  SYSTEM  ^'M."    Fig.  559  shows  a  system  of  reinforced 


*  Courtesy  of  the  Atlas  Portland  Cement  Company,   New  York. 


14  BUILDIXG  CONSTRUCTION.  (Ch.  X) 


concrete  construction  introduced  by  the  Standard  Concrete  Com- 
pany of  New  York,  and  known  as  "System  M." 

In  this  system  reinforced  concrete  floor  construction  is  adapted 
to  the  ordinary  fire-proof  city  building,  where  rapidity  in  erection  is 
required  and  where  the  necessary  space  for  storing  materials  about 
the  building  site  cannot  be  had.  In  this  "System  M"  a  light  steel 
skeleton  is  erected  and  the  concrete  work  added  in  the  same  manner 
as  for  fire-proofing  work. 


Fig.  558.    Mushroom  System  of  Reinforced  Concrete  Construction. 


The  light  steel  frame  gives  a^rigid  working  floor  and  materially 
assists  in  the  erection  of  the  reinforcing  work. 

The  erection  of  the  building  proceeds  as  rapidly  as  does  the 
erection  of  all  steel  and  fire-proof  construction. 

In  this  form  of  construction  the  light  framework  is  inclosed  in 
the  concrete  in  such  a  manner  that  the  floor  members  take  care  of 
all  vertical  shear  and  finally  become  tension  members  to  the  rein- 
forced concrete  floors. 

Where  necessary,  steel  web  members  are  introduced  so  that  the 
web  stresses  are  positively  transmitted  to  the  chord  members. 

The  columns  are  designed  for  gross  loads  and  the  rest  of  the 


TYPES  AND  SYSTEMS. 


7^S 


members  of  the  steel  skeleton  designed  to  carry  the  dead  loads  of 
the  structure. 

One  objection  to  this  construction  is  that  the  metal  shapes  which 
have  to  be  used  to  obtain  the  necessary  strength  do  not  give  a  total 
adhesive  resistance  proportional  to  the  total  amount  of  metal.  Steel 
used  in  this  way,  therefore,  is  not  economical.  Another  objection 
is  that  there  is  some  flexure  in  the  metal  shapes  used,  which  tends 
to  disturb  the  steel  and  concrete  bond. 

609.  COMPOSITE  CONCRETE  AND  STRUCTURAL 
STEEL  SYSTEMS.— Fig.  560*  shows  a  system  of  construction 


Fig.  559.    System  "M."    Standard  Concrete  Steel  Company. 


in  which  composite  columns,  combinations  of  concrete  and  struc- 
tural steel  are  used  in  connection  with  reinforced  concrete  girders, 
beams  and  floor  slabs. 

The  following  is  a  brief  description  of  the  principal  features  of 
the  system  used  in  this  building: 

"One  of  the  problems  in  concrete  building  construction,  where  the  loads  are 
heavy  or  the  building  is  several  stories  high,  is  to  build  the  columns  small 
enough  to  satisfy  the  requirements  of  the  occupants  and  owners  without  over- 
loading the  concrete.  Its  solution  is  especially  difficult  in  a  city  building 
where  the  land  area  is  so  valuable  that  every  square  inch  of  floor-space  is  at 
a  premium  and  where  there  must  be  more  stories  than  are  economical  under 
■other  conditions.    Moreover,  the  building  laws  of  many  cities  require  more 

*  The  section  shown  is  from  the  drawing  of  the  design  for  the  plant  of  the  Ketter- 
linus  Lithographical  Manufacturing  Company,  Philadelphia,  Pa.,  Ballmper  &  ^^^^9}' 
architects  and  engineers,  Philadelphia,  Pa.  The  drawing  is  reproduced  through  the 
courtesy  of  the  architects  and  of  the  Atlas  Portland  Cement  Company,  New  \ork. 


7i6 


BUILDING  CONSTRUCTION. 


(Ch.  X> 


conservative  loading  than  might  be  warranted  if  it  were  certain  that  the  con- 
ditions of  construction  were  in  all  cases  the  best. 

"In  a  number  of  recent  instances  the  difficulty  has  been  met  by  the  use  of 
composite  columns,  a  combination  of  concrete  and  structural  steel,  and  this 
is  the  plan  followed  by  the  designers  of  the  Ketterlinus  building.  Full  details 
of  the  column  construction  are  presented  in  Fig.  560. 


rBETAIL***''*UMT^  GlPBElR.*  FrAME"*  CoN STRUCTDOT^ 

■WmriHl    STAR    SlhiAPED)  STEEL   KEIN FOTCCEMEH T   IN  COLUMN 


Fig.  560.    Section  Through  a  Bay  of  Ketterlinus  Building,  Philadelphia,  Pa. 

"The  interior  columns  in  the  building  up  to  the  fifth  floor  are  23  inches  in 
diameter.  In  the  basement  and  the  four  lower  stories  the  core  of  the  column 
is  formed  of  steel  plates  and  angle-irons  rivetted  together  in*  the  form  of  a 
cross.  Around  this  cross  >^-inch  wire  ties  were  placed  every  12  inches  and 
looped  around  four  vertical  round  rods  which  increased  the  reinforcement. 
In  the  basement,  for  example,  the  center  steel  is  made  up  of  a  plate  l8' 
inches  wide  and  %  of  an  inch  thick  with  two  plates  of  similar  thickness,  but 


TYPES  AND  SYSTEMS. 


7^7 


of  8-inch  width  at  right-angles  to  it,  and  four  angle-irons  6  by  6  by  ^  of  an 
inch,  all  rivetted  together.  The  four  round  rods  which  complete  the  so-called 
"Star"  reinforcement  are        inches  in  diameter. 

"The  columns  in  the  three  stories  nearest  the  top  are  designed  to  carry  the 
full  dead  and  live  loads  of  floors  and  roof.  In  each  lower  story  the  columns 
are  designed  to  carry  the  full  dead  load  and  a  smaller  proportion  of  the  full 
live  load  than  can  be  carried  by  the  floor  construction,  this  live  load  factor 
being  reduced  proportionately  to  the  number  of  floors  carried.  For  example, 
the  basement  columns  were  calculated  on  a  basis  of  carrying,  on  the  steel 
ceres  alone,  three-fourths  of  the  live  load  plus  the  full  dead  load,  with  a 
factor  of  safety  of  4. 

"The  steel  is  designed  to  bear  the  computed  load  without  exceeding  a  maxi- 
mum compression  of  16,000  pounds  per  square  inch.  The  compressive  strength 
of  the  concrete  in  these  columns  is  not  considered,  although  it  is  almost 
sufficient  to  carry  the  dead  load. 

"The  weight  of  the  girders  is  borne  in  part  by  brackets  of  steel  rivetted  to 
the  angle-irons  and  partly  by  the  concrete  knees  or  enlargements  of  the 
column  which  run  out  obliquely  from  the  columns  and  which  are  reinforced 
on  each  side  by  two  ^-inch  rods. 

"Above  the  fourth  story  the  columns  are  of  the  same  diameter,  but  with  the 
more  ordinary  reinforcement  of  four  round  rods. 

"To  transmit  the  compressive  load  from  the  steel  in  the  columns  to  the  soil,, 
a  special  design  of  footing  was  prepared.  A  large  base  was  necessary  to 
prevent  too  great  loading  of  the  soil  beneath  the  building,  and  in  order  that 
the  pressure  from  the  column  might  not  break  or  crush  the  concrete  over  this 
large  area,  a  grillage  of  steel  I-beams  was  placed  under  each  column,  as  shown 
in  the  figure,  and  the  concrete  below  these  I-beams  further  strengthened 
against  breakage  and  shear  by  i-inch  horizontal  round  rods  placed  6  inches, 
apart,  and  by  ^  by  i  inch  stirrups. 

"Each  girder  was  designed  as  an  independent  beam  supported  at  the  ends, 
by  the  enlargement  of  the  columns  and  the  steel  brackets.  The  area  of  the 
reinforcing  steel  was  calculated  in  the  usual  way ;  but  instead  of  placing  each 
rod  separately  in  the  form,  girder  frames  were  made  from  quadruple  or  twin- 
webbed  bars,  which  were  cut,  bent  to  shape  and  furnished  with  stirrups 
fastened  to  them  in  the  shop.  The  girder  frame  Reinforcement  was  brought  to 
the  building  in  the  form  of  a  truss,  and  the  work  of  placing  consisted  simply  of 
setting  this  truss  in  the  form  upon  cast-steel  sockets,  each  having  a  ^-inch 
threaded  stud  projecting  upward  through  the  frame.  A  nut  screwed  down 
on  this  stud  over  the  frame  holds  it  rigidly  in  position.  This  girder  frame 
and  socket  were  the  invention  of  Mr.  Emile  G.  Perrot,  one  of  the  firm  of 
architects  who  designed  the  building,  the  object  being  to  insure  the  exact 
amount  and  arrangement  of  tension  and  shear  members  in  the  exact  loca- 
tion as  designed,  and  to  afford  opportunity  for  inspection  of  the  steel  in 
position  before  the  pouring  of  the  concrete. 

"The  rods  are  rolled  in  sets  of  four,  connected  by  a  web,  and  this  web 
\z  sheared  and  bent  down  in  2-inch  lengths  at  intervals  of  3  inches,  to  give 


7i8 


BUILDING  CONSTRUCTION. 


(Ch.  X> 


:greater  grip  in  tlic  concrete.  These  2-inch  lengths  are  bent  back  over  stirrups, 
where  they  occur,  to  cHnch  them  in  position  on  the  fram:e.  The  outside  bars 
are  also  cut  loose  at  each  end  and  bent  upward  to  reinforce  the  top  of  the 
beam  near  the  supports.  The  sockets  shown  in  the  figure  are  shaped  so 
that  they  support  the  rods  lYz  inches  above  the  bottom  of  the  beam  or 
girder,  and  are  held  in  place  by  a  ^-inch  bolt  passing  up  through  the  bottom 
•of  the  wood  mold.  These  threaded  sockets  afterward  are  ttsed  for  securing 
ishafting,  hangers  or  other  fixtures. 

"The  floor  slabs  are  of  usual  construction,  being  4  inches,  thick  and  rein- 
forced for  the  net  span  of  3  feet  10  inches  with  3-inch  No.  10  expanded- 
metal,  this  mesh  having  been  substituted  in  place  of  ^-inch  rods  spaced  6 
inches  apart  and  of  occasional  ^-inch  rods  running  in  the  other  direction,  as 
originally  shown  on  the  drawings,  and  at  an  increase  of  about  i  per  cent 
of  the  cost  of  the  building. 

'The  wearing  surface  in  a  1 54-inch  maple  floor  on  2  by  4-inch  sleepers  16 
inches  apart.  These  arc  placed  on  the  concrete  slabs  and  cinder  concrete  in 
proportions  of  i,  3  and  7  filled  in  between  them. 


Copper  /vcf//^t/e. 

cement  /r7ortc7r- 


Fig.  561.     Brick  Facing  for  Concrete  Wall.  Ket- 
terlinus  Building,   Philadelphia,  Pa. 


"The  walls  are  essentially  reinforced  concrete  columns,  veneered  on  the 
outside  with  4  inches  of  brickwork  and  separating  the  windows.  The  win- 
dow lintels  are  of  concrete  faced  with  terra-cotta  to  match  the  red  sandstone 
of  the  older  building  adjoining  and  are  anchored  to  the  concrete.  The  lintels 
form  reinforced  concrete  beams  and  support  a  brick  wall  13  inches  thick, 
which  is  run  up  to  the  bottom  of  the  terra-cotta  window  sills. 

"The  method  of  connd^ting  the  brick  with  the  concrete  of  the  columns  is 
shown  in  Fig.  561,  copper  wall-ties  1-16  by  ^  by  7  inches  being  set  in  the 
concrete  at  intervals,  and,  after  the  removal  of  the  forms,  bent  out  and  laid 
into  the  joints  of  the  face-bricks,  which  are  separated  from  the  concrete  by  a 
^-inch  mortar  joint  for  purposes  of  alignment." 

The  reinforced  concrete  stairs  for  this  building  were  mentioned 
in  Article  489,  and  illustrated  in  Fig.  451  in  Chapter  IX. 

Fig.  562*  shows  another  example  of  a  metal  core  column  de- 
signed for  tall  or  heavily  loaded  buildings,  the  steel  skeleton  being 
incased  in  the  concrete  and  having  the  necessary  strength  to  bear 


*  The  figure  shows  a  perspective  view  of  one  of  the  lattice  columns  with  connec- 
tions for  reinforced  concrete  girders,  designed  by  Professor  William  H.  Burr  for  the 
McGraw  building.   New   York  City. 


TYPES  AND  SYSTEMS. 


719 


the  entire  load  or  the  greater  part  of  it  and  resulting  in  a  relatively 
small  total  cross-section  desirable  for  the  purpose  of  economizing 
floor  space.  The  incasing  concrete  is  used  merely  as  a  protection 
from  fire  and  corrosion,  and  not  included  in  the  calculations  for  the 
strength  of  the  column,  which  is  designed  to  bear  the  entire  dead 
load,  but  not  to  be  stressed  for  this  load  more  than  is  allowed 


Fig.  562.    Metal  Core  Column,  [NIcGraw  Building,  New  York  City. 


for  Steel  columns  by  the  New  York  building  laws,  taking  into  con- 
sideration the  ratio  of  length  to  the  radius  of  gyration. 

In  the  case  of  this  building  the  compressive  stresses  for  dead 
loads  were  not  allowed  to  exceed  9,000  pounds  per  square  inch.  By 
using  such  an  amount  of  concrete  inside  of  the  steel  column  frame- 
work that  750  pounds  per  square  inch,  or  one-twelfth  of  9,000 


720 


BUILDING  COXSTRUCTIOiW 


(Ch.  X) 


TYPES  AND  SYSTEMS. 


721 


pounds  per  square  inch,  is  the  maximum  stress  on  the  concrete,  the 
live  loads  are  provided  for. 

610.  VISINTINI  SYSTEM.— Fig.  563=^=  shows  the  details  of 
girders  and  floor  beams  of  the  system  invented  by  Franz  Visintini, 
an  architect  of  Zurich,  Switzerland.  Although  applied  in  a  number 
of  cases  in  Europe,  it  was  not  introduced  into  the  United  States 
until  1904,  when  it  was  used  in  the  factory  building  erected  at 
Reading,  Pa.,  for  the  Textile  Machine  Works,  by  the  Concrete 
Steel  Engineering  Company,  New  York,  which  controls  the  Ameri- 
can patents. 

Running  across  the  building  from  column  to  column  and  12^2 
feet  apart  on  centers  are  the  large  Visintini  lattice  girders  24  feet 
long. 

In  ordinary  design  these  would  be  connected  by  floor  beams 
spaced  6  or  8  feet  apart,  with  slabs  between  the  beams.  The  Visin- 
tini system,  however,  permits  the  slabs  and  floor  beams  to  be  laid 
as  one ;  that  is,  after  placing  the  girders,  the  floor  beams  are  laid 
from  girder  to  girder,  but  close  together  so  as  to  form  a  floor 
slab  of  themselves. 

The  details  of  a  typical  floor  girder,  roof  girder  and  floor  beam 
are  shown  in  Fig.  563.  The  girders  have  their  members  arranged 
like  those  of  a  Pratt  truss,  a  common  type  used  in  steel  bridges ; 
and  the  computations  of  stresses  are  made  as  in  bridge  design. 
The  bottom  chord  consists  of  a  slab  of  concrete  reinforced  with 
3  round  rods  to  take  all  of  the  tension,  and  the  top  chord  in  com- 
pression is  similarly  reinforced.  The  vertical  web  members,  which 
are  in  compression,  are  of  plain  concrete,  while  the  diagonals  are 
each  reinforced  for  tension  with  rods  whose  ends  are  attached  to 
the  rods  of  the  top  and  bottom  chords. 

The  floor  beams  are  only  6  inches  thick  and  12  feet  5  inches  long; 
and  these,  as  stated  above,  form  the  slab  also,  being  placed  close 
together.  The  girders  are  designed  and  computed  as  Warren 
trusses  with  all  of  the  web  members  inclined  45°,  half  of  them  in 
tension  and  half  in  compression. 

One  of  the  chief  advantages  of  this  type  of  construction  is  in  the 
method  of  molding  the  beams  and  girders  so  as  to  reduce  the  cost 
of  the  forms.    In  this  particular  case  the  work  was  greatly  facil- 

*  Courtesy  of  the  Atlas  Portland  Cement  Company,  New  York. 


BUILDING  CONSTRUCTION.  (Cii.  X) 


itated  because  the  building  was  erected  in  winter.  The  beams,  of 
which  there  are  about  2,900,  were  molded  on  the  ground  in  an 
adjacent  building.  The  proportions  for  the  beam  concrete,  based 
on  cement  loosely  measured,  were  one  part  of  Portland  cement  to 
one  part  of  sand  to  three  parts  of  stone  screenings.  The  floor 
beams  weigh    only  480  pounds  each. 

The  cores,  which  were  oiled  before  placing,  were  pulled  a  few 
hours  after  the  pouring,  and  the  side  and  bottom  forms  were  left  on 
for  two  days,  when  the  beams  were  hard  enough  to  move.  After 
setting  from  10  to  30  days  longer,  as  needed,  they  were  carried  to 
the  building  and  raised  in  place.  They  were  run  on  to  the  first 
floor  of  the  building,  and  then  raised  by  a  platform  elevator  through 
an  open  bay  to  the  floor  where  they  were  required. 

Two  of  the  floor  beams  were  tested  to  destruction  and  broke 
under  a  load  of  pig-iron  weighing  342  pounds  per  square  foot. 
The  building  is  designed  for  a  safe  working  load  of  75  pounds  per 
square  foot. 

The  girders  weigh  about  three  tons  each,  and  were  molded  upon 
the  floor  immediately  underneath  their  final  position ;  so  that  they 
required  only  to  be  hoisted  into  place,  a  distance  of  14  feet.  This 
was  done  by  means  of  a  special  derrick  and  two  strong  hoists. 

The  proportions  were:  one  part  of  Po-rtland  cement  (measured 
loosely),  parts  of  sand  and  3^  parts  of  broken  trap  rock 

passing  through  a  i^-inch  ring. 

To  tie  the  columns  together  across  the  building,  the  floor  beams, 
were  placed  with  a  5-inch  opening  between  their  ends,  and  this 
space  was  filled  with  concrete  in  which  was  imbedded  a  rod,  as 
shown,  just  above  the  cross-section  of  the  girder  in  the  lower 
drawing  of  the  figure. 

6.    PROTECTION  OF  REINFORCED  CONCRETE  CON- 
STRUCTION. 

611.  GENERAL  CONSIDERATIONS.— The  protection  of 
reinforced  concrete  construction  includes  protection  against  fire 
and  protection  against  corrosion. 

612.  PROTECTION  AGAINST  FIRE.— The  fire-resisting 
properties  of  concretes  in  general  were  discussed  in  Chapter  IX, 
under  ''Fire-proofing  Materials,"  and  in  this  chapter  in  Article  507; 
and  the  kinds  of  concrete  used  in  reinforced  work  in  Article  558. 


PROTECTION, 


The  concretes  considered  in  reinforced  concrete  work  in  questions 
of  fire-resistance  are  the  stone  and  gravel  concretes,  as  cinder 
concrete,  although  very  useful  when  fire-proofing  is  the  primary 
consideration,  is  unreliable  in  regard  to  strength. 

The  principal  considerations  involved  in  the  fire-proof  character 
of  concrete  are  non-conductivity  and  loss  of  strength. 

Several  series  of  tests  have  been  made  to  determine  the  conduc- 
tivity of  various  concretes  subjected  to  different  temperatures. 
Among  others  the  reader  is  referred  to  some  tests*  recently  made 
by  Professor  Woolson  of  Columbia  University,  New  York  City. 

From  2  to  2^  inches  of  concrete  covering  will  protect  rein- 
forcing metal  from  injurious  heat  for  the  period  of  any  ordinary 
conflagration,  provided  that  the  concrete  stays  in  place  during  the 
fire  and  that  the  reinforcing  metal  exposed  to  the  fire  does  not 
convey  by  conductivity  an  injurious  amount  of  heat  to  the  imbedded 
portion.  Gravel  concrete  in  reinforced  work  is  not  considered  a 
safe  or  reliable  fire-resisting  aggregate. 

In  regard  to  loss  of  strength,  it  has  been  found  that  all  concrete 
mixtures  when  heated  throughout  to  a  temperature  of  from  1,000° 
to  1,500°  Fahr.  lose  a  large  proportion  of  their  strength  and 
elasticity ;  and  this  fact  must  be  borne  in  mind  in  designing. 

Tests  have  been  made  to  determine  the  effects  of  extreme  heat 
upon  concretes,  and  the  reader  is  referred  to  an  excellent  summaryf 
of  the  results  obtained  and  reported  by  Professor  Woolson  of' 
Columbia  University,  New  York  City. 

Recent  tests  made  by  city  authorities,  notably  those  of  New 
York  and  Philadelphia,  and  the  great  conflagrations  in  Baltimore 
and  San  Francisco,  have  afforded  opportunities  for  observing  the 
effect  of  fire  on  reinforced  concrete  construction  of  various  kinds. 

The  artificial  tests  show  that  ''to  a  depth  averaging  about  one  inch 
the  concrete  is  seriously  impaired  and  is  easily  washed  off  by  a 
hose  stream  applied  to  the  surface.  Any  stone  containing  an  appre- 
ciable percentage  of  carbonate  of  lime  will  calcine  and  cause  fail- 
ure. Where  the  construction  is  poorly  designed,  allowing  an 
excessive  deflection,  the  fine  cracks  in  the  concrete  below  the  steel 

*  See  Engineering  Neivs,  August  15,  igoy,  p.  168,  and  the  "Architect's  and  Builder's 
Pocket-Bcok,"  Frank  E.  Kidder.  Chapter  XXIV. 

t  See  Proc.  Am.   Soc.  Testing  Materials.   \'ol.  pp.  443,  446  and  448.     See  also 

Tables  VIII  and  IX,  Chapter  XXIV,  the  "Architect's  and  Builder's  Pocket-Book,"  Frank 
E.  Kidder. 


724 


BUILDING  CONSTRUCTION.  (Ch.  X) 


will  open  to  such  an  extent  as  to  allow  the  heat  to  reach  the  metal 
reinforcements.  When  the  reinforcement  is  such  as  to  produce 
a  plane  of  weakness  in  the  concrete  there  is  liable  to  be  a  flaking 
off  of  concrete  and  a  consequent  exposure  of  metal."* 

A  report  of  a  committee  of  engineers,  investigating  the  effects 
of  great  heat  on  concrete  construction  in  the  fire  following  the 
San  Francisco  earthquake  in  1906,  gives  the  following  summary: 

"Concrete  floors  generally  had  hung  ceilings,  and,  where  thus 
'  protected,  were  uninjured.  Where  exposed,  the  concrete  is  in  most 
cases  destroyed,  as,  for  instance,  in  the  Sloan,  Rialto  and  Aronson 
buildings  and  in  the  Crocker  warehouse.  The  concrete  is  dry,  and 
while  in  many  cases  hard,  yet  all  the  water  has  been  burned  out 
and  it  may  be  said  to  be  destroyed,  even  if  able  to  support  weights. 
Floor  coverings  of  wood  invariably  burned,  adding  to  the  destruc- 
tion. Sleepers  were  generally  burned.  Surfaces  of  cement  mortar 
fared  much  better,  the  linoleum  covering  remaining  practically 
intact."  t 

Mr.  A.  L.  A.  Himmehvright  concluded,  after  an  examination  of 
the  ruins  of  the  buildings  in  San  Francisco,  that,  as  a  fire-resisting 
construction,  reinforced  concrete  is  inferior  to  any  type  of  steel 
construction  with  concrete  floors  and  concrete  column  and  girder 
protection,  but  superior  to  steel  construction  with  terra-cotta  floor 
and  terra-cotta  column  and  girder  protection.  He  states  that 
''where  this  method  was  used  a  very  slight  attack  of  fire  was  gen- 
erally sufiicient  to  cause  the  rupture  of  the  concrete  underneath 
the  reinforcing  metal,  so  that  it  fell  away,  exposing  the  metal. 
There  were  comparatively  few  buildings,  however,  in  which  this 
method  of  construction  was  used.":|: 

In  regard  to  the  thickness  of  concrete  required,  "from  a  study 
of  the  tests  and  fires  above  referred  to,  a  fair  conclusion  as  to  the 
amount  of  protection  against  fire  would  seem  to  be :  In  all  columns, 
in  large  and  important  girders,  trusses  or  other  supports,  at  least 
two  inches  of  concrete  outside  of  all  reinforcement;  in  girders  and 
beams  and  slabs  of  long  spans,  about  one  and  one-half  inches  of 
concrete  outside  of  all  reinforcement ;  in  stair  work,  floor  slabs 

*  See  also  resume  of  results  of  and  conclusions  from  tests  and  conflagrations  by  Mr. 
Rudolph  P.  Miller  in  Chapter  XXIV,  the  "Architect's  and  Builder's  Pocket-Book,"  by 
Frank  E.  Kidder. 

t  Proc.  Am.  Soc.  C.  E.,  March,   1907,  p.  330. 

X  Proc.  Am.  Soc.  C.  E.,  August,  1907.  p.  668. 


PROTECTION. 


7^S 


(short  span),  walls  and  partitions,  from  three-quarters  to  one  inch 
of  concrete  outside  of  all  reinforcement. 

''In  footings  and  foundations  the  thickness  of  concrete  outside 
of  reinforcement  should  be  at  least  three  inches.  Not  for  fire  pro- 
tection, but  for  protection  against  corrosion."''' 

613.    PROTECTION     AGAINST     CORROSION.— Experi- 
ments have  been  made  to  determine  the  extent  of  the  corrosion 
of  reinforcing  metals  in  reinforced  concrete  of  different  kinds  and 
«  mixtures,  and  much  has  been  recently  written  on  the  subject. 

Professor  Charles  L.  Norton,  of  the  Massachusetts  Institute  of 
Technology,  Boston,  Mass.,  draws  the  following  conclusions  as 
the  result  of  experiments  and  tests  made  during  the  years  1902  and 
1903 :t 

In  these  experiments  the  steel  was  encased  in  concrete  one  and 
one-half  inches  thick  on  all  sides. 

(1)  Steel  imbedded  in  neat  cement  is  secure  against  corrosion. 

(2)  Steel  imbedded  in  a  dense  concrete  mixture  is  safe  against 
corrosion. 

(3)  To  assure  a  thorough  coating  of  the  steel  the  concrete  should 
be  mixed  wet. 

(4)  Porous  concrete,  allowing  the  admission  of  moisture,  will 
not  protect  the  steel  thoroughly. 

(5)  A  coating  of  rust  is  not  a  protection  against  further  corro- 
sion, as  has  been  sometimes  claimed. 

From  these  conclusions  it  would  appear  that  the  steel  of  rein- 
forced concrete  is  secure  against  corrosion,  provided  that  it  is 
thoroughly  imbedded  in  concrete  and  that  a  slight  coating  of  rust 
on  the  steel,  where  imbedded,  does  no  harm,  as  the  cement  is 
strongly  alkaline,  counteracts  the  acidity  of  the  iron  oxide  and 
prevents  further  corrosion. 

On  the  question  of  the  corrosion  of  steel  in  cinder  concrete, 
Professor  Norton  concludes :  ''There  is  one  limitation  to  the  whole 
question,  that  is,  the  possibility  of  getting  the  steel  properly  incased 
in  concrete.  Many  engineers  will  have  nothing  to  do  with  con- 
crete because  of  the  difficulty  in  getting  'sound'  work.  '  This  is 
especially  true  of  cinder  concrete,  where  the  porous  nature  of  the 

*  Mr.  Rudolph  P.  Miller,  in  Chapter  XXIV,  of  the  "Architect's  and  Builder's  Pocket- 
Book,"  by  Frank  E.  Kidder. 

t  See  Reports  Nos.  4  and  9,  Insurance  Experiment  Station,  r>oston  Manufacturers' 
Mutual  Fire  Insurance  Company. 


726  BUILDING  CONSTRUCTION.  (Ch.  X) 

cinders  has  led  to  much  dry  concrete,  many  voids  and  much 
corrosion.  I  feel  that  nothing  in  this  whole  subject  has  been  more 
misunderstood  than  the  action  of  cinder  concrete.  We  usually  hear 
that  it  contains  much  sulphur  and  that  this  causes  corrosion. 
Sulphur  might  cause  corrosion,  if  present,  were  it  not  for  the 
presence  of  the  strongly  alkaline  cement ;  but  with  the  latter  present 
the  corrosion  of  steel  by  the  sulphur  of  cinders  in  a  sound  Port- 
land cement  concrete  is  the  veriest  myth  ;  and,  as  a  matter  of  fact, 
the  ordinary  cinders,  classed  as  steam  cinders,  contain  only  a  very 
small  amount  of  sulphur.  There  can  be  no  question  that  cinder 
concrete  has  rusted  great  quantities  of  steel ;  not  because  of  its 
sulphur,  but  because  it  was  mixed  too  dry,  through  the  action  of 
the  cinders  in  absorbing  moisture,  and  because  it  contained,  there- 
fore, voids  ;  and  secondly,  because  in  addition  to  the  above  condi- 
tions the  cinders  often  contained  oxide  of  iron  which,  when  not 
coated  over  with  the  cement  by  thorough  wet  mixing,  caused  the 
rusting  of  any  steel  which  is  touched.  There  is  one  cure  and  only 
one:  mix  wet  and  mix  well.  With  this  precaution  I  would  trust 
cinder  concrete  quite  as  quickly  as  stone  concrete  in  the  matter  of 
corrosion."* 

7.    ERECTION  OF  REINFORCED  CONCRETE  CONSTRUCTION. 

614.  GENERAL  CONSIDERATIONS.— The  process  of  erec- 
tion of  reinforced  concrete  buildings  has  some  details  in  com- 
mon with  that  of  the  erection  of  buildings  of  ordinary  construction. 
In  other  details,  however,  the  procedure  is  quite  different.  The 
following  are  about  the  usual  steps  in  about  the  order  in  which 
they  are  taken  : 

(1)  The  general  preparation  of  the  site  of  the  building  and  the 

excavation. 

(2)  The  laying  of  the  foundations  for  walls,  piers,  etc. 

(3)  The  erection  of  the  molds  or  forms. 

(4)  The  mixing  of  the  concrete. 

(5)  The  placing  of  the  metal  reinforcements. 

(6)  The  depositing  and  ramming  of  the  concrete  in  the  molds 

or  forms  and  around  the  reinforcements. 

(7)  The  removal  of  the  molds  or  forms  after  the  concrete  has 

set. 


*  See  Report  No.  9,  Insurance  Experiment  Station,  Boston  Manufacturers'  Mutual' 
Fire  Insurance  Company. 


ERECTION. 


727 


(8)  The  finishing  of  the  concrete  surfaces. 

(9)  The  finishing  or  laying  of  the  floor  and  roof  surfaces. 

(10)  The  testing  of  the  completed  structure. 

Details  (3)  to  (7),  inclusive,  are  successive  steps  in  the  process 
of  erection,  which  are  progressive.  That  is,  for  example,  (5) 
and  (6)  may  be  going  on  one  story,  while  (3)  is  going  on  in  a 
story  above,  (7)  in  a  story  below  and  while  (4)  is  going  on  all 
the  time. 

For  the  inspection  of  reinforced  concrete  construction  the 
utmost  competency  and  thoroughness  are  absolutely  essential.  The 
best  designs  and  materials  are  of  no  avail  if  the  work  is  improperly 
done. 

1.  An  inspector  or  superintendent  needs  especially  the  following 
qualifications : 

(1)  Familiarity  with  the  nature  and  qualities  of  the  materials. 

(2)  Knowledge  of  the    principles    of    reinforced  concrete 

design. 

(3)  Activity  and  alertness  in  seeing  that  the  work  progresses 

properly. 

(4)  Watchfulness  to  see  that  proper  tests  of  the  materials  are 

made  as  the  work  goes  on. 

2.  The  inspection  itself  includes,  especially,  in  addition  to  the 
details  already  mentioned : 

(1)  Great  care  in  thoroughly  joining  new  to  previously  laid 

and  partially  set  concrete. 

(2)  The  thorough  cleaning  out  of  forms  and  molds  before 

the  pouring  in  of  the  concrete. 

(3)  The  thorough  and  complete  filling  of  all  parts  of  molds. 

(4)  The  placing  of  all  reinforcements  in  the  exact  position 

they  should  occupy. 
The  above  summary  of  the  details  pertaining  to  the  erection  of 
reinforced  concrete  structures  is  all  that  can  be  attempted  in  this 
book.  Most  of  the  details  have  already  been  generally  discussed 
in  the  preceding  divisions  of  this  chapter  in  connection  with  con- 
crete work  in  general. 

For  detailed  discussions  and  illustrations  of  various  reinforced 
concrete  buildings  to  be  used  for  different  purposes,  the  reader  is 


728 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


referred  to  the  many  recent  treatises  on  this  particular  branch  of« 
masonry  building  construction  and  superintendence. 

4.    CEMENT  AND  CONCRETE  BLOCK  CON- 
STRUCTION. 

615.  INTRODUCTORY.— While  concrete  and  artificial  stone 
has  been  made  and  used  for  centuries,  it  is  only  recently  that  the 
manufacture  and  use  of  concrete  building  blocks  have  rapidly 
developed.  The  recent  growth  of  the  use  of  concrete  blocks  and 
of  machines  for  making  them  has  been  one  of  the  most  rapid  in 
the  whole  cement  trade.  Beginning  its  development  about  the  year 
1900,  the  industry  has  grown  until  there  are  now  (1908)  hun- 
dreds of  patents  in  machines  and  blocks  and  thousands  of  manu- 
facturers of  the  blocks  themselves. 

The  following  are  some  of  the  steps,  in  order,  in  the  early 
history  of  the  manufacture  of  and  use  of  cement  and  concrete 
blocks : 

(1)  Concrete  molded  into  separate  blocks,  used  as  bricks  or 

blocks  of  stone,  and  used  and  introduced  in  the  early 
part  of  the  19th  century. 

(2)  Solid  concrete  blocks  used  at  first,  but  found  to  be  too 

heavy. 

(3)  Hollow  blocks  used  and  left  hollow  in  the  walls,  or  filled 

with  concrete  after  being  placed  there.  Such  blocks 
patented  in  England,  in  1875,  by  Sellers. 

(4)  Concrete  facing  slabs  manufactured  soon  after  1875  and 

made  with  projections  for  securing  them  to  the  con- 
crete filling. 

(5)  Blocks  made  in  Z-shape  and  set  so  as  to  make  hollow  walls. 

These  were  patented  by  Listh,  of  Newcastle,  in  1878, 
and  were  made  by  pouring  wet  concrete  into  the 
molds  and  leaving  it  there  many  hours  before 
removal. 

(6)  Modern   rapid   methods,   American   inventions,   by  which 

hollow  concrete  blocks  are  molded  from  semi- wet 
mixtures  of  a  consistency  that  allows  an  immediate 
removal  from  the  molds,  and  by  wliich  the  manufac- 
ture of  the  blocks  has  been  greatly  simplified  and 
cheapened,  developed  from  about  1900. 


CONCRETE  BLOCK  CONSTRUCTION.  729. 

There  is  a  growing  demand  for  the  material,  and  no  doubt  its  use 
would  have  been  much  more  general  had  it  not  been  for  very 
numerous  poor  results,  both  constructive  and  artistic,  due  to  mis- 
information and  inexperience  on  the  part  of  some  manufacturers, 
builders  and  so-called  designers. 

It  has  been  said  with  truth  that  in  no  department  of  the  cement 
industry  has  the  need  of  standard  specifications  and  uniform 
instructions  been  so  great  as  in  the  manufacture  of  cement  and 
concrete  building  blocks. 

616.  RELATIVE  ADVANTAGES  OF  CONCRETE 
BLOCKS. — Concrete  blocks  are  manufactured  in  factories 
equipped  with  suitable  molds  and  appliances  for  making  and 
thoroughly  curing  them  and  are  then  brought  to  the  building  and 
set  in  place.  Thus  the  main  portion  of  the  expense  in  connection 
with  plain  concrete  walls  built  in  place,  that  is,  the  construction  of 
the  forms  and  the  handling  of  the  concrete,  is  avoided.  The  use  of 
materials  for  veneering,  common  in  some  of  the  better  classes  of 
concrete  buildings,  is  also  unnecessary. 

Another  great  advantage  is  in  the  use  of  shapes  which  result 
in  hollow  walls ;  that  is,  blocks  with  one  or  more  hollow  spaces, 
or  blocks  of  such  shape  that  their  combination  in  a  wall  produces 
hollow  spaces  in  it. 

617.  USES  OF  CONCRETE  BLOCKS  OR  CEMENT 
BLOCKS. — Some  of  the  particular  uses  to  which  cement  blocks, 
or  concrete  blocks  are  put  are  the  following: 

(1)  Foundations  for  various  kinds  of  superstructures. 

(2)  Retaining-walls. 

(3)  Exterior  walls  carrying  loads. 

(4)  Interior  walls  carrying  loads. 

(5)  Fire-walls  and  partitions. 

(6)  Curtain-walls,  exterior  and  interior. 

(7)  Filler  blgcks  for  floor  slabs. 

(8)  Veneering  of  walls. 

(9)  Cornice,  trim  and  ornamental  work. 

(10)  Chimney  flues,  etc.,  etc. 

There  are  increasing  demands  for  these  blocks  for  still  other 
uses,  and  cities  are  beginning  to  recognize  them  as  legitimate 
building  materials  and  to  formulate  requirements  which  must  be 
satisfied  when  they  are  used. 


730 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


618.  MATERIALS  FOR  CONCRETE  BUILDING 
BLOCKS. — The  size  of  the  aggregate  used  is  generally  relatively 
small,  the  gravel  or  stone  not  exceeding  from  ^2  to  ^  inch  in 
size.  At  least  one-third  of  the  material,  by  weight,  should  be 
coarser  than  ^  inch,  and  blocks  made  of  such  gravel  or  screen- 
ings and  mixed  in  the  proportion  of  i  to  5  give  as  good  results 
as  if  made  in  the  proportion  of  i  to  3  with  sand  only. 

Coarse  fragments  do  not  show  on  the  surface  when  the  mixing 
is  thorough. 

Sand  and  gravel  are  generally  the  cheapest  materials  for  con- 
crete block  work. 

If  thoroughly  mixed,  a  small  percentage  of  clay  or  loam  does 
no  harm. 

Stone  screenings,  when  of  good  quality,  result  in  as  strong 
concrete  as  results  from  sand  and  gravel,  and  make  blocks  of  a 
somewhat  lighter  color. 

Cinders  are  occasionally  used  for  block  work.  They  do  not 
develop  great  strength,  but  may  serve  for  some  purposes. 

Lime  in  the  form  of  dry-slaked  lime  or  ''hydrate  lime."  added  to 
si^lock  concrete,  in  the  proportion  of  ^  to  ^  of  the  cement  used, 
gives  it  a  lighter  color  and  makes  the  blocks  denser  and  less  liable 
to  be  permeated  by  water. 

Portland  cement  is  the  cheapest  cement  for  a  given  strength 
in  concrete  block-making  and  is  the  only  hydraulic  material  used 
to  any  large  extent  for  this  kind  of  work.  It  is  uniform,  strong 
and  prompt  in  hardening,  and  gains  as  great  strength  in  air  as  in 
water. 

619.  PROPORTIONS  OF  MATERIALS  FOR  CONCRETE 
BUILDING  BLOCKS.— In  adjusting  the  proportions  of  mate- 
rials for  concrete  building  blocks,  the  most  important  considera- 
tions are  strength,  permeability,  appearance  and  cost. 

Although  mixtures  poor  in  cement,  such  as  i  tcT  8  or  i  to  10, 
may  have  strength  enough,  they  are  extremely  porous.  Again,  a 
poor  mixture  strong  enough  for  a  building  may  not  be  strong 
enough  to  stand  rough  handling  when  in  the  form  of  blocks  at  the 
factory.  Strength  and  hardness  depend  also  upon  the  character 
of  other  materials  for  a  given  proportion  of  sand. 

Experience  seems  to  teach  that  blocks  of  satisfactory  quality 
-cannot  be  made  by  hand-mixing  and  tamping  under  ordinary  fac- 


CONCRETE  BLOCK  CONSTRUCTION. 


731 


tory  conditions  from  a  poorer  mixture  than  i  to  5 ;  and,  for  good 
results,  even  this  proportion  requires  properly  graded  sand  and 
gravel  or  screenings,  plenty  of  water  and  thorough  mixing  and 
tamping.  With  coarse  mixed  sand  only  the  proportion  should  not 
be  less  than  i  to  4.  Good  blocks  cannot  be  made  with  fine  sand 
alone  without  making  the  cost  prohibitory  on  account  of  the  amount 
of  cement  necessary. 

These  i  to  5  and  i  to  4  mixtures  are  more  or  less  porous,  accord- 
ing to  the  character  of  the  grading  of  the  screenings  or  gravel 
used ;  but  the  porosity  can  be  reduced  by  putting  in  some  hydrated 
.  lime  to  replace  a  part  of  the  cement.  This  lime  makes  the  wet 
mixture  more  plastic,  more  easily  compacted  by  ramming  and 
gives  a  lighter  color  to  the  blocks. 

The  following  mixtures'^  have  been  recommended  for  concrete 
blocks,  the  term  ''gravel"  meaning  "a  suitable  mixture  of  sand  and 
gravel,  or  stone  screenings,  containing  grains  of  all  sizes,  from 
fine  to  3^-inch  sizes :" 

I  to  4  Mixtures,  by  Weight. 
Cement  150,  gravel  600. 
Cement  125,  hyd.  lime  25,  gravel  600. 
Cement  100,  hyd.  lime  50,  gravel  600. 

I  to  5  Mixtures,  by  Weight. 
Cement  120,  gravel  600. 
Cement  100,  hyd.  lime  20,  gravel  600. 

The  proportion  of  water  is  an  important  matter  and  afifects 
greatly  the  quality  of  the  work.  Free  water  should  flush  to  the 
surface  when  the  concrete  is  tamped,  and  the  mixture  should  be 
what  is  called  a  ''quaking"  mixture. 

620.  MIXING  THE  CONCRETE.— Thorough  manipulation 
of  the  concrete  mixture  is  very  important.  The  concrete  may  be 
mixed  by  hand  or  by  power-mixers,  and  the  latter  may  be  of  the 
continuous  type  or  may  be  batch-mixing  type.  Power-mixing 
results  in  a  quality  of  product  and  in  a  uniformity  superior  to  that 
resulting  from  hand-mixing.  Of  the  power-mixers  the  batch- 
mixers,  operated  by  steam,  gasoline  engine 'or  electric  motor,  are 
better  adapted  to  concrete  block  work  than  are  the  power-mixers 
■of  the  continuous  type.  There  are  several  types  of  both  continuous 
and  batch  power-mixers.  » 

*  S.   B.   Newberry,  in  "Concrete  Building  Blocks,"  Bulletin  No.    i,  Association  of 
American  Portland  Cement  Manufacturers,  Philadelphia. 


732 


BUILDING  CONSTRUCTION.  (Ch.  X) 


However  mixed,  initial  set  must  be  prevented  by  regulating  the 
size  of  batch  to  capacity  of  machine,  so  that  no  cement  will  be 
"wet  longer  than  thirty  minutes. 

621.  THE  SHAPE  OF  CONCRETE  BLOCKS.— As  has  been 
stated  before,  one  great  advantage  in  using  concrete  block  con- 
struction is  the  opportunity  it  offers  of  obtaining  hollow  walls. 


Fig.  564.    Concrete  Block  with  Four         Fig.    565.     Concrete   Stretcher   Block.  Three 
Webs  and  Three  Air-spaces.  Webs  and  Two  Air-spaces. 


The  principal  advantages  of  hollow  walls  over  solid  walls  may  be 
given  as  follows : 

(1)  Insulation  against  heat  and  cold. 

(2)  Saving  of  material. 

(3)  Greater  resistance  to  the  passage  of  water  and  dampness. 

(4)  A  general  ventilation  of  wall  spaces  and  adjoining  rooms 

through  the  pores  of  the  hollow  concrete  blocks,  and 
a  consequent  elimination  of  sweating  on  the  inside 
of  walls. 


Fig.    566.      Concrete    Corner    Block.      Three        Fig.  567-    Concrete  Stretcher  Block 
Webs  and  Two  Large  Cores.  Faced  with   Lafarge  Cement. 

It  is  important  to  notice  that  the  great  saving  due  to  the  omission 
of  material  from  the  interior  of  walls,  and  the  consequent  profit 
to  the  manufacturer  and  reduction  in  cost  to  the  consumer,  is  accom- 
panied by  sanitary  advantages. 


CONCRETE  BLOCK  CONSTRUCTION. 


733 


622.  BLOCKS  WITH  FOUR  WEBS  AND  TrfREE  AIR- 
SPACES.— Fig.  564  shows  an  early  form  of  hollow  block,  used  in 
many  buildings,  and  a  type  still  followed  by  many  manufacturers. 
There  are  four  transverse  webs,  one  at  either  end  and  two  midway 
of  the  block.  The  form  lends  itself  to  the  use  of  the  essential 
half  blocks,  which  can  be  made  without  change  of  cores ;  and  to 
L-shaped  corner  blocks  which  result  in  a  better  corner  construc- 
tion than  that  obtained  by  butting  the  end  of  one  block  against 
the  side  of  another. 

623.  BLOCKS  WITH  THREE  WEBS  AND  TWO  AIR- 
SPACES.— Fig.  565  shows  a  stretcher  block  of  this  type  with  small 
cores.    Fig.  566  shows  a  three-web  corner  block  with  large  cores,. 


Fig.  569.    Hollow  \^'a]l  of  Solid  Concrete  Blocks. 
Block  Ties. 


and  Fig.  567  shows  a  stretcher  block  of  ordinary  Portland  cement 
faced  with  Lafarge  cement. 

The  type  of  blocks  shown  in  this  -  article  seems  to  be  the  one 
most  used,  judging  by  the  number  of  different  machines  turning 
out  blocks  belonging  to  it. 

624.  BLOCKS  WITH  ONE  AIR-SPACE.— Fig.  568  shows 
the  average  type  of  single  air-space  block,  the  middle  web  being 
omitted  and  only  one  core  being  required.  This  is  a  newer  and  less 
common  form  than  that  shown  in  Figs.  565,  566  and  567.  Some 
of  the  advantages  of  this  type  of  concrete  blocks  are  a  lessening 
of  the  tendency  of  moisture  penetration  during  heavy  rains  because 
of  the  smaller  number  of  cross-partitions;  better  opportunities  for 
thorough  tamping  around  one  core  than  around  two  or  more,  and, 
in  consequence,  for  a  more  thoroughly  and  uniformly  compacted 


734  BUILDING  CONSTRUCTION.  (Ch.  X) 

* 

product ;  less  difficulty  in  releasing  the  blocks  and  removing  the  " 
cores ;  less  danger  of  tearing  the  blocks ;  and  a  slight  saving  in 
materials. 

625.  SOLID  BLOCKS  FOR  HOLLOW  WALLS.— Fig.  569 
shows  solid  concrete  blocks  used  to  build  a  two-piece  wall  with  air- 
space, the  inner  and  outer  portions  being  tied  or  bonded  together  by 
lieader  blocks  crossing  the  air-space  as  shown. 

Fig.  570  shows  a  two-part  concrete  hollow  wall  built  of  splid 
■concrete  blocks,  the  two  parts  of  the  walls  being  tied  together  with 
metal  ties  laid  in  the  mortar  joints. 

In  other  attempts  to  combine  the  one-piece  and  the  two-piece 


Fig.  570.     Hollow  ^^'all  of  Solid  Concrete  Blocks. 
Metal  Ties. 

forms,  solid  slabs  of  concrete  have  been  united  by  metal  rods  or 
ties,  the  ends  of  which  are  imbedded  in  the  inner  and  outer  slabs. 
The  slabs  of  concrete  are  sometimes  brick-shape  or  solid-block- 
shape,  with  all  faces  rectangular,  and  are  sometimes  made  with 
irregular  horizontal  cross-sections. 

Fig.  571  shows  one  form  of  such  blocks,  the  two  slabs  of  con- 
crete being  tied  together  with  four  y^-'mch  galvanized-iron  rods 
imbedded  in  the  block  during  its  manufacture.  Common  dimen- 
sions of  the  block  shown  are :  height,  8  inches ;  length,  24  inches ; 
and  depth  in  the  wall,  from  8  to  16  inches. 

The  object  of  systems  of  blocks  such  as  are  shown  in  Figs.  570 


COXCRETE  BLOCK  COXSTRUCTI OX . 


735 


and  571  is  to  secure  a  continuous  air-space  of  approximately  uni- 
form cross-section  throughout  the  wall. 

Those  who  advocate  this  type  of  hollow  wall  concrete  block  con- 
struction refer  to  the  use  of  metal  with  concrete  in  reinforced  work. 
Those  who  criticise  it  as  faulty  construction  reply  that  the  metal 
in  reinforced  concrete  is  completely  imbedded  and  protected  from 
rust  and  corrosion,  while  the  metal  ties  of  the  connected  con- 
crete blocks  are  for  the  greater  part  without  such  protection,  and 
liable  to  rust  from  the  moisture  penetrating  the  outside  blocks  and 
to  deterioration  from  atmospheric  action. 


626.  TWO-PIECE  CONCRETE  BLOCKS.— In  1902,  in  an 
effort  to  overcome  some  of  the  difficulties  of  manufacture  met  with 
in  making  one-piece  blocks,  the  so-called  ''two-piece  blocks"  for 
hollow  concrete  walls  were  introduced.  Fig.  572  shows  a  portion 
of  a  wall  constructed  of  these  blocks  and  indicates  clearly  the  bond 
and  the  continuous  air-space.  The  shape  of  the  blocks  is  such  that 
those  farming  the  outer  face  bond  with  those  forming  the  inner 
surface  by  the  overlapping  of  projections  in  alternate  courses. 
The  blocks  are  T-shaped,  with  short  reinforcing  arms  at  either  end 
of  the  face  section,  and  they  break  joint  not  only  between  courses. 


Fig.  572.     Twor-piece  Hollow  Concrete  Wall. 


736 


BUILDIXG  COX  ST  ruction:. 


(Ck,  X) 


l)ut  also  laterally  or  transversely  in  every  course^  leavmg^  no  vertical 
joints  extending  through  the  v^all. 

This  form  of  concrete  block  also  results  in  advaaitages  in  reg,a:rd 
to  convenience  in  manufacture.  Interior  cores  are  not  needed  in. 
the  manufacture  of  one-face  blocks,  which  can  thus  be  made  under 
direct  and  instantaneous  pressure  without  the  use  of  a  tamper. 

The  manufacturers  of  these  blocks,  and  also  some  engineering- 
authorities,  claim  that  these  processes  ''permit  of  the  use  of  as 
large  a  percentage  of  water  as  may  be  necessary  to  fulfil  the 
Tequirements  of  standard  engineering  specifications  for  a  medium 
or  quaking  mixture,  and  at  the  same  time  allow  the  use  of  as 
large  size  aggregate  as  may  be  desired and  that  ''tlrus,  not  only 
is  a  much  more  thorough  crystallization  secured  in  the  initial  set 


Fig-  573-     Two-piece  Concrete  Blocks.     Corner  Construction. 

than  is  possible  with  a  dry  mixture,  but  far  greater  strength  and 
density  are  obtained  than  can  be  possibly  in  a  sand  and  cement 
mixture."* 

Fig.  573  shows  the  method  of  constructing  a  comer,  with  comer 
blocks,  bond,  broken  joints,  etc. 

Fig.  574  shows  an  adaptation  of  two-piece  blocks  to  "multiple 
air-space"  construction,  by  which  an  interlocking  bond  is  obtained. 
By  varying  applications  of  the  same  principle,  resulting  in  the  use 
of  a  still  greater  number  of  members,  walls  may  be  built  of  any 

*  See  "Concrete-block  Manufacture,  Processes  and  Machines,"  by  Harmon  Howard 
Rice,  Chapter  VllI,  "Shape  of  Blocks." 


CONCRETE  BLOCK  CONSTRUCTION. 


737 


desired  thickness,  and  for  any  special  requirements,  such  as  those 
of  cold-storage  plants,  ice-houses,  etc. 

Fig.  575  shows  these  blocks  adapted  to  the  backing  of  a  brick- 
veneered  wall,  and  Fig.  576  shows,  them  used  for  the  backing  of 
walls  faced  with  blocks  of  stone,  concrete,  terra-cotta  or  any  other 
material.  The  veneering  materials  are  tied  to  the  concrete  backing 
blocks  with  metal  ties  laid  in  the  mortar  joints  and  thin  veneers 


Fig.  574-     Two-piece  Concrete  Blocks.     Multiple  Air-space. 

carry  none  of  the  weight  coming  upon  the  walls,  the  backing  being 
of  great  strength.  A  hollow-dry  wall  results,  impervious  to  mois- 
ture and  resistant  to  the  transmission  of  heat. 

Fig.  577  shows  some  details  of  hollow  concrete  wall  construction 
in  which  these  two-piece  blocks  are  used  with  various  modifications 
and  adaptations  to  suit  special  Requirements.  The  notations  in  the 
drawings*  shown  indicate  clearly  the  varying  details  of  the 
construction. 


*  Courtesy  of  the  American  Hydraulic  Stone  Company,  Denver,  Col.,  the  manu- 
facturers of  these  blocks  by  the  Ferguson  System  of  Concrete  Construction. 


738 


BUILDING  CONSTRUCTION.  (Ch.  X) 


CONCRETE  BLOCK  CONSTRUCTION, 


739' 


Fig-  577.    Two-piece  Concrete  Blocks.    Details  of  Wall  Construction. 


740 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


Fig.  578  shows  the  method  employed  in  supporting  wood  floor 
joists  and  in  anchoring  them  to  the  concrete  wall  blocks. 
Fig.  579  shows  one  method  of  constructing  wall  flues. 
In  regard  to  the  strength  of  the  blocks  described  in  this  article, 


VtBTiCAi-  Section 


Showing  mantheb  of  supptiCTtNO 

rUOOC  JOISTS  ANDWHCHOCINO  TO 
WAUU  ANCtAORi  EYEBY  SIXTH 
JOIST 


Fig.  578.    Two-piece  Concrete  Blocks.    Joist  Supports. 

tests  of  single  blocks,  21  days  old,  12-inch  by  24-inch  for  12-inch 
walls,  set  on  edge  on  a  plank  and  unsupported  in  any  way,  were 
made  at  the  Allis-Chalmers  Works,  Milwaukee,  Wis.,  showing  a 
crushing  strength  of  2,600  pounds  per  square  inch.  The  blocks 
for  this  test  were  selected  at  random. 


5oi 


^ONcl  iKowr\  by  IRyl^o^ course  A.ov<z<' cou<i<i 


Fig.  579.    Two-piece  Concrete  Blocks.    Flue  Construction. 

The  average  weight  of  the  blocks  varies  from  34  to  60  pounds, 
depending  upon  the  width  of  the  wall. 

The  width  of  walls  or  similar  constructions  may  vary  from  5j4 
inches  up  to  any  width. 

There  is  an  average  of  50  per  cent  of  air-space,  the  percentage 
increasing  with  greater  widths  of  walls. 


1^ 


CONCRETE  BLOCK  CONSTRUCTION.  741 

Facing. — Where  a  block  is  to  be  faced  the  mold  is  filled  with 
a  I  to  7  or  I  to  10  mixture  of  coarse  concrete,  a  quarter  of  an 
inch  is  raked  out  of  the  top  of  the  mold  and  this  space  filled 
with  face  matter  mixed  i  to  2}4  or  i  to  3  of  fine  sand  and  cement. 
The  entire  mass  is  then  compressed  at  once,  giving  a  hard  face 
of  great  density,  which  does  not  tend  to  crack  nor  to  peel  oflf,  as 
is  more  apt  to  be  the  case  with  faces  trowelled  on  after  a  block 
is  made. 


Fig.  580,    One-piece  Coycrete  Block.    Stag-      Fig.  581.    Angular  Concrete  Blocks.  Four- 
gered  Air-spaces.  teen-inch  Wall. 


627.  ONE-PIECE  BLOCKS  WITH  STAGGERED  WEBS 
AND  SPACES. — With  the  idea  of  arranging  the  transverse  webs 
and  air-spaces  so  that  every  web  is  backed  by  an  air-chamber  and 
so  that,  consequently,  no  portion  of  the  solid  concrete  connects 
directly  the  outer  with  the  inner  face  of  the  wall,  a  one-piece  con- 
crete block  has  been  put  upon  the  market,  differing  in  form  and 
principle  from  those  already  described. 

This  type  of  block  is  illustrated  in  Fig.  580,*  which  shows  clearly 
the  construction.  In  the  example  given  one  method  of  joist  or 
beam  support  is  shown  also,  the  spaces  in  the  block  being  used  as 
anchorages  for  the  joist  or  beam  hangers. 

The  section  of  this  block  is  such  that  the  passage  of  moisture  is 
made  difficult  and  reduced  to  a  minimum.  These  blocks  have  been 
used  extensively  and  have  given  general  satisfaction. 

628.  SPECIAL  AND  MISCELLANEOUS  TYPES  OF 
CONCRETE  BLOCKS.— It  is  impossible  here  to  even  enumerate 
the  many  dif¥erent-shaped  blocks  and  the  many  varying  details  in 
all  the  various  systems  used. 

In  the  general  principles  of  the  number  of  air-spaces  and  in  the 

*  Courtesy  of  the  Miracle  Pressed  Stone  Company,  Minneapolis,  Minn. 


742 


BUILDING  CONSTRUCTION. 


(Ch.  X) 


continuity  of  same,  some  systems  are  quite  similar  to  those  already 
described,  but  vary  in  detail  of  shape  of  bkDck  and  shape  of  air-  . 
space. 

Figs.  581  and  582,  for  example,  show  the  general  arrangement 
of  so-called  ''angular  block"  construction,*  in  which  the  blocks  have 
the  general  shape  of  angles,  channels  and  tees,  and  can  be  made 
of  any  thickness  so  as  to  provide  for  air-spaces  of  any  size  and 
for  walls  of  any  thickness. 

Fig.  581  shows  two  adjoining  courses  of  a  14-inch  or  two-block 
wall  with  method  of  bonding  at  corners;  and  Fig.  582  shows  the 
same  for  an  18-inch  or  three-brick  wall. 

Figs.  583  and  584t  show  walls  built  on  the  two-wall  system  with 
E-shaped  concrete  blocks,  each  block  being  reinforced  in  the  con- 
tinuous portion  with  bent  galvanized-iron  wires,  of  sizes  varying 


Fig.  582.    Angular  Concrete  Blocks.    Eighteen-inch  Wall. 

from  No.  9  to  No.  12.  Fig.  583  shows  the  E-shaped  blocks  set 
against  cement  brick  backing  and  tied  to  same  with  wire  wall  ties 
laid  in  the  mortar  joints.  Fig.  584  shows  both  divisions  of  the 
hollow  wall  built  of  the  E-shaped  blocks.  A  sufficient  space  is 
left  between  the  two  divisions  to  insure  a  continuous  horizontal  as 
well  as  a  continuous  vertical  air-space. 

The  metal  reinforcement  has  been  found  especially  efficacious  in 
lintels,  caps,  sills  under  concentrated  loads,  etc.,  and  also  in  blocks 
in  preventing  cracks  from  the  loading. 

In  the  special  examples  given  the  walls  rest  on  a  solid  concrete 
foundation,  between  which  and  the  blocks  is  placed  a  damp-proof 
course  of  slate. 


*  Courtesy  of  the  Fisher  Hydraulic  Stone  and  Machinery  Company,  Baltimore,  Md. 
t  Courtesy   of   Mr.   W.   A.    Schenck,   engineer   of   the   National   Prison   and  Vault 
Engineering  Company,  Washington,  D.  C. 


CONCRETE  BLOCK  CONSTRUCTION. 


743 


A  sufficient  number  of  examples  have  been  given  to  illustrate 
the  principal  types  of  concrete  block  wall  construction,  and  for 
further  and  complete  details  in  any  particular  case  the  manufac- 
turers' catalogues  should  be  consulted. 


Fig.  584.     Reinforced  Concrete  Blocks.     E-shaped  Backing  Blocks. 


629.  PROCESSES  USED  IN  CONCRETE  BLOCK  MANU- 
FACTURE.— There  are  six  different  processes  employed  in  making 
concrete  blocks,  as  follows: 

(1)  The  hand-tamping  process. 

(2)  The  pneumatic  tamping  process. 

(3)  The  process  of  pouring  into  iron  molds. 

(4)  The  process  of  casting  in  sand. 

(5)  The  mechanical  pressure  process. 

(a)  Hand  pressure. 

(b)  Power  pressure. 

{6)  The  hydraulic  pressure  process. 


744 


BUILDING  COXSTRUCTION. 


(Ch.  X) 


Differences  of  opinion  regarding  the  superiority  of  any  one  over 
another  of  these  processes  have  led  to  unhmited  contentions ;  but 
it  seems  to  be  the  opinion  of  a  majority  of  engineers  and  archi- 
tects that  a  more  dense  and  homogeneous  block  can  be  obtained  by 
mechanical  pressure  processes  than  by  any  other. 

630.  FACING  AND  ORNAMENTATION.— Mixtures  gen- 
erally used  for  facing  concrete  blocks  in  their  manufacture  vary 
from  I  and  i  to  i  and  3.  Those  used  for  the  backing  or  the  body 
of  the  blocks  vary  from  i  and  4  to  i,  3  and  4.  The  manner  of 
applying  the  facing  and  casting  it  with  the  body  to  make  a  unit 
and  avoid  a  line  of  cleavage  varies  with  the  kind  of  machine  used. 

The  color  of  the  facing  depends  upon  various  details  of  mate- 
rials, mixing,  added  ingredients,  etc.,  such  as  the  color  of  the 
cement,  sand  and  screenings,  the  purity  of  the  water,  and  the  color 
of  the  pigments,  when  used.  Colors  produced  by  artificial  means 
usually  fade  in  time,  and  unfading  colors  can  be  produced  only  by 
the  use  of  aggregates  of  the  desired  shade. 

A  nearly  water-tight  face  may  be  obtained  by  the  use  of  fine 
sand  and  a  large  proportion  of  cement,  or  by  the  use  of  water- 
proofing compounds. 

The  form  of  the  face  and  the  architectural  or  ornamental  treat- 
ment depend  upon  the  good  or  bad  taste  of  the  designer  and  upon 
the  corresponding  form  of  the  particular  plates  used  in  the  actual 
manufacture  of  the  blocks. 

631.  -MACHINES  AND  MOLDS  FOR  CONCRETE  BLOCK 
MANUFACTURE. — These  may  be  conveniently  divided  into  three 
groups,  as  follows  :* 

"(i)  Machines  and  molds  for  manufacturing  blocks  by  tamping 
a  dry  mixture,  using  a  comparatively  fine  aggregate. 

(2)  Machines  for  compressing  in  molds,  without  tamping,  a 

medium-wet  mixture,  using  an  aggregate  graded 
from  fine  to  coarse. 

(3)  Molds  for  forming  blocks  by  pouring  a  wet  mixture." 
The  objects  of  a  concrete  block  mold  or  machine  are : 

"(i)  Means  for  enclosing  the  mass  during  formation  into  the 
desired  shape  and  size. 
(2)  Means  for  properly  and  quickly  compacting  the  mass. 

*  "Concrete  Block  Manufacture,  Processes  and  Machines,"  by  Harmon  Howard  Rice. 


CONCRETE  BLOCK  CONSTRUCTION. 


745 


(3)  Means  for  giving  desired  variation  to  exposed  surfaces. 

(4)  Means  for  making  a  face  of  texture  differing  from  the 

body  of  the  block. 

(5)  Means  for  rapid  discharge  of  the  product. 

(6)  Means  for  preventing  injury  to  the  block  while  green." 

It  is  not  possible  here  to  describe  various  types  of  machines 
and  processes  of  manufacture,  and  the  reader  is  referred  for 
detailed  information  to  excellent  books  on  the  subject,  such  as  the 
one  by  Mr.  Rice,  referred  to  in  the  footnote  of  this  article,  and 
also  to  the  complete  descriptive  and  illustrated  catalogues  furnished 
by  the  manufacturers. 

632.  DETAILS  OF  BUILDING  CONSTRUCTION.— When 
concrete  blocks  are  used  for  the  foundation  walls  below  grade  they 
are  usually  started  upon  footings  of  solid  and  wet  concrete  of 
proper  width  and  thickness  for  the  weight  carried  and  for  the 
soil  built  upon.  If  the  walls  are  thin  care  must  be  taken  to 
divide  up  long  horizontal  lengths  by  means  of  cross-walls  or  by 
occasional  pilaster  piers. 

Joist  and  Girder  Supports.— ^Th^  methods  vary  with  the  system 
of  blocks  used.  Sometimes  the  joists  run  into  the  walls,  necessi- 
tating narrow  courses  of  blocks  outside  the  ends  of  the  joists  and 
small  blocks  for  filling  in  between,  as  indicated  in  Fig.  578;  and 
sometimes  the  joists  are  hung  and  anchored  by  joist-hangers,  as 
shown  in  Fig.  580. 

A  few  courses  of  solid  concrete  blocks  must  be  used  under 
concentrated  loads  when  the  factor  of  safety  is  not  high  enough 
with  the  area  of  concrete  of  the  hollow  construction.  Instead  of 
using  solid  blocks,  the  material  of  the  hollow  construction  is  some- 
times reinforced  for  greater  strength,  as  shown  in  Figs.  583 
and  534- 

Thickness  of  Walls. — Many  cities  are  now  incorporating  in  their 
building  laws  regulations  for  concrete  block  construction,  and  in 
such  cases  the  architect  and  builder  simply  follow  the  requirements. 
The  thickness  of  walls  required*  for  basement  and  superstructure 
are  usually  the  same  ^s  for  brick  walls,  and  where  city  ordinances 
for  this  construction  do  not  prevail,  for  all  ordinary  work  the  thick- 
nesses 8,  10,  12  and  15  or  16  inches  may  be  safely  used,  10  and  8 
inches  being  used  for  first  and  second  stories  of  a  two-story  build- 


746  BUILDING  CONSTRUCTION,  (Ch.  X) 


ing,  12,  lO  and  8  inches  for  a  three-story  building,  and  15,  12,  10 
and  8  for  a  four-story  building. 

When  used  for  partitions,  concrete  blocks  are  usually  made  4 
inches  thick  for  non-bearing  partitions  and  6  inches  thick  for 
bearing  partitions. 

Metal  wall-plugs,  such  as  are  described  in  Article  361  and  shown 
in  Figs.  209  and  212,  are  the  most  convenient  appliances  for  use  in 
fastening  the  trim  to  the  walls,  the  plugs  being  inserted  in  the 
mortar  joints  between  the  blocks. 

Different  Shapes  for  Constructive  Details. — Various  shapes  are 
made  in  all  systems  of  concrete  block  construction  for  use  in  special 
detailed  parts  of  buildings,  such  as  arches,  door-jambs  and  window- 
jambs,  angles  and  corners  of  walls,  lintels,  sills,  band-courses,  etc. 

Manufacturers'  catalogues  give  full  information  regarding  such 
details.  But  the  only  way  to  advance  the  legitimate  use  of  con- 
crete blocks  in  architectural  work  is  to  stop  the  practice  of  using 
stock  sizes  and  stock  patterns  and  of  adapting  design  and  con- 
struction to  some  particular  make  of  blocks  or  machines.  It  has 
been  said,  with  much  truth,  that  unless  the  block  makers  are  pre- 
pared to  make  blocks  to  fit  the  designs  of  architects,  the  block 
makers  will  finally  have  to  go  out  of  business. 

633.  BUILDING  REGULATIONS  FOR  CONCRETE 
BLOCKS. — In  many  of  the  larger  cities  regulations  giving  the 
requirements  for  this  kind  of  construction  have  already  been  care- 
fully formulated  and  incorporated  into  the  building  codes. 

Some  of  these  building  ordinances  relating  to  concrete  block  con- 
struction show  exhaustive  study  and  care  in  their  preparation,  and 
the  reader  is  referred  to  Chapter  XIII,  ''Specifications,"  for  some 
of  these  regulations. 

i 


Chapter  XI. 

Iron  and  Steel  Supports  for  Mason- 
work.    Skeleton  Construction. 


634.  INTRODUCTORY.— Althougii  constructions  of  iron  and 
steel  do  not  properly  come  within  the  scope  of  this  volume,  there 
are  so  many  places  where  metalwork  is  used  in  connection  with 
•brick,  stone  and  terra-cotta  that  it  has  been  thought  desirable  to 
^briefly  describe  the  most  common  forms  of  iron  and  steel  construc- 
tion used  for  supporting  masonry  walls,  and  the  various  minor 
details  of  metalwork  used  in  connection  with  the  masonwork. 

635.  GIRDERS  AND  LINTELS.— All  openings  in  masonry 
walls  which  it  is  not  feasible  to  span  with  arches  should  have  iron 
or  steel  lintels  or  girders  to  support  the  masonwork  above.  The 
objections  to  wooden  beams  for  supporting  masonwork  are  given 
in  Article  361. 

Since  the  price  of  rolled  steel  has  been  so  greatly  reduced,  girders 
and  lintels  for  supporting  brick  and  stone  walls  are  almost  univer- 
sally formed  of  steel  I-beams  or  girders  built  up  of  steel  plates  and 
angle-bars.  Except  for  very  wide  spans  and  exceptionally  heavy 
loads,  steel  I-beams  may  be  most  economically  used  for  such  sup- 
ports. As  a  rule,  at  least  two  beams  should  be  used  to  support  a 
■9-inch  or  12-inch  wall,  and  three  beams  for  a  16-inch  wall,  the  size 
of  the  beams,  of  course,  depending  upon  the  weight  to  be  supported. 
The  beams  should  be  connected  at  their  ends,  and  every  4  or  5  feet 
between,  with  bolts  and  cast-iron  separators,  cast  so  as  to  exactly 
fit  between  the  beams.  The  girders  should  have  a  bearing  at  each 
end  of  at  least  6  inches,  and  should  also  rest  on  cast-iron  bearing- 
plates  of  ample  size. 

If  the  wall  to  be  supported  is  of  brick,  the  first  course  above  the 
girder  should  be  laid  all  headers.  The  width  of  the  girder  is  gener- 
ally made  2  inches  less  than  that  of  the  wall.  In  calculating  the 
weight  to  be  supported  by  a  girder,  much  depends  upon  the  struc- 
ture of  the  wall  above.    If  the  wall  is  without  openings,  and  does 


747 


748 


BUILDING  CONSTRUCTION..         (Ch.  XI> 


not  support  floor  beams,  only  the  portion  of  the  wall  included  within 
the  dotted  lines.  Fig.  585,  need  be  considered  as  the  portion  sup- 
ported by  the  girder.  The  beams  composing  the  girder  in  that  case,, 
however,  should  be  made  very  stiff,  so  as  to  have  little  deflection. 
If  there  are  several  openings  above  the  girder,  and  espcially  if  there 
is  a  pier  over  the  middle  of  it,  as  shown  in  Fig.  586,  then  the  manner 
in  which  the  weight  bears  upon  it  should  be  carefully  considered. 
In  a  case  such  as  is  shown  in  Fig.  586  the  entire  dead  weight  in- 
cluded between  the  dotted  lines  A  A  and  B  B  should  be  considered 


A  B 


Fig.  586.  Onenings  over  Girder.  Amount 
of  Brickwork  Supported. 


as  coming  on  the  girder,  and  proper  allowance  made  for  a  concen- 
tration of  the  greater  part  of  the  load  at  the  middle  point  of  the 
span. 

When  beams  are  used  to  support  an  entire  wall,  running  under 
its  entire  length,  and  when  the  wall  is  longer  than  sixteen  or 
eighteen  feet,  the  whole  weight  of  the  wall  should  be  taken  as 
coming  upon  the  beams ;  because,  if  the  beams  bend,  the  wall  will 
settle  and  have  a  tendency  to  push  out  the  supports  and  to  cause, 
the  entire  structure  to  fall. 


CAST-IRON  LINTELS. 


749 


Steel  lintels  for  supporting  stone  or  terra-cotta  caps  and  flat 
arches  are  described  in  Article  280. 

636.  CAST-IRON  LINTELS.*— Lintels  of  cast-iron  were  at 
one  time  extensively  used  for  supporting  brick  walls  over  store 
fronts  and  door  openings,  and  even  at  the  present  time  are  used  to 
some  extent.  On  account  of  the  brittle  character  of  this  metal, 
however,  and  of  its  low  tensile  strength,  it  should  not  be  used  for 
beams  subjected  to  moving  loads,  such  as  loads  coming  from  floors 
upon  which  heavy  articles  are  moved. 

Cast-iron  beams  of  long  span  are  not  as  economical  as  those 
made  of  rolled  steel.  About  the  only  places,  therefore,  in  which 
cast-iron  lintels  may  be  suitably  and  economically  used  are  those 
over  store  fronts  where  the  span  does  not  exceed  8  feet,  and  those 
over  door  openings  in  unfinished  brick  partitions  where  a  flat  head 


Fig.  587.     Cast-iron  Lintel.    Common  Shape.  Fig.  588.  Cast-iron 

Lintel.  Two  Webs. 

is  necessary.  The  relative  cost  of  cast-iron  and  steel  lintels  depends 
largely  upon  the  distance  from  the  rolling-mills  and  upon  the  freight 
rates.  Foundries  for  casting  iron  are  much  more  widely  dis- 
tributed than  are  rolling-mills,  so  that  castings  of  almost  any  shape 
can  usually  be  obtained  in  any  city  of  twenty  thousand  inhabitants; 
while  mills  for  rolling  steel  beams  are  comparatively  few  in  number, 
and  most  of  them  are  located  in  the  extreme  eastern  portion  of  the 
country. 

The  common  shape  for  cast-iron  lintels  over  door  openings  is  that 
shown  in  Fig.  587.    The  width  of  the  flange  is  usually  made  the 
,   full  thickness  of  the  wall,  and  the  extreme  height  of  the  lintel  at 
the  middle  of  the  span  is  not  less  than  two-thirds  of  nor  greater 
than  the  width  of  the  flange.    The  strength  of  the  lintel  may  be 


*  The  reader  is  referred  to  Kidder's  "Architect's  and  Builder's  Pocket-Book,"  Chapter 
XVI,  "StreYigth  of  Cast-iron,  Wooden  and  Stone  Beams,"  for  a  discussion  of  the  strength 
of  cast-iron  lintels,  illustrative  examples  and  tables  of  strength. 


750  BUILDING  CONSTRUCTION,  (Ch..  XI) 


somewhat  increased  by  stiffening  the  web  in  the  middle  by  brackets, 
as  shown  by  the  dotted  Hnes  at  A. 

Where  the  width  of  the  flange  must  be  over  i6  inches  two  webs 
should  be  used,  as  shown  in  the  section  drawing,  Fig.  588.  For 
handling  and  molding  it  is  better  to  make  the  flange  not  more 
than  24  inches  wide ;  if  a  greater  width  than  this  is  required^  several 


Fig.  589.    Cast-iron  Store  Front  Lintel. 


hntels  should  be  placed  side  by  side.  The  thickness  of  the  metal 
should  be  not  less  than  ^  of  an  inch,  and  the  web  should  be  about 
yi,  of  an  inch  thicker  than  the  flange. 

When  proportioned  as  above  the  strength  of  the  lintel  to  support 
a  dead  load  may  be  safely  made  equal  to 

9700  X  area  of  bottom  flange  X  extreme  depth 
span  in  inches. 

Thus  a  lintel  of  6  feet  clear  span,  with  a  12-inch  by  ^-inch  flange 
and  an  extreme  depth  of  12  inches,  should  safely  support 
9700  X  9  X  12 

 —  —  14,550  pounds. 


Fig.  590.    Cast-iron  Store  Front  Lintel.   Front  Finish. 


Lintels  over  store  fronts  should  be  made  with  ribs  at  the  ends,  as 
■shown  in  Fig.  589,  and  with  holes  for  bolting  the  lintels  to  each 
other  and  to  the  columns.    Store  front  lintels  are  also  occasionally 


CAST-IRON  ARCH  GIRDERS. 


751 


made  as  shown  in  Fig.  590,  in  order  to  form  a  finish  above  the 
openings. 

Fig.  591  shows  details  for  a  cast-iron  hntel  and  sill,  a  form  some- 
times used  for  windows  in  exterior  walls.  The  thickness  of  the 
metal  need  not  exceed  ^  of  an  inch. 

637.  CAST-IRON  ARCH  GIRDERS.^^^— These  also  are  some- 
times used  to  support  brick  and 
stone  walls  in  which  the  openings, 
are  from  10  to  30  feet  in  width. 
Fig.  592  shows  one  of  this  kind  of 
girders  used  to  support  a  central 
tower  over  the  crossing  of  the 
nave  and  transept  in  St.  John's- 
Church,  Stockton,  Cal.,  Mr. 
A.  Page  Brown,  architect.  The 
clear  span  is  2gys  feet,  and  the 
height  of  the  wall  above  the  gir- 
der 18  feet.  One  object  in  using 
such  a  girder  in  this  place  was  to  get  the  height  in  the  middle  of 
the  spans  without  at  the  same  time  raising  the  supports,  which 
could  not  be  accomplished  with  steel  plate-girders.  The  church 
has  a  vaulted  ceiling  which  comes  just  below  the  arched  girder,, 
the  tie-rod  being  exposed. 


2^<f'f'  J       Section  at  Center. 


Fig.    592.     Cast-iron   Arch  Girder. 

The  rise  of  the  casting  in  this  case  is  rather  greater  than  usual^ 
the  ordinary  rise  being  from  Vio  ys  of  the  span.  The  end  of  the 
girder  is  generally  cast  in  the  form  of  a  hollow  box,  with  shoulders 
to  receive  the  ends  of  the  rods.  The  tie-rods  are  often  made  with 
square  ends,  and  about  ^  inch  shorter  than  the  castings,  and  are 
heated  until  the  expansion  allows  them  to  be  slipped  into  their 

*  The  reader  is  referred  to  Kidder's  "Architect's  and  Builder's  Pocket-Book."  Chapter 
VIII,  Articles  "Cast-iron  Arch  Girders  with  W^rought-iron  Tension  Rods"  and  "Rules  for 
Calculating  Dimensions  of  Girder  and  Rod,"  for  formulas,  table  and  additional  illustra- 
tions. 


Fig.  591.     Detail.  Section.  Cast-iron 
Window  Lintel  and  Sill. 


752 


BUILDING  CONSTRUCTION. 


(Ch.  XI) 


places  in  the '  castings.  As  they  cool,  the  contraction  binds  each 
tightly  into  its  place.  If  a  rod  is  tightened  by  means  of  a  screw  and 
nut,  the  nut  and  bearings  should  be  dressed  to  a  smooth  surface  and 
the  rod  turned  up  with  a  long-handled  wrench.  It  is  very  essential 
that  the  rod  shall  be  fitted  into  place  so  tightly  that  no  tensile  stress 
can  be  developed  in  the  casting;  and  it  should  not  be  expanded  to 
such  an  extent  that  initial  stresses  are  caused  in  the  arch. 

This  form  of  girder  is  comparatively  little  used  now,  but  there 


Fig-     593-      Corbelled    Stone    V/all  Fig.     591.      F>ay-\v'nflow  Supports. 

Support  for  Bay-window.  .  Cast-iron  Brackets. 


may  be  conditions,  as  there  were  in  the  church  mentioned  on  pre- 
ceding page,  under  which  it  can  be  used  to  advantage. 

638.  SUPPORTS  FOR  BAY-WINDOWS.— Or^/man-  Con- 
struction.— Where  bay-windows  having  walls  of  brick,  stone  or 
terra-cotta  start  above  the  first  story  it  is  necessary  to  support  them 
in  some  way  by  metal  work. 

If  the  bottom  of  the  bay  is  of  stone,  and  the  projection  is  not 
more  than  2  feet,  the  bay  may  be  supported  directly  from  the  wall 
by  corbelling  out  the  stonework,  as  shown  in  Fig.  593.  The  stone 
A  should  be  the  full  size  of  the  bay  if  possible,  and  should  be  bolted 
down  by  means  of  long  rods  built  into  the  wall  and  secured  to  two 
channel-bars,  as  shown  in  the  figure,  placed  on  top  of  the  stone  and 
having  their  ends  built  into  the  main  wall. 

If  the  bottom  of  the  bay  is  of  copper,  and  at  a  floor  level,  the 


BAY-WINDOW  SUPPORTS. 


753 


simplest  and  strongest  method  of  supporting  the  bay  is  the  one 
shown  in  Fig.  595. 

Steel  I-beams  are  extended  across  the  wall  of  the  story  below  and 
framed  to  a  pair  of  channels,  bent  to  the  shape  of  the  bay.  The 
I-beams  should  be  carried  far  enough  inside  of  the  walls  to  give 
them  a  sufficient  anchorage  to  offset  the  leverage  of  the  other  ends, 
and  they  should  be  secured  to  a  girder  or  to  a  partition  running 
parallel  with  the  wall,  or  to  another  steel  beam  running  at  right- 
angles  to  thern,  and  forming  a  part  of  the  floor  construction. 

The  channel-bars  forming  the  supports  for  the  walls  of  the  bay 
should  also  be  built  into  the  wall  on  each  side  and  anchored  to  it 
by  iron  rods  built  into  the  rnasonry  below. 

Fig.  594  shows  a  method  of  supporting  a  light  bay  by  cast-iron 


Fig-   595-     Bay-window  Supports.     Steel  Beams  and  Channels. 


brackets  bolted  to  the  wall.  This  method  has  been  used  where  the 
bottom  of  the  bay  is  above  the  floor  line.  The  bottom  of  the  bay 
in  this  construction  may  be  of  either  copper  or  terra-cotta,  the  latter, 
if  used,  being  suspended  from  the  brackets  by  hook  anchors.  If 
such  a  construction  is  used  a  steel  channel  should  be  bolted  to  the 
top  of  the  wall  back  of  the  bay  and  extended  well  into  the  side  walls, 
to  prevent  the  brackets  from  pulling  away  the  brickwork.  Examples 
of  bay  supports  in  skeleton  construction  are  shown  also  in  Figs. 
614  and  615. 

639.  WALL  SUPPORTS  IN  SKELETON  CONSTRUC- 
TION.*— In  buildings  of  the  ''skeleton"  type,  now  so  generally 
used  for  high  office-buildings,  all  the  weight  of  the  walls,  at  least 


*  For  a  more  extended  discussion  of  curtain-walls  and  of  masonry  surrounding  outer 
columns  the  reader  is  referred  to  Freitae's  "Architectural  Engineering"  and  to  Birkmire's 
"Planning  and  Construction  of  High  Office  Buildings  " 


754 


BUILDING  CONSTRUCTION.  (Ch.  XI). 


all  above  the  third  story,  including  the  masonry  surrounding  the- 
outer  columns,  is  supported  by  the  steel  skeleton  frame.  The  outer 
walls  of  the  lower  stories,  when  of  stonework,  are  sometimes  sup- 
ported directly  from  the  foundations,  as  was  the  case  in  the  New 
York  Life  building,'^  Chicago,  and  in  many  other  buildings  erected 
since. 

When  the  walls  are  supported  by  the  steel  skeleton  they  are  gener- 
ally made  very  thin,  generally  about  12  inches  and  sometimes  only 
9  inches  in  thickness;  and  in  the  more  recent  buildings  the  walls 
are  supported  at  every  story,  so  that  a  wall  in  any  story  can  be 
removed  without  affecting  the  wall  above  or  below. 

The  materials  generally  used  for  the  outer  walls  are  brick  and 
terra-cotta,  these  being  preferred  on  account  of  the  ease  with  which 
they  may  be  handled  and  built  about  and  between  the  beams  and 


Lines  C~C  on  center  of  Columns 

Fig.  596.    Spandrel  Wall  Supports.    Champlain  Building,  Chicago. 

columns.  Brick  and  terra-cotta  appear  also  to  rank  as  the  best  heat- 
resisting  materials  for  the  walls  of  fire-proof  buildings. 

It  is  somewhat  more  difficult  to  attach  stonework  to  the  metal 
frame,  and  this,  together  with  the  low  fire-resisting  qualities  of  most 
building  stones,  makes  the  us'e  of  this  material,  except  in  the  lower 
stories,  very  much  less  desirable.  Stone  has,  however,  been  very 
recently  used  for  the  entire  outside  casing  of  some  very  high  and 
very  important  buildings. 

The  general  plan  of  the  exterior  walls  in  this  class  of  buildings 
consists  of  vertical  piers,  from  3  to  4  feet  wide,  which  inclose  the 
exterior  columns  and  extend  from  the  bottom  to  the  top  of  the 


*Jenney  &  Mundie,  architects. 


SPANDREL  WALL  SUPPORTS. 


755 


building.  The  space  between  these  piers  is  generally  nearly  filled  by 
the  windows,  either  flat  or  in  the  form  of  bays,  leaving  only  a  small 
piece  of  wall,  from  4  to  5  feet  high,  between  the  tops  and  bottoms 
of  the  windows,  to  be  supported  by  the  steel  frame.  These  portions 
of  walls  between  the  piers  and  the  windows  are  called  "spandrels." 

The  masonwork  of  the  piers  is  generally  supported  by  angle 
brackets  attached  to  the  columns,  and  the  spandrels  are  supported 
by  steel  beams  or  girders  of  various  shapes,  and  called  "spandrel 


I^ig-  397-    Spandrel  Wall  Supports.    Wyandotte  Building,  Columbus,  Ohio. 

beams."  The  spandrel  beams  extend  from  column  to  column,  and 
are  rivetted  to  them. 

The  arrangement  of  the  metalwork  for  supporting  the  spandrel 
walls  will  depend  largely  upon  the  architectural  effect  sought  by 
the  designer  and  upon  the  materials  used ;  so  that  the  details  vary 
somewhat  in  every  building,  and  often  in  different  portions  of  the 
sam.e  building.    No  general  rule  or  form  of  construction  can  there- 


756  BUILDING  CONSTRUCTION.  (Ch.  XI) 


fore  be  given  for*arranging  such  supports,  and  the  architect  must 
use  such  arrangements  as  seem  best  suited  to  the  design  of  the 
building  he  has  in  hand.  The  following  examples,  however,  will 
show  how  the  walls  have  been  supported  in  several  buildings,  and 
with  slight  variations  one  or  another  of  these  methods  can  be 
adapted  to  almost  any  building. 

It  is  probably  hardly  necessary  to  say  that  the  metalwork  in  this 
class  of  buildings  should  be  very  carefully  designed  and  studied  to 
suit  the  conditions  of  the  building  and  to  provide  ample  strength ; 
and  it  should  also  be  so  arranged  that  it  may  be  fully  protected  from 


S  6'OM 
T  C. 


Fig.  598.    Spandrel  Wall  Supports.    New  York  Life  Building,  Chicago. 

heat.  Consideration  is  also  sometimes  given  to  the  effects  of  expan- 
sion and  contraction  in  the  frame. 

640.  SPANDREL  SUPPORTS.— The  simplest  case  of  spandrel 
supports  is  the  one  in  which  the  walls  are  perfectly  plain  and  built 
of  brick,  with  terra-cotta  caps  and  sills.  In  such  cases  a  channel 
and  an  angle-bar  may  be  used  to  support  the  outer  face  of  the 
wall,  and  an  I-beam  to  support  the  backing,  as  indicated  in  Fig.  596, 
which  shows  sections  of  the  outer  walls  of  the  Champlain  building, 
Chicago.* 

The  channel  and  I-beam  should  be  bolted  together  with  cast-iron 
separators  made  to  fit. 


*  Holabird  &  Roche,  architects. 


SPANDREL  WALL  SUPPORTS. 


757 


For  plain  walls,  channels  and  angles  seem  to  be  the  best  shapes 
for  the  outer  portion  of  a  spandrel  support,  as  they  are  economi- 
cal sections,  and  the  flat  face  of 
the  channel  being  turned  out- 
ward, a  4-inch  veneer  of  brick- 
work can  be  set  in  front  of  it 
without  clipping  the  bricks.  The 
face  of  the  channel  is  generally 
set  5  or  6  inches  back  from  the 
face  of  the  wall,  and  3-inch  by 
3-inch  angles  are  used  for  the 
purpose  of  supporting  the  outer 
4  inches  of  the  wall.  The  outer 
edge  of  the  angle  should  come 
within  2^4  inches  of  the  face  of 
the  wall. 

Spandrel  supports  very  similar 
to  those  shown  in  Fig.  596  have 
been  used  in  several  Chicago 
buildings. 

Z-bars  also  were  used  in  sev- 
eral buildings  in  place  of  the 
channels  and  angles,  but  were 
generally  considered  not  quite  as 
satisfactory,  as  they  do  not  give 
the  same  strength  for  the  weight 
of  metal  used'.  They  are  no 
longer  used. 

Fig.  597  shows  a  Z-bar  sup- 
port used  for  the  attic  wall  of 
the  Wyandotte  building,  Columbus,  Ohio.* 

Fig.  598,  from  the  New  York  Life  Insurance  Company's  build- 
ing, Chicago,  shows  the  spandrel  supported  by  a  single  I-beam,  the 
4-inch  facing  of  the  wall  being  supported  by  the  terra-cotta  lintel 
which  is  hung  from  the  beam. 

In  the  Reliance  building,f  plate-girders  were  used  for  the  main 
spandrel  supports,  and  two  angles  rivetted  together  to  make  a  T 


T'ig-  599-    Spandrel  Wall  Supports.  Masonic 
Temple,  Chicago. 


*  D.  H.  Rurnliam  &  Co.,  architects, 
t  D.  H.  Burnham  &  Co.,  architects. 


758 


BUILDING  CONSTRUCTION.  (Ch.  XI) 


were  bracketed  from  the  outer  face  of  the  girder  to  support  the 
wall,  the  g-irder  being  on  the  center  line  of  the  columns. 

Fig.  599  shows  the  method  used  for  supporting  the  granite  walls 
at  the  fourth  floor  level  of  the  Masonic  Temple,  Chicago.  It  should 
be  noticed  that  an  open  joint  is  left  opposite  the  supporting  angle  to 
allow  for  expansion  and  contraction  in  the  steel  columns. 

When  the  wall  is  faced  with  ornamental  terra-cotta,  the  latter  can 
seldom  be  supported  directly  by  the  spandrel  beams,  and  a  system  of 
anchors  must  be  resorted  to  to  properly  tie  the  individual  blocks 
either  to  the  brick  backing  or  to  the  metalwork.    These  anchors  are 


4'   'O*?  T£R-fl/^  Q-^'Iji 
A80VC 


Fig.  6oo.    Spandrel  Wall  Supports.    New  York  Life  Building,  Chicago. 


usually  made  of  ^-inch  square  or  round  iron  rods,  which  are 
hooked  into  the  ribs  provided  in  the  terra-cotta  blocks,  and  then 
drawn  tight  to  the  brickwork  or  metalwork  by  means  of  nuts  and 
screw  ends,  as  shown  in  Fig.  614. 

Hook-bolts  are  largely  used  for  tying  terra-cotta  blocks  to  the 
metalwork,  the  ends  being  bent  around  the  bottom  of  the  beams, 
channels  or  angles.  Several  examples  of  the  use  of  hook-bolts  are 
shown  in  Figs.  598  to  615. 

A  great  variety  of  methods  for  properly  securing  the  terra-cotta 


SPANDREL  WALL  SUPPORTS. 


759 


are  possible.  They  should  be  carefully  studied  and  the  general 
scheme  should  always  be  indicated  on  the  spandrel  sections,  in  the 
manner  shown  in  the  illustrations,  as  the  holes  in  the  structural 


Two  exAiTvples  ^hoAviivg    trea-trrveivt    oF   ^/revea-L  ; 

Oivc-  aLivclvorccL    Uvro'  cKctaivcL  web    tKe.  otKer 

over  top  of  an-gle  wKvcK.  is  5ep*.ra.lecL  from.  be&.nv.*' 


6       3       O  1 

Inches  i-r+J 

1  1  1  1  1  1  1  ;  1  1  i  ^  1  t  1  1  1  - 



Fig.  6oi 


Steel  Supports  for  Masonry.    Terra-cotta  Lintel 
Construction. 


metalwork  necessary  to  receive  the  anchors  should  be  shown  on  the 
detail  drawings  of  the  iron  and  steel  work,  so  that  the  punching 
may  be  done  at  the  shop.  The  inexperienced  architect  should  also 
consult  with  the  manufacturers  of  the  terra-cotta  work  as  to  the 
best  manner  of  securing  the  blocks. 

The  anchorage  of  the  brick  and  terra-cotta  to  the  steel  frame  is  a 


Rear  and   rroul    Llcvatioiis  of   Lintel  j 
(Showing   niethocl     of    hongiii^     t)  explain- 
ing   runctions    of    clipa^  dowels,  hangew,  ePc  . 


.Section 
Note    all  elf  (to 
.brickw  o'  k 


Fig.  6o2.     Steel  Supports  for  Masonry.    Terra-cotta  Lintel  Construction. 

matter  of  vital  importance,  as  very  serious  consequences  are  quite 
sure  to  follow  any  neglect  in  this  matter.  '*An  instance  is  known 
where  a  whole  section  of  wall  facing  on  the  court  side  of  a  high 


ft 


760 


BUILDING  CONSTRUCTION.  (Ch.  XI) 


building  fell  off  because  the  workmen  omitted  the  anchors."  As  all 
the  anchors  for  every  block  cannot  be  exactly  shown  on  the  draw- 
ings, either  the  architect  or  some  one  in  his  employ  should  give  this 
portion  of  the  work  the  strictest  superintendence. 

641.  STEEL  LINTEL  SUPPORTS  FOR  MASONRY.*— 
Figs.  601  to  612,  both  inclusive,  illustrate  various  forms  of  metal 
supports  for  curtain  walls  and  terra-cotta  lintels. 

Fig.  601  shows  two  examples  indicating  the  treatment  of  4-inch 
reveals.    One  shows  an  anchor  through  the  channel  web  and, the 


Figf.  603.    Steel  Supports  for  Masonry.  Fig.  604.   Steel  Supports  for  Masonry. 

Shelf  Bearing  and  Rod  Suspension.  Terra-cotta  Lintel  Construction. 


Other  a  tie  or  anchor  hooked  over  the  top  of  the  steel  angle  which 
is  separated  from  the  I-beam. 

Fig.  602  shows  section  and  front  and  rear  elevations  of  metal 
supports  for  terra-cotta  lintels  and  masonry  above.  The  section 
shows  the  angle  shelf  for  supporting  the  4-inch  brick  facing,  and  the 
two  elevations  show  the  method  of  hanging  and  the  functions  of  the 
clips,  dowels,  hangers,  etc. 

Fig.  603  shows  curtain-wall  supports  with  angles,  brackets,  hook- 
bolts,  etc.,  for  holding  up  double  terra-cotta  lintel  and  masonry 
above. 

*  These  illustrations  are  reproduced  through  the  courtesy  of  the  Northwestern  Terra* 
cotta  Company,  of  Chicago,  111. 

% 


WALL  AND  LINTEL  SUPPORTS. 


Fig.  604  shows  the  steel  supports,  and  a  single  terra-cotta  liniel 
resting  on  angle  shelf  and  also  hung  on  hook-bolt,  and  the  wall 
facing  above  resting  on  angle  shelf  fastened  to  steel  bracket  from 
the  plate-girder. 

Fig.  605  shows  metal  supports  formed  by  I-beam,  angle  and 
anchor.  The  terra-cotta  lintel  has  a  shelf  bearing  with  anchor 
clamped  over  top  flange  of  beam.  The  stafif-bead  is  so  placed  that 
the  terra-cotta  lintel  will  not  be  injured  from  any  deflection  of  the 
I-beam. 

Fig.  606  shows  metal  supports  formed  by  I-beam,  channel,  three 


;Lu\.tel  witk  sK-clf  beMLiv^  v'ltK. 

i^^ncKor  claLirvj^ed  over  tolp  [Lev-rv^e 
beJiJtv—  Note  a^rroLiv^emervt  of 
^t^ff  heojA  for  [jreveivtlrvg  iwjury  to^ 
TC*  by  deflection,  of  bea^nx- 

Fig.  605.   Steel  Supports  for  Masonry. 
I-beam,  Angle  and  Anchor. 


\E/Xajivple  .sKowiivg-  liiv.tet 
^uap^ivdetL  fronv  slvelTj  — 
jtKii  ^KelF  <3uppor  thi^  brtckworlv 

Fig.  606.    Steel  Supports  for  Masonry.. 
I-beam,  Channel,  Three  Angles 
and  Hook-bolt. 


angles  and  a  hook-bolt.  The  terra-cotta  lintel  is  suspended  from  the 
angle  shelf,  and  this  same  shelf,  formed  by  the  long  horizontal  leg 
of  the  angle,  supports  the  8-  or  9-inch  brick  facing  of  the  wall  above. 

Fig.  607  shows  metal  supports  formed  by  I-beam,  channel,  angle 
and  hook-bolt.  In  this  example  there  is  a  double  terra-cotta  lintel, 
the  outer  one  being  supported  by  the  long  angle  shelf  rivetted  to 
the  channel  web  and  anchored  to  top  flange  of  channel,  the  inner 
or  lower  one  being  hung  by  a  hook-bolt  from  a  plate  resting  on 
lower  flanges  of  the  I-beam  and  the  channel. 


-762 


BUILDING  CONSTRUCTION.  (Ch.  XI) 


Fig.  608  shows  metal  supports  formed  by  plate-girder,  channel, 
two  angles,  anchor  and  hook-bolt.  The  outside  lower  lintel  of  terra- 
cotta is  supported  by  an  angle  shelf  rivetted  to  lower  part  of  channel 
web,  and  is  also  tied  or  anchored  back  by  anchor  running  through 
channel  web.  This  shelf  and  its  supported  terra-cotta  lintel  also 
supports  the  terra-cotta  wall  facing  above.  The  terra-cotta  soffit 
is  supported  by  a  hook-bolt  run  through  a  steel  plate  resting  on  lower 
flanges  of  channel  and  plate-girder. 

Fig.  609  shows  metal  supports  formed  by  two  channels,  two 


Double  Liivt el,  Or\e  wtllv  sK.eLf  Wc^rKo  tcuvo* 
eAcKored  to  top  flarv.c»e  of  cKaatveL  6*  tKe  otl\&i* 
Kuiv,o'  by  Ti\e»>Tvs  of  K.ji.R^er6 

Eig.  607.     Steel  Supports  for  Masonry. 
I-beam  Channel,  Angle,  Plate 
and  Hook-bolt. 


ajvckoretL  tkroagK.  cK».i\.ael.  vcb,  t> 
<3offil  Kuivg  by  T(\G-b~i\xs  of  KoL^tv^erA 


Fig.  608.    Steel  Supports  for  Masonry. 
Plate-girder,  Channel,  Two  Angles, 
Anchor  and  Hook-bolt. 


angles,  anchor  and  hook-bolts.  The  terra-cotta  face  lintel  is  bedded 
on  the  angle  shelf  rivetted  to  channel  web  and  also  anchored  back 
by  anchor  caught  around  top  flange  of  channel.  The  soffit  is  sus- 
pended by  hook-bolts  through  a  steel  plate  resting  on  the  lower 
flanges  of  channels. 

Fig.  610  shows  metal  supports  formed  by  I-beam,  channel,  angle 
and  hook-bolt.  The  terra-cotta  outside  face  lintel  rests  on  an  angle 
shelf  and  is  also  tied  back  by  anchor  running  over  top  of  channel 
flange.  The  soffit  is  suspended  by  an  outside  hook-bolt  and  also  has 
its  inside  edge  supported  on  the  lower  flange  of  the  I-beam. 


WALL  AND  LINTEL  SUPPORTS. 


763 


iVTrv.  pie  vsKovvitvg  ^u^petv<ie<^L 
Soffit  J  wutK  fis^ce  of  llivtcL 
bedded   oiv-   v-slvelP^   s^rvd  iMvchored) 
to  top   fle^ivo,e.  o^'    cl\a.i\n-eL  ' 

Fig.   609.    Steel   Supports  for  Masonry. 

Two  Channels,  Two  Angles, 
Anchor  and  Hook-bolts. 


Tke  sofrLl  XK.   U.V15  Cd^e  i?. 
botlv   sSu-spcivdecL  e^^kA  bcdcloH 
On.  be^vnv  flAao'e     Ike  upper 

Fig.  610.   Steel  Supports  for  Ma- 
sonry.   I-beam,  Channel,  Angle, 
Anchor  and  Hook-bolt. 


Vide  .3<»||"ity'  A-sLouU   \>e  cCif~up  ,*nJ*  pAr^eloJ 

Fig.  611.    Steel  Supports  for  Masonry,    Incorrect  and  Correct  Methods. 


Fig.  612.     Steel  Supports  for  Masonry.     Incorrect  and  Correct  Methods. 


764 


BUILDING 


CONSTRUCTION, 


(Ch.  XI) 


Fig.  611  shows  metal  supports  formed  by  channels,  angles, 
anchors,  hook-bolts  and  plates  as  indicated.  The  figure  on  the  left 
shows  the  incorrect  method  of  constructing  a  wide  terra-cotta  soffit, 
that  is,  in  making  it  in  one  piece.  The  figure  on  the  right  shows  the 
correct  method,  the  one  in  which  the  wide  soffit  is  cut  up  into  more 
than  one  piece,  three  pieces  in  this  case,  in  order  to  insure  a  perfect 
alignment  when  the  pieces  shrink  unequally.  The  method  of  sup- 
port is  clearly  shown  in  the  drawing. 

Fig.  612  shows  incorrect  and  correct  methods  of  supporting 
terra-cotta  lintels  by  metal  supports  in  cases  in  which  there  is  a  ten- 
dency to  break  off  a  portion  of  the  terra-cotta  lintel  by  some  settle- 
ment of  the  metal  supports.  The  drawing  on  the  left  shows  the  in- 
correct method  of  construction  in  which  the  lintel  is  supported  on 
an  angle  which  comes  close  to  its  face.  The  slightest  settlement 
v/ill  cause  the  staff-bead  to  press  up  against  the  terra-cotta  and  break 
it  off  as  shown.  In  the  drawing  on  the  right  the  angle  is  shown 
with  horizontal  leg  made  much  shorter,  as  shown  by  the  distance 
*'A,"  the  danger  of  breaking  the  terra-cotta  being  thus  considerably 
less,* 

642.  STEEL  SUPPORTS  FOR  CORNICES.— In  any  dis- 
cussion of  the  iron  and  steel  supports  for  masonwork  the  subject 
of  the  metal  supports  for  cornices  of  stone  or  terra-cotta  should  be 
referred  to  with  at  least  one  general  type  of  support  given  in  illus- 
tration. Terra-cotta  and  stone  cornices  vary  so  much  in  profile, 
height  and  projection  that  many  variations  could  be  shown  in  the 
way  of  metal  supports.  In  this  connection  the  reader  is  referred 
to  the  many  illustrations  of  terra-cotta  cornice  construction  given  in 
Chapter  VHI,  on  "Architectural  Terra-cotta,"  as  these  illustrations 
include  the  steel  supports. 

One  additional  illustration  of  steel  supports  for  terra-cotta  cornice 
work  is  given  here,  and  reproduced  through  the  courtesy  of  The 
Brickbiiildcr,  which  contains  in  its  various  issues  many  excellent 
examples. 

Fig.  613  shows  the  metal  support  for  the  terra-cotta  cornice  of 
the  Chamber  of  Commerce  building,  in  Rochester,  N.  Y.,  Nolan, 
Nolan  &  Stern,  architects. f 

*  See  also  the  ntnncrons  HluFtrations  of  steel  and  iron  supports  for  masonry  in 
Chapter  VIII,  "Architectural  Terra-cotta,"  shown  in  connection  with  terra-cotta  con- 
struction. 

t  For  full  clescri])tions  of  many  architectural  terra-cotta  constructions  and  their  metal 
supports,  see  series  of  articles  in  Tlic  Brickbiiildcr  for  1897-98.  and  in  still  more  recent 
issues,  by  Mr.  Thomas  Cusack,  from  whose  descriptions  the  above  is  taken. 


CORNICE  SUPPORTS. 


7^5 


This  cornice  is  8  feet  9  inches  high,  and,  having  a  total  projection 
of  5  feet  from  wall  line  to  nose  of  lion's  head,  requires  a  well-devised 
scheme  of  structural  support.  The  one  that  was  adopted  is  shown 
in  detail  in  Fig.  613.  To  the  Z-bar  columns  that  extend  up  through 
the  piers  is  bracketed,  horizontally,  a  lo-inch  I-beam.  This  acts  as 
a  fulcrum  for  a  series  of  6-inch  I-beams  that  project  over  each 
modillion,  the  opposite  ends  being  attached  to  roof  beams  by  means 


Fig.  613.     Steel  Supports  for  Terra-cotta  Cornice.     Chamber  of  Commerce  Jkiilding, 

Rochester,  N.  Y. 


of  stirrups.  These  cantilevers,  in  addition  to  the  weight  that 
rests  on  top  of  them,  are  strong  enough  to  support  the  modillions 
also.  This  they  are  made  to  do  by  the  application  of  two  ^-inch 
hangers,  which,  taking  hold  of  a  short  bar  inserted  in  each  modillion, 
pass  up  through  a  plate  laid  across  each  cantilever,  where  they  are 
tightened  up  to  the  required  tension.  The  dentil  course  and  the 
panels  between  modillions  have  each  a  series  of  holes  through  which 
rods  are  passed,  and  around  which  anchors  hook  and  run  back 
through  the  wall. 

The  modillions  are  spaced  3  feet  8  inches  on  centers.  This  made 
it  inadvisable  to  design  the  soffit  blocks  in  single  pieces.  They  are 
therefore  divided  into  three  pieces  for  greater  convenience  in  hand- 


766 


BUILDING  CONSTRUCTION.  (Ch.  XI) 


ling  and  setting,  as  well  as  in  making.  This  allows  the  two  side 
pieces  to  be  fitted  into  the  flanges  and  bedded  down  to  each  side 
of  the  cantilever.  The  middle  piece,  to  which  the  coffer  panel  is 
attached,  is  then  dropped  in  as  a  key,  and  the  whole  course  is  thus 
made  immovable.  A  hole  is  provided  in  the  blocks  forming  the 
cvmatium,  into  which  short  pieces  of  round  iron  are  inserted,  and 


1^ 


Fig.  614.     Bay-window  Supports. 


 Ji/i"  i  ^ 

Wyandotte  Building,  Columbus,  Ohio. 


from  these  diagonal  braces  are  run  at  intervals  and  rivetted  to  the 
6-inch  I-beams,  as  indicated  in  the  section.  The  top  surface  of 
this  cornice  is  covered  with  copper. 

643.  BAY-WINDOWS  IN  SKELETON  CONSTRUCTION. 
■ — (See  also  Article  638.)  These  have  become  very  prominent  fea- 
tures in  the  modern  office-buildings  and  hotels.  In  skeleton  buildings 
the  masonwork  of  the  bays  is  made  as  light  as  possible,  with  slender 


BAY-WINDOW  SUPPORTS. 


terra-cotta  mullions  and  angles,  and  is  supported  in  each  story  by 
brackets  built  out  from  the  spandrel  beams  or  girders,  as  shown  in 
Figs.  614  and  615,  which  are  sections  from  the  Wyandotte  build- 
ing, Columbus,  Ohio. 


Fig.   616.     Plan   of  Piers  and  Mullions  in  Alley  and  Light-court, 
New  York  Life  Building,  Chicago. 

As  the  leverage  on  these  brackets  is  considerable,  they  should  be 
securely  rivetted  to  the  spandrel  beams,  and  the  latter  well  tied  or 
framed  to  the  floor  construction  to  keep  them  from  twisting. 


768 


BUILDING  CONSTRUCTION. 


(Ch..  XI) 


Where  mnllions  occur  between  window^,  and  at  the  angles  of  the 
bays,  cast-iron  or  steel  angles  or  T-bars  are  bolted  or  rivetted  to  the 
metalwork  above  and  below,  to  stay  the  frames  and  terra-cotta 
mullions  and  angles,  in  the  manner  shown  in  Fig.  6i6. 

644.  WALL  COLUMNS. — The  importance  of  thoroughly  fire- 
proofing  the  exterior  columns  has  already  been  considered  in  Chap- 
ter IX.  Fig.  616,  however,  is  given  as  one  example  of  pier  con- 
struction in  some  Chicago  buildings. 

Further  illustrations  of  the  manner  of  supporting  the  masonwork 
in  this  class  of  buildings  may  be  found  in  "Architectural  Engineer- 
ing," by  Joseph  K.  Freitag,  C.  E.,  and  in  many  numbers  of  The 
Eiigijiecring  Record^nd  of  The  Brickbiiildcr. 


645.  MISCELLANEOUS  IRONWORK.— The  following  de- 
tails of  ironwork  used  in  connection  with  brickwork  and  stonework 
should  perhaps  be  mentioned  here,  as  they  have  to  be  considered 
when  designing  the  masonwork. 

Bearing-plates. — Wherever  iron  or  wooden  posts,  columns  or 
girders  rest  on  brickwork,  a  cast-iron  or  stone  bearing-plate  should 
be  used  to  distribute  the  concentrated  weight  over  a  safe  area  of  the 
masonwork.  Several  failures  in  buildings  have  resulted  from  care- 
lessness in  this  particular.  Rules  for  proportioning  the  size  of  bear- 
ing-plates are  given  in  the  "Architect's  and  Builder's  Pocket- 
Book,"  by  Frank  E.  Kidder. 

Cast-iron  Skewbacks  for  Brick  Arches. — Whatever  segmental 


Fig.    617.      Cast-iron    Skewback  for 
Brick  Arch. 


Fig.  618.    Cast-iron  Shutter-eyes. 

a.  Form    for    Brick  Walls. 

b.  Form    for    Stone  Walls. 


MISCELLANEOUS  IRONWORK.  769 


arches  are  used  over  doors  of  windows,  without  ample  abutments, 
cast-iron  skewbacks,  connected  by  iron  rods  of  proper  size,  should 
be  used  to  take  up  the  thrust  of  the  arch,  as  shown  in  Fig.  617. 

Shutter-eyes. — All  fire-proof  doors  and  shutters  in  brick  or  stone 
walls  should  have  hinges  made  of  2-inch  by  ^-inch  flat  iron  bars, 
welded  around  a  %-inch  diameter  pin  working  in  a  cast-iron  shutter- 
eye  built  into  the  wall.  For  brick  walls  the  shape  shown  at  a,  Fig. 
618,  is  about  the  best  for  the  eyes,  although  for  very  heavy  doors 
or  shutters  the  strength  of  the  face  should  be  increased  by  the 
addition  of  another  web.  For  stone  walls  the  shape  shown  at  b 
should  be  used.  The  thickness  of  the  metal  is  generally  made  34 
•of  an  inch.  * 


n 

Fig.  619.    Iron  Wheel-guard.     Alley  Pier,  New  York 
Life  Building,  Chicago. 

Door-guards  and  Bumpers. — It  is  a  good  idea  to  protect  the 
brick  jambs  of  the  carriage  doors  in  stables  by  bumpers,  which  are 
rounded  projections  on  the  corners,  extending  a  distance  of  from 
12  to  18  inches  above  the  ground  and  to  a  point  about  8  inches 
beyond  or  in  front  of  the  wall  and  the  jambs,  so  that  if  a  carriage 
wheel  strikes  the  bumper  the  hub  will  not  scratch  the  brick  jambs. 
Such  bumpers  may  be  made  either  of  some  hard  stone  or  of  iron. 
The  jambs  of  the  outside  doorways  to  freight  elevators  also,  and 
of  the  delivery  and  receiving  doorways  in  mercantile  buildings, 
should  be  protected  to  a  height  of  4  or  5  feet  above  the  sills  by 
iron  guards,  to  prevent  the  brickwork  being  broken  by  boxes, 
trucks,  -etc.    Such  guards  are  generally  made  of  cast-iron  about 


770 


BUILDING  CONSTRUCTION.  (Ch.  XI> 


y2  of  an  inch  thick,  as  it  is  easier  to  fasten  castings  to  a  wall  than 
it  is  to  fasten  plate-iron.  The  castings,  or  plates,  should  be  made 
with  lugs  on  the  inside  pierced  with  holes  for  clamping  them, 
securely  to  the  brickwork  as  the  wall  is  built.    Fig.  619  shows  a 

section  of  one  of  the 
alley  piers  of  the  New 
York  Life  building,  Chi- 
cago, and  the  manner 
in  w^hich  the  iron  guards 
are  attached  to  the  brick- 
work.  A  similar  ar- 
rangement   can  be 

Fig,    620.     Cast-iron    Chimney  Cap.     Common    Form,    adapted     tO     any  doOr 

jamb.  It  is  quite  common  to  protect  the  bottoms  of  the  piers 
on  the  alleys  in  this  way  to  prevent  injury  to  the  walls  from  pass- 
ing teams. 

Chimney  Caps. — For  many  kinds  of  tall  brick  chimneys  cast-iron, 
caps  are  generally  considered  durable  finishes  for  the  top.  A 
common  form  for  such  caps  is  that  shown  in  Fig.  620.  Such  a. 
cap  completely  protects  the  mortar  joints 
from  the  weather  and  prevents  the  bricks 
in  the  upper  courses  from  becoming 
loose.  If  the  chimney  is  corbelled  out  as 
shown  the  cap  acts  also  as  a  drip  to  pro- 
tect its  sides,  or  at  least  thtir  upper  parts. 
The  inner  lip  of  the  cap  should  extend 
down  into  the  chimney  a  distance  of 
from  8  to  12  inches.  If  the  cap  is  not 
more  than  4  feet  square  it  need  not  be 
thicker  than  34  of  ii^ch ;  but  if  it  is 
larger  than  this  the  thickness  should  be 
increased  to  }i  of  an  inch. 

If  the  cap  is  3  feet  or  more  square, 
for  convenience  in  handling  it  should  be 
cast   in   two   or   four   sections,  which 
should  be  bolted  together,  flanges  being  cast  on  the  under  side  for 
this  purpose. 

Chimney  Ladders. — It  is  sometimes  desirable  to  have  ladders 
built  on  the  inside  of  large  brick  flues  or  shafts  and  on  the  out- 
side of  tall  chimneys,  to  serve  as  ready  means  of  reaching  the  top. 


1 


1 — r 


Front 


Fig.  6i 


Chimney  Ladder. 


MISCELLAXEOUS  HIOXIVORK. 


771 


Such  ladders  are  usually  made  of  ^)i;-inch  round  iron  bars,  bent 
to  the  shape  shown  in  Fig.  621,  and  placed  in  the  wall  of  a  chimney, 
or  flue,  as  it  is  built.  For  easy  climbing  the  rungs  should  be  placed 
12  inches  on  centers,  and  they  should  be  about  18  inches  wide,  with 
a  projection  of  about  6  inches  out  from  the  wall. 

Coal-hole  Covers  and  Frames. — When  coal  vaults  are  placed 
under  a  sidewalk  the  architect  should  specify  iron  frames  and 
covers  for  the  holes  made  for  putting  in  the  coal.  If  a  vault  is 
covered  with  granite  flagging  a  rebate  may  be  cut  in  the  stone  to 
receive  the  cover,  in  which  case  no  frame  is  necessary.  In  stones 
of  all  other  kinds,  and  in  cement  walks,  the  holes  should  be  pro- 
tected by  a  cast-iron  frame  at  least  4  inches  deep.  A  frame  of  this 
kind  is  generally  cast  with  a  projecting  ring  about  2  inches  wide 
and  of  an  inch  thick,  which  should  be  set  in  a  rebate  cut  in  the 
stone  and  filled  with  soft  Portland  cement.  It  is  made  also  with  a 
^-inch  rebate  for  the  iron  cover,  which  is  made  of  cast-iron  about 
y2  of  an  inch  thick  and  with  a  roughened  top  surface.  These  covers 
are  sometimes  made  with  holes,  into  which  glass  bull's-eyes  are 
cemented  in  order  to  admit  light  to  the  vault.  Both  solid  and 
glazed  covers  are  generally  carried  in  stock  by  the  larger  iron 
foundries,  and  in  sizes  varying  from  16  to  24  inches  in  diameter. 


Chapter  XIL 

Lathing  and  Plastering, 


646.  GENERAL  CONSIDERATIONS.— Probably  99  per  cent 
of  modern  buildings,  in  this  country,  at  least,  have  plastered  walls, 
ceilings  and  partitions.  It  is  only  lately,  however,  that  much 
attention  has  been  given  to  this  branch  of  building  operations,  and 
it  is  doubtless  true  that  much  of  the  plastering  done  at  the  present 
day  is  inferior  to  that  done  fifty  or  one  hundred  years  ago. 

The  introduction  of  fire-proof  construction  and  the  desirability  of 
completing  large  and  costly  commercial  buildings  in  the  shortest 
possible  time  have  shown  the  necessity  for  improvements  in  the 
materials  used  both  for  lathing  and  plastering,  and  several  new 
materials  have  been  introduced  to  meet  these  demands. 

Even  in  dwellings  it  is  important  to  have  the  finish  of  walls  and 
ceilings  as  nearly  perfect  as  possible,  as  large  sums  of  money  are 
not  infrequently  spent  on  their  decoration ;  and  it  is  therefore 
essential  that  the  groundwork  shall  be  so  durable  that  the  decora- 
tions will  not  be  ruined  by  broken  walls  or  falling  ceilings.  The 
quality  of  the  workmanship  is  also  of  much  importance,  as  nothing 
mars  the  appearance  of  a  room  more  than  crooked  walls  and  angles, 
and  dents,  cracks  and  patches  in  the  plastering. 

To  secure  a  good  job  of  lathing  and  plastering  it  is  essential  that 
only  the  best  materials  be  specified  and  used,  and  that  the  mortar 
be  properly  prepared  and  applied.  Good  results  are  obtained  only 
by  carefully  specifying  exactly  how  the  work  is  to  be  done  and 
what  materials  are  to  be  used,  and  by  supplementing  these  specifi- 
cations by  efficient  supervision.  In  order  to  furnish  such  specifica- 
tions and  superintendence  it  is  obviously  necessary  that  the  archi- 
tect shall  be  thoroughly  familiar  with  the  materials  used  and  with 
the  way  in  wdiich  they  should  be  applied. 

Brick,  tile  and  concrete  walls,  ceilings  and  partitions  do  not 
require  lathing,  as  the  plastering  may  be  applied  to  them  directly, 
these  materials  having  an  affinity  for  the  mortar  which,  is  held 


772 


LATH IX G  AND  PLASTERING. 


773 


•securely  in  place.  Other  constructions  require  some  form  of  lathing 
to  serve  as  a  ground  to  receive  and  hold  the  plaster. 

647.  WOODEN  Lx\THS.— Practically  all  dwellings  of  mod- 
crate  cost,  and  a  large  proportion  of  other  buildings,  are  still  lathed 
with  wooden  laths ;  and  if  of  good  quality  they  give  very  satisfac- 
tory results  where  no  fire-proof  properties  are  expected.  It  is  gen- 
erally admitted  that  the  best  wood  for  laths  is  white  pine,  although 
nearly  as  many  are  made  of  spruce,  which  answers  very  well.  Hard 
pine  is  not  a  good  material  for  laths,  as  it  contains  too  much 
pitch; 

Wooden  laths  should  be  well  seasoned  and  free  from  sap,  bark 
and  dead  knots.  Small  sound  knots  are  not  particularly  objection- 
able. Bark  is  often  found  on  the  edges  of  laths,  and  is  probably 
the  greatest  defect  found  in  them,  as  it  is  quite  sure  to  stain 
through  the  plaster. 

The  usual  dimensions  of  wooden  laths  are  /4  by  1^4  inches  in 
cross-section  and  4  feet  in  length ;  the  width  and  thickness  vary 
somewhat  in  dififerent  mills,  but  the  length  is  always  the  same.  The 
studding  or  furring  strips  should  therefore  be  spaced  either  12  or 
16  inches  apart  on  centers;  12-inch  spacing  gives  five  nailings  and 
16-inch  spacing  four  nailings  to  a  lath. 

The  former  obviously  makes  the  stronger  and  better  wall.  It  is 
particularly  desirable  that  laths  on  ceilings  have  five  nailings,  as 
there  is  a  greater  pull  on  them  than  on  those  on  the  walls. 

648.  SHEATHING  LATH.— Combination  sheathing  and  lath, 
such  as  the  Byrkit-Hall  sheathing  lath,  has  been  on  the  market 

for  many  years.  It  is  made  by  special  machinery 
from  pine,  hemlock,  cypress  and  poplar,  in  the 
same  lengths  as  flooring  and  in  4-,  6-  and  8-inch 
widths,  the  edges  being  either  tongued  and  grooved 
or  square.  The  general  form  of  the  lath  is  shown 
in  Fig.  622. 

When  used  on  the  outside  of  frame  walls  it 
answers  the  purpose  of  sheathing,  and  also  forms 
a  clinch  for  back-plastering  on  the  inside. 
Fig.  622.  Byrkit-Haii     For    stuccowork.    Staff,  plastcr-of-Paris  orna- 
Sheathing  Lath.     nicntatious   and  imitations  of   stone,   it  can  be 
placed  with  the  grooved  side  out,  to  receive  the  mortar. 

Thirty  million  feet  of  this  lath  were  used  on  the  Columbian  Expo- 


774 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


sition  buildings  in  1892  and  1893;  twelve  million  feet  on  the  Pan- 
American  Exposition  buildings  and  about  thirty  million  feet  on  the 
Exposition  buildings  at  St.  Louis,  Mo.  In  the  North,  Northwest 
and  Middle  States  this  lath  has  been  extensively  used  for  rough- 
cast work,  back-plastering  and  interior  lathing. 

649.  METAL  LATH. — The  different  kinds  of  metal  lath  are 
classified  in  Article  479  and  described  in  detail  with  illustrations  in 
the  succeeding  articles  in  Chapter  IX. 

At  about  the  same  time  that  the  interest  in  fire-proof  construction 
became  more  general,  wire  netting  came  into  use  as  a  substitute  for 
wooden  laths.  It  was  found  that  the  strands  of  the  netting  became 
completely  imbedded  in  the  plaster  and  held  it  so  securely  that  it 
could  not  become  detached  by  any  ordinary  accidents.  It  was  found 
also  that  the  plaster  protects  the  wire  from  heat,  and  that  the  body 
of  the  metal  is  so  small  that  it  has  no  appreciable  expansion  when 
subjected  to  fire. 

Plasters  on  metal  lath,  and  particularly  hard  plasters,  will  protect 
woodwork  from  a  severe  fire  as  long  as  the  plasters  remain  intact,  • 
provided  there  are  no  cracks  or  loopholes  at  the  corners  and  around 
columns  where  the  fire  can  get  through. 

Objection  has  been  made  to  the  ordinary  wire  lath  that  it  is  diffi- 
cult to  stretch  it  so  tight  that  it  will  not  yield  to  the  pressure  exerted 
in  applying  several  coats  of  mortar.  Another  objection,  and  one  that 
is  made  to  the  use  of  expanded-metal  lath  also,  is  that  they  both 
take  a  great  deal  of  plaster.  From  the  standpoint  of  first  cost 
this  is  undoubtedly  a  valid  objection;  but  from  the  standpoint 
of  fire-resistance  the  great  amount  of  mortar  used  is  its  greatest 
recommendation.  It  should  be  remembered  that  the  mortar,  and 
not  the  metal,  is  the  fire-resisting  part  of  a  wall  or  ceiling.  No 
metal  lath,  the  author  believes,  should  be  considered  fire-proof  which 
does  not,  in  use,  become  imbedded  in  the  mortar;  for  if  the  thin 
coating  of  plaster  peels  off  many  kinds  of  metal  lath  will  resist 
the  fire  no  better  than  will  the  wooden  laths  and  will  be  more  in 
the  way  of  the  fireman. 

Wire  lathing  is  now  made  in  great  variety  to  meet  the  require- 
ments of  the  different  plaster  compositions  and  the  varying  con- 
ditions of  construction. 

In  order  to  properly  protect  wooden  construction,  such  as  beams, 
posts,  studding  or  planks,  from  fire  by  means  of  wire  lath  and 


LATHING  AND  PLASTERING. 


77S 


plaster,  it  is  essential  that  the  lath  be  kept  at  least  }i  of  an  inch 
away  from  the  woodwork  by  iron  furring  of  some  form.  A  i-inch 
space  is  still  better.  This  setting  off  of  the  lath  from  the  wood  is 
generally  done  either  by  means  of  bars  woven  into  or  attached  to 
the  lathing,  or  by  means  of  iron  furring  put  up  in  advance  of  the 
lathing.  The  various  methods  of  furring  are  described  in  Articles 
480  to  483,  in  connection  with  the  description  of  the  different  metal 
laths  themselves ;  and  metal  wall  furring  and  furring  for  archi- 
tectural forms  are  described  in  Articles  486  and  487. 

When  using  common  lime  mortar  on  metal  lath  the  first  coat 
should  be  gauged  with  plaster  of  Paris.  Painted,  galvanized  or 
japanned  lath  should  always  be  used  for  hard  plasters  which  are 
made  by  chemical  processes. 

Aside  from  their  fire-resisting  qualities,  wire  laths  or  metal 
laths  possess  these  advantages :  plastering  applied  to  them  does  not 
crack  from  the  shrinkage  of  woodwork  and  the  plaster  does  not 
fall  off.  If  the  lathing  is  set  away  from  the  wood  studding  the 
location  of  the  timbers  is  not  shown  by  the  plaster,  as  is  often  the 
case  after  a  few  years  when  wooden  laths  are  used.  Metal  laths 
are  also  proof  against  rats  and  mice,  a  property  which  makes  them 
especially  desirable  in  certain  kinds  of  store  buildings.  Many  of 
these  advantages  are  lost,  however,  when  unstiffened  wire  cloth  is 
stretched  over  wood  furrings. 

650.  WALL-BOARDS  AND  PLASTER-BOARDS.  —  Thin 
boards  made  of  plaster  and  reeds  of  fiber  have  been  quite  exten- 
sively used,  not  exactly  as  laths,  but  as  a  ground  for  the  second 
and  third  coats  of  plaster.  They  are  made  in  slabs  of  varying 
lengths,  widths  and  thicknesses. 

For  a  general  description  of  wall-boards  and  plaster-boards  see 
Article  470,  included  in  the  description  of  plaster-block  and  wall- 
board  partitions. 

The  boards  can  be  sawed  into  any  size  or  shape  and  nailed 
directly  to  the  under  side  of  the  joists  or  to  studding  or  furring. 
They  are  rapidly  put  on  and  require  no  scratch  coat,  and  with  some 
styles  of  boards  a  white  or  finished  coat  is  all  that  is  necessary. 

On  account  of  their  lightness,  and  the  ease  with  which  they  can 
be  cut,  they  are  sometimes  preferred  to  tile  or  terra-cotta  for 
suspended  ceilings  under  iron  beams. 

Owing  to  the  saving  of  plaster,  the  low  cost  of  the  boards  and 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


the  ease  with  which  they  are  put  up,  plaster-boards  have  been  used 
to  a  considerable  extent  in  some  parts  of  the  country. 

In  using  plaster-boards,  or  any  of  the  patented  laths,  the  architect 
or  builder  should  follow  the  directions  of  the  manufacturers  as  to 
the  manner  of  putting  in  place,  etc.,  as  there  are  often  important 
precautions  which  might  otherwise  be  overlooked. 

651.  WHERE  METAL  LATH  SHOULD  BE  USED.— It  is 
of  course  desirable  that  metal  lath  or  plaster-boards  should  be  used 
wherever  any  lathing  is  required,  but  the  increased  expense  gen- 
erally prevents  their  use  in  the  majority  of  buildings. 

There  are,  however,  many  places  where  metal  lath  is  particularly 
desirable,  especially  in  buildings  having  ordinary  w^ood  floors  and 
partitions.  Such  places  are  the  under  side  of  stairs  in  public  build- 
ings, the  ceilings  in  audience  and  assembly-rooms,  the  under  side 
of  galleries,  the  ceilings  of  boiler-rooms,  furnace-rooms,  etc. 

Metal  lath  should  be  used  also  on  both  sides  of  hot-air  pipes  in 
wood  partitions.  Where  there  are  slots  in  brick  walls  for  plumb- 
ing pipes,  hot-air  pipes  or  steam  pipes,  they  should  be  covered  with 
metal  lath,  unless  the  walls  are  furred  or  the  recesses  cased  with 
boards. 

Metal  lath  should  be  used  also  at  the  joining  of  wood  partitions 
and  brick  walls  when  the  walls  are  not  furred ;  and  particularly 
when  the  partition  is  parallel  and  flush  with  the  wall. 

By  using  a  strip  of  wire  lath  or  expanded-metal,  lapped  12  inches 
on  the  wall  and  partition,  a  crack  at  the  juncture  of  the  two  will 
be  avoided,  and  at  only  a  very  slight  additional  expense. 

It  very  often  happens  in  outside  brick  walls  that  the  arched 
wooden  lintels  over  the  windows  come  partly  above  the  casing,  and 
if  the  wall  is  plastered  directly  on  the  brickwork  the  plastering  gen- 
erally cracks  over  the  lintel,  or  does  not  stick  to  it.  This  can  be 
avoided  by  covering  the  lintel  with  a  strip  of  metal  lath,  lapped 
6  or  more  inches  on  the  brickwork. 

In  general,  wherever  solid  timber  has  to  be  plastered,  and  where 
there  is  no  room  for  furring  and  lathing,  it  should  be  covered  with 
metal  lath,  which  should  also  be  lapped  well  on  the  adjoining  par- 
tition or  wall. 

652.  INTERIOR  PLASTERING.— The  very  general  practice 
of  plastering  walls  and  ceilings  dates  back  not  much  more  than  a 
century.    Previous  to  that  time  the  walls  and  ceilings  were  wain- 


LATHING  AND  PLASTERING. 


777. 


scoted,  boarded  covered  with  canvas  or  tapestries  or  else  left  rough. 

On  account  of  its  cheapness,  its  fire-resisting  and  deafening  qual- 
ities, and  its  adaptability  to  decorative  treatment,  some  kind  of 
plastering  will  probably  always  be  used  for  finishing  the  interior 
walls  and  ceilings  of  buildings. 

In  describing  plastering  operations  it  will  be  more  convenient  to 
consider  the  subject  under  the  headings:  "Lime  Plaster,"  "Hard  or 
Cement  Plaster,"  ''Interior  Stuccowork"  and  "Exterior  Plastering/' 

653.  LIME  PLASTER.— Up  to  about  the  year  1885  all  interior 
plastering  used  in  this  country  was  made  of  quicklime,  sand  and 
hair. 

There  can  be  no  question  but  that  plaster  made  of  a  good  quality 
of  lime,  thoroughly  slaked  and  mixed  in  the  proper  manner,  is  very 
durable  and  also  a  valuable  sanitary  agent.  Most  of  the  lime 
plaster  used  at  the  present  day,  however,  is  very  poorly  and  cheaply 
made,  often  of  poor  materials,  and  very  much  of  it  far  from 
durable. 

The  stones  from  which  lime  is  made,  the  characteristics  of  good 
lime,  the  methods  of  slaking  and  making  into  mortar,  hydrated  lime, 
the  sand  used  in  lime  mortar,  the  setting  and  durability  of  lime 
mortar,  etc.,  are  fully  discussed  in  Articles  145  to  153. 

While  the  mortar  considered  in  these  articles  is  for  laying  up 
masonry,  the  statements  made  relate  also  generally,  with  some  few 
exceptions,  to  mortar  for  plastering. 

There  are  some  limes  which,  while  good  enough  for  making  ordi- 
nary mortar  for  masonry,  are  not  suitable  for  making  plaster ;  this 
is  because  all  the .  particles  of  the  lime  do  not  immediately  slake. 
Some  of  the  particles,  because  they  are  overburned  or  for  some 
other  reason,  do  not  slake  with  the  bulk  of  the  lime,  but  continue 
to  absorb  moisture ;  and  finally,  after  a  long  period,  extending 
sometimes  over  two  years,  they  slake  or  ''pop"  and  cause  bits  of 
plaster  to  fall  off. 

The  author  has  seen  walls  and  ceilings  that  w^ere  pitted  all  over 
from  this  cause. 

It  is  therefore  important  that  the  architect,  when  building  in 
a  new  locality,  or  upon  commencing  his  practice,  should  make 
inquiries  as  to  the  slaking  qualities  of  the  lime  at  hand ;  and,  where 
more  than  one  lime  is  available,  as  to  which  one  is  the  best.  In 
some  localities  four  or  five  different  qualities  of  lime,  from  as  m^y 


7/8 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


different  places,  are  found  on  the  market ;  and  in  such  cases  the 
architect  should  be  very  careful  to  specify  that  particular  lime 
which  he  considers  the  best.  Limes  are  generally  known  by  the 
name  of  the  locality  in  which  the  rocks  are  quarried.  Even  in  the 
best  limes  some  particles  do  not  slake  quite  as  quickly  as  others, 
and  it  is  not  generally  safe  to  apply  any  plastering  in  which  the 
lime  has  not  been  slaked  from  ten  days  to  two  weeks. 

The  usual  specifications  for  sand  used  in  making  mortar  for 
plastering  require  that  it  shall  be  angular,  not  too  coarse  nor  too 
fine  and  free  from  dust  and  all  foreign  substances.  Methods  of 
testing  sand  for  foreign  substances  and  conclusions  reached  from 
recent  tests  and  experiments  are  discussed  in  Article  149. 

For  the  very  best  plaster  the  sand  should  be  screened,  zvashed 
and  dried.  Sand  prepared  in  this  way  can  sometimes  be  obtained 
in  the  larger  cities,  but  in  most  work  it  is  merely  screened. 

Sea  sand  is  less  angular  than  other  sands,  and  is  also  considered 
objectionable  on  account  of  the  salt  contained  in  it.  It  should 
never  be  used  unless  thoroughly  washed  in  fresh  water.  All  sands 
used  in  plastering  mortar  require  careful  screening  to  take  out  the 
coarse  particles  ;  and  sand  for  hard  finish  should  be  passed  through 
a  sieve. 

Although  the  principal  use  of  sand  in  mortar  is  to  prevent 
shrinking  and  to  reduce  the  quantity  of  lime,  it  is  considered  by 
some,  but  not  by  all,  authorities  to  result  also  in  a  valuable  chemical 
action  and  in  the  formation  of  a  hard  silicate  of  lime,  which  per- 
vades and  strengthens  the  plaster.     (See  Article  151.) 

In  order  to  make  the  coarse  plaster  hang  together  better,  hair  or 
fiber  should  be  mixed  with  the  mortar  for  the  groundwork. 

Outside  of  a  few  of  the  large  Eastern  cities  hair  has  been  largely 
used  for  this  purpose.  For  several  years  Manila  fiber,  chopped 
into  lengths  of  about  2  inches,  has  been  used  instead  of  hair  for 
ordinary  mortar  in  some  cities,  especially  in  the  East.  Most  of 
the  patent  mortars  contain  either  asbestos  or  fiber.  Fiber  is  cleaner 
than  hair  and  is  said  to  be  less  injured  by. the  lime. 

I\Iost  of  the  hair  used  by  plasterers  is  taken  from  the  hides  of 
cattle,  and  is  washed  and  dried  and  put  up  in  paper  bags,  each  bag 
being  supposed  to  contain  one  bushel  of  hair  after  it  is  beaten  up. 

The  weight  is  generally  given  as  7  or  8  pounds,  but  it  often 
falls  much  short  of  this. 


LATHING  AND  PLASTERING. 


779 


If  obtained  from  a  local  tannery,  the  hair  should  be  thoroughly 
washed  and  separated  before  using. 

Hair  is  generally  described  in  the  specifications  as  "best  quality 
clean,  long  cattle  hair,"  but  the  plasterer  must  take  it  as  it  comes 
in  the  bags. 

Goat  hair  has  been  used  to  some  extent  in  the  Eastern  States. 
It  is  longer  and  of  a  better  quality  than  cattle  hair. 

654.  MIXING  MORTAR  FOR  PLASTERING.— The  proper 
mixing  of  lime  mortar  comes  next  in  importance  to  the  quality  of 
the  lime.  The  tendency  to  reduce  the  cost  of  building  to  the  lowest 
possible  point,  and  to  shorten  the  time  required  for  the  various 
operations,  has,  with  other  influences,  led  to  much  neglect  in  the 
mixing  of  mortar ;  and  it  is  safe  to  say  that  three-quarters  of  the 
lime  plaster  used  at  the  present  time  is  not  properly  mixed. 

Where  mortar  is  mixed  by  hand  at  rhe  site  of  the  building,  the 
following  method  is  probably  the  best  that  can  be  considered  as 
practicable : 

First,  the  lime  should  be  thoroughly  slaked  in  a  tight  box,  or, 
if  the  lime  is  not  pure,  and  a  residue  is  left  after  slaking,  it  should 
be  run  off  through  a  wire  sieve  into  another  box  and  allowed  to 
stand  for  from  twenty-four  hours  to  seven  days. 

Secondly,  after  the  lime  has  been  slaked  the  required  length  of 
time,  the  hair  should  be  beaten  up  and  thoroughly  incorporated  with 
the  lime  paste  by  means  of  a  hoe.  The  proper  afnount  of  sand 
should  then  be  added  and  the  mixture  heaped  up  in  a  pile. 

Thirdly,  after  the  mortar  has  stood  in  the  pile  not  less  than  seven 
clays,  it  should  be  wet  up  in  small  quantities  to  the  proper  con- 
sistency and  immediately  applied  to  the  lathing,  brickwork  or  other 
masonry  surface. 

The  ordinary  method  of  mixing  plastering  mortar  is  to, mix  the 
hair  and  sand  with  the  lime  as  soon  as  it  is  slaked,  and  then  to 
throw  the  mortar  in  a  pile,  the  whole  process  occupying  but  one 
or  two  hours.  The  objection  to  this  method  is  that  the  lime  is  not 
always  thoroughly  slaked,  and  that  the  hot  lime  and  the  steam 
caused  by  the  slaking  burn  or  rot  the  hair  so  as  almost  to  destroy 
its  function,  that  of  strengthening  the  plaster.  For  all  good  work 
the  architect  should  specify  that  the  lime  be  slaked  at  least  twenty- 
four  hours  before  the  working  in  of  the  hair. 

For  United  States  Government  work  the  hair  is  not  mixed  in 


78o 


BUILDING  CONSTRUCTION.        (Ch.  Xll);, 


until  the  mortar  is  wet  up  for  putting  on.  This  is  a  still  better,, 
but  a  rather  more  expensive  method. 

If  the  mortar  is  required  for  use  in  freezing  weather  it  should 
be  made  under  cover ;  and  under  no  circumstances  should  the  archi- 
tect permit  the  use  of  mortar  that  has  been  frozen. 

The  mixing  of  mortar  in  basements,  although  sometimes  found 
necessary,  is  not  desirable,  as  it  introduces  much  moisture  into  a 
building.  Mortar  should  never  be  made  in  a  building  when  it  is. 
practicable  to  avoid  it. 

655.  MACHINE-MADE  MORTAR.— In  some  cities  mortar, 
for  both  masonwork  and  plastering,  is  made  by  machinery  in  build-- 
ings  specially  arranged  for  the  purpose,  and  delivered  at  the  work 
in  cartloads  in  a  wet  and  plastic  condition,  with  the  hair  or  fiber, 
and  fresh  water  incorporated  with  the  lime  and  sand,  ready  for 
use,  without  the  addition  of  any  other  material  or  further  manipu- 
lation. 

The  advantages  of  having  the  mortar  made  in  this  way  are  that 
ample  time  is  given  the  lime  to  slake,  the  hair  and  sand  are  not 
mixed  with  the  lime  until  just  before  delivery  and  the  mixing  is 
much  more  thoroughly  and  evenly  done  by  machinery  than  is 
possible  by  hand. 

Using  mortar  mixed  at  some  other  place  than  in  the  building- 
permits  of  finishing  the  lower  stories  sooner  than  could  otherwise 
be  done  and  aJfeo  does  away  with  the  inconvenience  of  having  a 
large  pile  of  mortar  stacked  on  the  sidewalk  or  in  the  basement. 

Among  the  earlier  buildings  using  machine-made  mdrtar  may 
be  mentioned  the  Corn  Exchange  building,  the  Manhattan  Life 
Insurance  Company's  building  and  the  Home  Life  Insurance  Com- 
pany's building  in  New  York  City.  Since  its  successful  use  in  these 
buildings  it  has  been  employed  in  many  other  large  and  important 
structures  throughout  the  country. 

The  original  and  typical  process  of  making  the  mortar  in  a 
Philadelphia  plant  is  described  as  follows : 

'Tnto  four  slaking  machines  or  revolving  pans  about  twelve 
bushels  of  lime  are  placed  and  enough  water  introduced  to  slake 
without  burning.  The  pari  is  started  and  the  lime  is  kept  in 
motion  by  a  mechanical  arrangement  of  three  feet  on  a  perpen- 
dicular shaft.  When  the  slaking  is  complete  a  plug  is  removed, 
and  the  lime  and  water  carried  by  a  trough  through  three  screens 


LATHING  AND  PLASTERING. 


78r 


into  a  well;  from  this  well  if  is  pumped  into  vats  located  in  the 
upper  stories  of  the  mixing-house.  Screening  the  lime  eliminates 
all  cores  or  underburned  limestone,  stones  and  other  foreign  matter 
so  injurious  to  mortar  and  especially  to  that  used  by  plasterers. 

''When  the  lime  and  water  are  pumped  into  the  vats  the  mixture 
much  resembles  thick  milk ;  and,  after  standing  three  weeks,  it 
assumes  the  consistency  of  soft  cheese.  Water  is  allowed  to  stand 
in  these  vats,  which  further  aids  in  the  slaking  of  any  minute  par- 
ticles'that  have  escaped  through  the  sieves  and  also  prevents  the  air 
from  reaching  the  mass.  (The  lime  used  contains  a  considerable 
amount  of  magnesia,  as  a  pure  carbonate  does  not  give  the  setting 
qualities  desirable.) 

"When  mortar  is  to  be  made  this  lime  paste  is  carried  to  the 
mixing-pans,  which  are  like  those  used  in  slaking,  except  that 
they  have  two  sets  of  feet ;  sharp,  clean  bar  sand  also  is  placed  irt 
the  pans,  and  the  machine  thoroughly  incorporates  the  lime  and. 
sand  into  a  homogeneous  mass ;  not  a  streak  of  lime  and  a  streak 
of  sand,  but  a  material  of  uniform  evenness.  As  a  result  of  this, 
care,  I  have  tested  briquettes  made  of  machine  mortar  and  have 
obtained  a  tensile  stress  as  great  as  52  pounds  to  the  square  inch ; 
in  twenty-seven  or  twenty-eight  days,  out  of  three  briquettes 
broken,  I  secured  48,  52  and  50  pounds  tensile  stress  per  square 
inch..  We  never  allow  lime  to  air-slake ;  neither  do  we  mix  the 
sand  with  the  hot  lime  and  allow  it  to  stand."* 

When  mixing  mortar  by  hand,  the  more  nearly  the  process 
approaches  the  above  order  of  procedure  the  better  will  be  the 
quality  of  the  plastering. 

656.  PROPORTION  OF  MATERIALS.  (See  also  Articles 
148  and  207.) — It  has  been  found  by  repeated  experiments  that  a 
barrel  of  Rockland  lump  lime,  thoroughly  slaked,  will  yield  on  an 
average  2.72  barrels  of  lime  paste.  Some  limes  will  yield  more 
and  others  less,  the  average  of  four  Eastern  limes  tested  being 
2.62  barrels  of  paste.  It  has  also  been  demonstrated  by  repeated 
experiments  that  the  average  sum  of  the  voids  in  sharp,  clean,, 
silicious  bank  or  pit  sand,  taken  from  different  locations  and 
thoroughly  screened,  is  .349  of  its  bulk.  It  has  been  shown  also 
that  the  best  mortar  is  obtained  by  mixing  with  the  sand  an 
amount  of  lime  paste  from  45  to  50  per  cent  greater  than  the 


*  Henry  Longcope,  in  The  Brickbiiilder. 


BUILDIXG  COXSTRUCTIOX,        (Cii.  XII) 


amount  needed  to  fill  the  voids,  which  practically  requires  a  pro- 
portion of  I  part  of  lime  paste  to  2  parts  of  sand.  This  is  the 
proportion  usually  specified  on  Government  work. 

As  it  is  difficult  to  measure  the  lime  paste,  it  is  perhaps  better 
to  specify  that  only  53^4  barrels  of  screened  sand  shall  be  used  to 
one  cask  of  lime.  Where  lime  is  sold  by  weight,  about  the  same 
proportions  are  obtained  by  specifying  2^  barrels  of  sand  to  100 
pounds  of  dry  lime. 

When  mixed  in  the  above  proportions  it  requires  about  2^/2  casks, 
or  500  pounds,  of  lime  and  14  barrels  (42  cubic  feet)  of  sand  to 
cover  ICQ  square  yards  of  lathwork  ^  of  an  inch  thick  over  the 
.laths. 

The  proportion  of  hair  to  lime  should  be,  for  first-class  work, 
jYz  bushels  of  hair  to  one  cask,  or  200  pounds,  of  lime  for  the 
scratch  coat,  and  ^  of  a  bushel  of  hair  to  one  cask  of  lime  for  the 
brown  coat.  This  is  considerably  more,  however,  than  is  found 
in  most  plasters. 

The  proportion  of  lime  given  above  is  none  too  rich  for  first- 
class  plaster,  either  for  the  brown  coat  or  the  scratch  coat ;  but  it 
is  seldom,  if  ever,  that  brown  mortar  is  made  as  rich  as  this,  and 
much  first-coat  work  is  inferior  to  it. 

In  fact,  it  is  almost  impossible  to  regulate  the  proportion  and 
uniform  mixing  of  common  lime  plaster.  Where  lime  is  sold  by 
the  cask  it  can  be  done  by  mixing  one  cask  of  lime  at  a  time  and 
measuring  the  sand ;  but  where  lime  is  sold  by  weight  it  is  necessary 
to  keep  scales  on  the  ground  for  weighing  the  lime ;  and  in  either 
case  it  is  necessary  to  have  an  inspector  to  watch  the  making  of  the 
mortar. 

.  In  practice  the  lime  is  slaked  and  as  much  sand  mixed  with  it  as 
the  mortar  mixer  thinks  best  or  the  plaster  will  stand,  and  it  is 
almost  impossible  for  the  architect  to  tell  whether  or  not  there  is 
too  much  sand.    It  seldom  happens  that  there  is  too  little  sand. 

After  considerable  experience  with  mortar,  one  can  tell  something 
about  its  quality  from  its  appearance  after  it  has  been  ''wet  up,'* 
or  by  trying  it  with  a  trowel ;  but  in  most  cases  the  architect  and 
the  owner  are  practically  at  the  mercy  of  the  contractor,  and  about 
the  best  that  can  be  done,  when  using  common  plaster,  is  to  insist 
on  the  best  materials,  mixing  in  the  hair  after  the  lime  is  cool  and 
giving  the  contract  to  an  honest  and  intelligent  plasterer. 


LATHING  AND  PLASTERING. 


783 


657.  PUTTING  ON  THE  PLASTER.— Plastering  on  lathed 
work  is  generally  done  in  three  coats.*  The  first  coat  is  called  the 
''scratch  coat,"  the  second  the  "brown  coat"  and  the  third  the 
"white  coat,"  "skim  coat"  or  "finish." 

The  Scratch  Coat. — On  brickwork  or  stonework  the  scratch  coat 
is  generally  omitted. 

The  scratch  coat  should  always  be  made  "rich,"  and  should  con- 
tain plenty  of  hair  or  fiber,  as  it  forms  the  foundation  for  the  brown 
coat  and  white  coat.  This  coat  is  generally  put  on  from  to  % 
of  an  inch  thick  over  the  laths,  and  should  be  pressed  by  the  trowel 
with  sufficient  force  to  squeeze  it  between  and  behind  the  laths,  sO' 
as  to  form  a  key  or  clinch.  It  is  this  key  which  holds  the  plaster 
to  the  laths.  When  the  first  coat  has  commenced  to  harden  (the 
time  varying  from  two  to  _  four  days)  it  should  be  scored  or 
scratched  through  almost  its  entire  thickness  with  lines  running 
diagonally  across  each  other  and  from  2  to  3  inches  apart.  This 
allows  the  second  coat  to  take  a  better  hold.  ^ 

The  first  coat  should  be  thoroughly  dry  before  the  second  coat 
is  put  on,  but  if  the  surface  is  too  dry  it  should  be  slightly  dampened 
with  a  sprinkler  or  brush  as  the  second  coat  is  applied. 

A  great  deal  of  plastering,  sometimes  called  *'green  w^ork,"  is 
done  by  applying  the  brown  coat  from  the  same  stage  used  for  the 
scratch  coat,  and  by  putting  it  on  immediately  after  the  latter. 
When  done  in  this  way  the  scratch  coat  is  generally  made  very  rich 
and  the  brown  coat  is  made  largely  of  sand,  the  brown  coat  being 
worked  into  the  scratch  coat  so  that  it  really  makes  only  one  coat. 

All  intelligent  plasterers  admit  that  better  work  results  by  letting- 
the  scratch  coat  get  dry  before  the  brown  coat  is  put  on;  but  as  it 
takes  more  labor  and  also  more  lime  to  put  on  the  plaster  in  this 
way,  they  will  not  do  it  unless  it  is  particularly  specified.  Besides 
not  making  as  good  a  wall,  the  application  of  the  brown  coat  to 
the  green  scratch  coat  also  causes  the  laths  to  swell  badly,  and  this, 
causes  cracks  in  the  plastering  when  the  laths  dry. 

The  Brown  Coat. — The  second  or  "brown"  coat  is  put  on  from 
54  to  ^  of  an  inch  thick.  With  this  coat  all  the  surfaces  should 
be  brought  to  a  true  plane,  the  angles  made  straight,  the  walls  plumb 
and  the  ceilings  level. 

*  In  the  Eastern  States  dwellings  of  moderate  cost  are  generally  plastered  with  two- 
coat  work,  the  first  or  scratch  coat  being  brought  out  nearly  to  the  grounds,  and  carefully 
straightened  to  receive  the  skim  coat. 


784 


BUILDING  CONSTRUCTION.        (Ci-i.  XII) 


On  walls  the  plastering  can  generally  be  brought  to  a  true  plane 
by  means  of  the  grounds,  if  the  latter  are  set  true  and  if  the  wall 
•surface  is  not  too  large  or  without  openings.  On  the  ceilings,  how- 
ever, there  is  usually  nothing  to  guide  the  plasterer  in  his  work,  and 
the  consequence  is  that  most  ceilings,  and  particularly  those  in 
dwellings,  have  a  rolling  surface,  which  is  particularly  apparent 
near  their  edges. 

Screeds. — The  only  way  to  make  ceilings  and  walls  true  planes, 
Avhere  the  grounds  alone  are  not  sufficient,  is  by  ''screeding,"  which 
is  done  by  applying  horizontal  strips  of  plaster  mortar,  from  6  to  8 
inches  wide  and  from  2  to  4  feet  apart,  all  around  the  room.  These 
are  made  to  project  from  the  first  coat  to  the  intended  face  of 
the  second  coat,  and  while  soft  are  made  perfectly  straight  and  out 
of  wind  with  each  other  by  testing  with  a  plumb  and  straight-edge. 
When  the  screeds  are  dry  the  second  coat  is  put  on.  This  fills  up 
the  broad  horizontal  spaces  between  them,  and  is  readily  brought  to 
a  true  surface  in  the  same  plane  as  the  screeds  by  the  use  of  long 
straight-edges. 

On  lathed  work,  if  the  studding  or  furrings  have  been  properly 
set,  screeding  should  not  be  necessary  except  on  ceilings ;  but  on 
brick,  stone,  tile  or  concrete  walls  it  is  impossible  to  get  true  surfaces 
except  by  the  use  of  grounds  or  screeds.  Screeding  was  formerly 
employed  much  more  extensively  than  at  present ;  now  it  is  seldom 
used  except  in  very  expensive  buildings.  Screeding  can  be  done 
only  in  three-coat  work.  Before  the  brown  coat  becomes  ha'rd  it 
should  be  lightly  run  over  with  the  scratcher  to  make  the  third  coat 
adhere  better.  If  part  of  the  walls  is  to  be  plastered  on  brickwork 
and  part  on  laths,  the  scratch  coat  is  put  only  on  the  laths,  and 
when  this  is  dry  the  brown  coat  is  spread  over  the  whole,  including 
the  brickwork.  Brick  walls  that  are  to  be  plastered  should  have  the 
joints  left  rough  or  open  ;  and  the  walls  should  be  cleaned  by  brush- 
ing off  all  dust  and  slightly  dampened  before  the  mortar  is  put  on. 
In  very  dry  weather  brick  walls  should  be  sprinkled  with  water 
from  a  hose  just  before  they  are  plastered. 

The  Third  or  Finishing  Coat. — The  method  of  finishing  a  wall 
varies  somewhat  in  different  parts  of  the  country  and  varies  also 
with  the  kind  of  surface  desired.  In  some  localities,  particularly 
in  small  towns  and  in  villages,  when  walls  are  to  be  papered,  no 
finishing  coat  is  applied,  the  brown  coat  or  scratch  coat  being 


LATHING  AND  PLASTERING. 


785 


smoothly  trowelled.  This,  however,  reduces  the  expense  but  a  trifle 
and  is  not  to  be  recommended,  as  the  walls  cannot  be  brought  as 
easily  to  a  true  plane  and  the  roughness  of  the  plaster  shows 
through  the  paper. 

The  Skim  Coat. — In  many  of  the  Eastern  States  the  finishing 
coat  is  called  the  ''skim  coat,"  and  is  made  of  lime  putty  and  fine 
white  sand,  generally  a  washed  beach  sand.  The  lime  is  slaked  and 
run  through  a  sieve  into  a  tight  box  and  there  allowed  to  stand  until 
it  becomes  of  the  consistency  of  putty,  when  it  is  taken  out  and 
the  sand  mixed  with  it.  The  box  containing  the  putty  should  be 
kept  covered  to  keep  out  dust  and  dirt,  and  the  putty  should  not 
be  used  until  it  is  at  least  a  week  old. 

The  skim  coat  is  put  on  with  a  trowel,  floated  down,  and  then 
gone  over  with  a  brush  and  small  trowel  until  the  surface  becomes 
hard  and  polished.  In  the  author's  opinion  this  makes  a  much 
better  finish  than  the  ordinary  ''white  coat,"  although  it  is  claimed 
that  the  latter  is  better  for  walls  that  are  to  be  painted. 

The  White  Coat. — This  term  is  generally  used  to  designate  the 
finishing  coat  when  plaster  of  Paris  is  mixed  with  the  lime  putty. 
In  most  parts  of  the  United  States  it  appears  to  be  the  custom  to 
finish  the  walls  with  a  thin  coat  of.  lime  putty,  plaster  of  Paris  and 
marble  dust.  This  makes  a  wall  that  is  whiter  than  one  finished 
\vith  a  skim  coat ;  and  if  marble  dust  is  used  and  the  work  well 
trowelled  the  surface  takes  a  good  polish.  Without  the  marble 
dust  it  is  not  so  hard  and  it  does  not  take  a  polish.  For  this  work 
the  lime  is  slaked  and  left  to  form  a  putty,  as  with  the  skim  coat. 
The  plaster  and  marble  dust  should  not  be  mixed  with  the  putty 
until  a  few  minutes  before  using,  and  then  only  as  much  should 
be  prepared  as  can  be  used  up  at  once.  If  left  standing  any 
length  of  time  it  "sets"  and  becomes  useless.  It  should  be  finished 
by  brushing  it  down  with  a  wet  brush  and  immediately  going  over 
it  with  a  trowel.  The  more  it  is  trowelled  the  harder  it  becomes. 
In  estimating  the  quantity  of  materials  required  for  the  white  coat, 
90  pounds  of  lime,  50  pounds  of  plaster  and  50  pounds  of  marble 
dust  should  be  allowed  to  100  square  yards. 

Sand  Finish. — When  a  rough  finish  is  desired  for  fresco  work, 
as  often  used  in  churches,  halls,  etc.,  the  third  coat  is  mixed  with 
lime  putty  and  sand  as  for  the  skim  coat,  except  that  coarser  sand 
and  a  greater  quantity  of  it  is  used.    Sometimes  a  small  quantity 


^S6  BUILDING  CONSTRUCTION.        (Ch.  XII) 


of  plaster  of  Paris  also  is  mixed  with  it.  Sand  finish  should  be 
applied  before  the  brown  coat  is  quite  dry,  and  should  be  floated 
with  either  clear,  soft  pine  or  cork-faced  floats.  The  roughness  of 
the  surface  desired  may  be  conveniently  designated  by  comparing  it 
with  the  different  grades  of  sandpaper. 

Sometimes  the  brown  coat  is  floated  to  give  an  imitation  of  sand 
finish,  but  it  is  impossible  to  get  an  even  and  uniform  surface 
without  using  a  separate  coat.  Sand  finish  is  often  ruled  off  and 
jointed  to  imitate  stone  ashlar.  It  may  also  be  colored  as  described 
in  Article  677,  "Colored  Sand  Finish." 

658.  HARD  WALL  PLASTERS.— By  using  only  the  best 
materials  and  mixing  them  in  the  manner  described  it  is  possible 
to  obtain  a  very  good  quality  of  wall  plaster ;  but  there  are  so  many 
chances  of  getting  an  inferior  job  when  ordinary  plaster  is 
used  that  any  material  which  can  be  used  with  greater  certainty  is 
very  mu.ch  to  be  desired.  Such  materials  appear  to  be  found  in 
the  improved  wall  plasters  placed  on  the  market  during  recent  years. 

There  are  now  several  improved  plasters  manufactured  by  dif- 
ferent companies  which,  although  diflfering  in  composition,  result, 
apparently,  in  about  the  same  kind  of  wall  covering. 

The  general  name  ''hard  wall  plaster"  has  been  given  to  these 
improved  or  patented  wall  plasters. 

There  are  two  classes  of  hard  plasters:  (i)  natural  cement 
plasters  and  (2)  chemical  or  patented  plasters. 

The  term  ''natural  cement"  is  still  used,  although  the  nature  of 
the  products  is  that  of  gypsum  rather  than  that  of  hydraulic 
cement. 

659.  NATURAL  CEMENT  PLASTERS.— In  this  class  are 
such  plasters  as  "Acme,"  "Agatite,"  "Royal,"  etc. 

The  earth  from  which  these  plasters  are  produced  is  found  in 
various  portions  of  Kansas  and  Texas.  It  is  of  a  light  ash-gray 
color  and  of  about  the  consistency  of  hard  plastic  clay,  which  it 
much  resembles  in  appearance,  though  chemically  it  is  in  the 
nature  of  an  impure  gypsum. 

When  calcined  it  assumes  a  pulverized  form.  When  mixed  with 
water  the  product  sets  and  becomes  very  hard. 

A  sample  of  "Agatite,"  after  several  weeks'  setting,  broke  under 


LATHING  AND  PLASTERING. 


7^7 


a  tensile  stress  of  370  pounds  per  square  inch.  It  is  superior  in 
strength  to  most  of  the  hydrauHc  Hmes  and  natural  cements.* 

The  various  deposits  from  which  the  plasters  here  mentioned 
are  produced  appear  to  be  of  about  the  same  grade  of  earth,  the 
plasters  differing,  if  at  all,  in  their  strength  and  working  qualities 
only.  This  is  due  principally  to  slight  differences  in  the  process  of 
manufacture. 

The  *'Acme"  cement  plaster  is  produced  by  calcining  the  natural 
earth  at  a  high  degree  of  heat  (  about  350°  Fahr.),  which  rids  the 
material  of  not  only  the  free  moisture,  but  also  of  about  75  per 
cent  of  the  combined  moisture. 

The  resulting  plaster,  when  retarded,  sets  slowly,  works  smoothly 
under  the  trowel  and  docs  not  come  to  its  normal  strength  until 
dry.    It  has  strong  adhesive  properties. 

*'Acme"  cement  plaster  was  the  first  of  this  class  to  be  put  on 
the  market.  It  has  been  extensively  used  throughout  the  country, 
and  makes  a  very  superior  wall  plaster.  Large  quantities  of  it  were 
used  in  plastering  the  World's  Fair  buildmgs,  Chicago.  *'Agatite" 
and  ''Royal,"  although  more  recently  introduced,'  have  also  been 
quite  extensively  used,  particularly  on  large  and  iniportant  buildings 
in  the  West. 

660.  CHEMICAL  OR  PATENTED  PLASTERS.— In  this 
class  are  such  wall  plasters  as  "Adamant,"  "Granite  Hard  Wall 
Plaster,"  "King's  Windsor  Cement  Dry  Mortar,"  "Paragon  Wall 
Plaster,"  "Rock  Wall  Plaster,"  "Union  Wall  Plaster,"  "Victor  Wall 
Plaster,"  etc. 

At  the  present  time  most  of  the  hard  plasters,  and  particularly 
those  in  the  East,  are  made  by  mixing  plaster  of  Paris,  hydjated 
lime,  hair,  asbestos  and  a  sufficient  "retarder"  to  keep  the  plaster  of 
Paris  from  setting  too  quickly.  This  is  for  what  is  known  as  "neat 
material." 

For  "dry  mortar"  one  part  of  the  above  compound  is  mixed  with 
two  parts  of  sand  for  lath  mortar  for  either  wooden  lath  or  metal 
lath,  and  with  three  parts  of  sand  for  brick  or  terra-cotta  walls. 

In  the  West  the  lime  is  not  used  to  any  extent,  as  it  is  difficult 
to  prepare  it  properly ;  and  it  is  cheaper  to  make  wall  plaster  in  a 
dry  state  without  the  use  of  lime. 

The  difference  in  hard  wall  plasters  really  consists  in  the  use  or 


*  Professor  Edwin  Walters,  in  Kansas  City  Journal,  January  20,  1893. 


788 


BUILDIXG  CONSTRUCTION.        (Ch.  XII) 


■omission  of  lime  and  in  the  kind  of  retarder  employed  to  make  the 
plaster  of  Paris  set  slowly.  The  greater  number  of  business  houses 
dealing  in  plasters  now  purchase  their  retarders  from  manufac- 
turers who  make  the  latter  a  specialty.  All  these  retarders  have 
practically  the  same  basis  and  are  made  from  some  form  of  glue 
stock  or  saccharine  matter. 

There  is  very  little  to-day  that  is  secret  about  the  manufacture 
of  these  plasters. 

Among  the  first  of  these  plasters  to  be  placed  on  the  market  was  ' 
the  one  known  as  "Adamant."  This  material  was  first  introduced 
in  1886  at  Syracuse,  N.  Y.,  as  a  substitute  for  lime  plaster.  It  is 
a  chemical  preparation,  and  the  manufacture  of  the  chemicals  was 
originally  covered  by  patents  and  the  chemicals  at  first  manufac- 
tured exclusively  in  that  city  by  the  original  company  and  sold  to 
licensed  companies,  who  prepared  and  sold  the  plaster. 

Since  1890  many  competitors  have  appeared  in  the  field,  each 
producing  materials  whose  claims  have  generally  met  with  the 
approval  of  architects  and  builders. 

"King's  Windsor  Cement"  is  made  by  mixing  certain  ingredients 
with  plaster  of  Paris  or  calcined  plaster,  calcined  from  a  superior 
quality  of  Nova  Scotia  gypsum. 

"King's  Windsor  Cement  Dry  Mortar"  is  the  above  composition 
mixed  with  the  correct  portion  of  washed  and  kiln-dried  bank  sand. 

In  the  manufacture  of  these  plastering  products  all  the  ingredi- 
ents are  automatically  weighed  and  thoroughly  mixed  by  special 
machinery,  thus  insuring  the  requisite  strength  and  uniformity  in 
both  quaUty  and  working.  It  is  claimed  that  no  acids  are  used  in 
thei^manufacture  and  that  therefore  they  will  not  rust  nor  corrode 
structural  steel,  metal  lath,  etc. 

Windsor  Cement  is  manufactured  in  the  Borough  of  Richmond, 
New  York,  N.  Y.,  and  has  been  used  extensively  in  many  public 
and  private  buildings  in  that  city  and  to  a  large  extent  throughout 
the  Eastern  and  Middle  States.  • 

"Rock  Wall  Plaster"  is  manufactured  in  upper  New  York  City. 
The  different  ingredients  are  selected,  weighed  and  thoroughly 
weighed  by  machinery.  The  product  is  put  up  in  bags  in  a  dry  state 
and  is  ready  for  use  when  sent  to  a  building,  requiring  only  the 
addition  of  water  to  moisten  it  before  applying  it  to  a  wall.  It  is 
made  from  slaked  lime,  sharp  and  cleaned  kiln-dried  sand,  with  a 


LATHING  AND  PLASTERING. 


789 


proper  proportion  of  plaster  of  Paris,  asbestos  and  whipped  cattle 
hair. 

Rock  Plaster  differs  from  other  hard  wall  plasters  in  being  made 
principally  of  lime  which  goes  through  a  process  of  "aging."  This, 
it  is  claimed,  increases  the  strength  of  the  plaster  as  time  goes  on. 
It  is  not  as  hard  as  other  hard  wall  plasters  are  soon  after  they 
are  put  on ;  but  within  a  month  it  becomes  very  hard  and  continues 
to  improve  with  age,  when  properly  handled  and  applied. 

''Paragon  Wall  Plaster"  is  made  in  Syracuse,  N.  Y.,  and  has 
become  widely  and  favorably  known  to  the  building  trades.  It  is 
made  by  established  formulas,  mixed  by  power  and  is  uniform,  in 
its  composition.  It  is  free  from  acids,  has  little  or  no  tendency 
to  disintegrate  and  grows  harder  with  age.  This  same  company 
has  recently  introduced  also  a  wood  fiber  wall  plaster  called  "The 
Twentieth  Century  Wall  Plaster,"  and  containing  no  sand. 

There  are  other  wood  fiber  plasters. 

The  "Victor  Wall  Plaster"  (and  "Adamant"  also)  is  made  in 
Chester,  Pa.,  and  the  "Union  Wall  Plaster"  is  made  in  Wilming- 
ton, Del. 

A  preparation  called  "Granite  Hard  Wall  Plaster"  is  made  in 
]\Iinneapolis,  Minn.,  and  many  similar  preparations  are  made  by 
local  companies  in  several  localities. 

As  far  as  the  author  has  been  able  to  ascertain  all  of  these 
materials  give  good  results  when  properly  handled. 

661.  HOW  SOLD. — All  of  the  plasters  above  described  are 
packed  in  sacks,  or  bags,  holding  80,  100,  125  or  140  pounds  each. 

"Acme,"  "Agatite"  and  "Royal"  wall  plasters  are  sold  in  the 
form  of  cement  only,  and  the  sand  is  mixed  with  the  cement  as  the 
latter  is  used  by  the  plasterer. 

Two  kinds  of  cement  are  sold,  one  mixed  with  fiber,  and  known 
as  "fibered  cement,"  and  the  other  without  fiber.  The  fibered  cement 
should  be  used  for  the  first  coat  on  lathed  work,  whether  of  wood 
or  metal.  On  brickwork  or  fire-proof  tiling,  fiber  is  not  required, 
.and  the  unfibered  cement  should  be  used. 

The  unfibered  cement  is  used  also  for  the  second  or  brown  coat 
•and  wherever  the  plaster  is  to  be  trowelled  down  to  a  smooth,  hard 
:surface.  Where  the  plaster  is  to  be  finished  with  a  white  surface 
it  is  necessary  to  use  lime  and  plaster  of  Paris  (as  on  lime  plaster) 
over  these  cements,  as  they  are  of  a  gray  color. 


790  BUILDING  CONSTRUCTION.        (Ch.  XII> 

"Windsor  Cement"  is  sold  in  two  forms:  (i)  ''Windsor  Cement, 
Neat,"  which  is  to  be  mixed  with  sand  by  the  local  contractor  at 
the  work  in  the  proportion  of  one  part  of  cement  to  two  parts  of 
sand  for  application  on  wooden  lath  or  metal  lath  and  of  one  part 
of  cement  to  three  parts  of  sand  for  application  on  brickwork,  terra- 
cotta or  concrete ;  the  cement  and  sand  are  thoroughly  mixed 
together  before  the  water  is  added;  (2)  ''Windsor  Cement  Dry 
Mortar,"  which  is  ready  for  immediate  use  by  the  addition  of  water 
only. 

"Rock  Wall  Plaster,"  "Union  Wall  Plaster,"  "Victor  Wall  Plas- 
ter," "Adamant"  and  some  others  are  sold  both  "neat"  and  mixed 
with  sand,  all  ready  for  applying  by  simply  mixing  with  clean  water. 
Two  grades  of  these  plasters  also  are  made,  one  for  applying  on 
wooden  or  metal  lath  work  and  the  other  for  applying  on  brick, 
terra-cotta,  concrete,  etc.,  the  only  difiference  between  the  two  being 
that  the  latter  contains  more  sand  than  the  former.  All  of  these 
plasters  are  made  for  furnishing  several  dififerent  kinds  of  finishing 
coats  and  surfaces. 

662.  APPLICATION.— The  method  of  applying  these  plaster^ 
does  not  dififer  materially  from  that  already  described  for  lime 
mortar,  except  that  the  second  coat,  corresponding  to  the  brown 
coat,  is  put  on  directly  after  the  first  coat  and  finished  with  the 
darby  instead  of  with  the  float.  The  scratch  coat  must  be  left 
rough  and  either  scored  or  broomed,  so  that  there  will  be  a  sufficient 
bond  between  the  scratch  coat  and  the  brown  coats.  Being  of  the 
nature  of  plaster  of  Paris,  these  mortars  set  instead  of  drying,  and 
but  little  water  should  be  used  in  working  them.  Only  as  much 
material  should  be  mixed  as  can  be  applied  in  one  and  a  half  hours, 
and  material  that  has  commenced  to  set  should  never  be  remixed. 

Clean  water  only  should  be  used,  and  the  tools  and  mortar  box 
should  be  kept  perfectly  clean  and  the  box  cleaned  out  after  each 
mixing. 

When  using  the  hard  plasters  on  wooden  laths  the  laths  should 
be  thoroughly  dampened,  or  expanded,  before  the  plaster  is  spread, 
so  that  they  will  not  swell  after  the  plaster  has  commenced  to  set. 
Brickwork,  stonework,  concrete-work  and  tilework  also  should 
be  zvell  sprinkled  before  applying  these  mortars. 

Most  of  the  manufacturers  of  hard  plasters  recommend  that  when 
their  plasters  are  used  the  laths  be  spaced  only  J4  of       hich  apart, 


LATH IX G  AXD  PLASTERING. 


791 


and  that  ^-inch  grounds  be  used,  claiming  that  a  smaller  quan- 
tity of  their  material  is  required  than  is  the  case  with  ordinary  lime 
mortar. 

A  gentleman  who  has  had  much  experience  with  cement  plasters 
says,  however,  that  ''More  failures  in  hard  wall  plastering  result 
from  too  thin  coats,  too  weak  keys  and  too  weak  material  (when 
sold  unmixed  with  sand)  than  from  any  other  cause. 

*'To  do  a  good  job  of  hard  plastering  it  is  necessary  to  use  a' 
sufficient  amount  of  cement  for  tensile  strength,  to  secure  a  good 
wide  key  and  to  put  on  a  good  thick  coat  of  the  plaster.  Where 
it  is  spread  very  thin  it  is  sure  to  crack  and  to  result  in  an  unsat- 
isfactory wall  covering.'' 

For  lathwork  a  better  wall  will  be  obtained,  although  at  a 
slightly  increased  expense,  by  putting  on  J^-inch  grounds  and 
spacing  the  laths  for  a  ^-inch  key. 

All  of  these  plasters  can  be  finished  with  a  third  coat,  as  described 
in  Article  657.  This  coat  should  in  no  case  be  applied  until  the 
t)ase  is  thoroughly  dry. 

Sand  finish  should  be  made  as  a  separate  finish  at  the  mills. 

Full  directions  for  applying  the  various  grades  of  these  plasters 
;are  furnished  by  the  manufacturers,  and  architects  should  see  that 
these  instructions  are  carefully  and  faithfully  followed.  When  they 
are  improperly  applied  these  plasters  are  inferior  to  ordinary  lime 
mortar. 

663.  ADVANTAGES  IN  USING  HARD  WALL  PLAS- 
TERS.— The  principal  advantages  gained  by  the  use  of  these 
plasters  are:  uniformity  in  strength  and  quality;  greater  hardness 
and  tenacity;  freedom  from  pitting;  less  weight  and  moisture  in 
the  building;  saving  in  time  required  for  making  and  drying  the 
plaster;  minimum  danger  from  frost;  and  greater  resistance  to  fire 
and  water. 

Frost  does  not  harm  these  plasters  after  they  have  commenced 
to  set  or  after  chemical  action  has  taken  place.  When  used  in 
freezing  weather  they  must  not  be  allowed  to  freeze  during  the  first 
thirty-six  hours  after  applying;  after  that  time  frost  does  no  harm. 

Those  plasters  which  are  already  mixed  with  sand  and  fiber  have 
the  additional  advantage  also  of  thorough  and  uniform  mixing  of 
the  materials  and  absolute  correctness  of  proportions.  This  latter 
.advantage   is  perhaps  appreciated  most  by  the  architect,  as  it 


792 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


prevents  all  chance  of  using  a  poor  quality  of  sand,  or  too  much 
of  it ;  and  it  also  saves  him  a  great  deal  of  labor  in  the 
superintendence. 

The  benefit  to  the  owner  in  using  these  plasters  consists  in  secur- 
ing much  more  substantial  walls  than  is  possible  with  the  ordinary 
hand-made  mortar,  less  risk  from  fire  and  less  expense  on  account 
of  repairs. 

The  slight  additional  expense  of  using  them  is  hardly  to  be  con- 
sidered when  it  is  compared  with  the  benefits  obtained ;  and  it  is 
probable  that  these  plasters  will  be  still  more  generally  adopted, 
as  they  are  already  extensively  used  in  the  largest  and  most  costly 
buildings. 

For  mercantile  buildings  the  saving  in  the  time  required  for 
drying  the  plastering  more  than  pays  for  the  additional  expense. 

On  account  of  their  greater  density  these  mortars  will  not  harbor 
vermin  nor  absorb  noxious  gases  and  disease  germs,  and  they  are 
therefore  especially  desirable  for  hospitals,  schools,  etc.  Heat,  air 
and  moisture  will  not  pass  through  them  as  through  lime  plaster. 

A  wall  covering  of  hard  plaster  on  wooden  or  metal  lath  is  also 
much  more  resonant  than  one  of  lime  mortar,  vmless  equivalent 
thicknesses  of  mortar  are  applied;  and  for  this  reason,  and  also  on 
account  of  their  greater  strength,  these  mortars  are  valuable  for 
plastering  churches,  opera-houses  and  public  halls. 

664.  INTERIOR  STUCCOVv^ORK.— This  term,  as  commonly 
used  in  this  country,  refers  to  ornamental  interior  plasterwork, 
such  as  cornices,  moldings,  centerpieces,  etc.  For  such  work  a 
mixture  of  lime  paste  and  plaster  of  Paris  is  used,  except  for  cast 
work,  which  is  made  entirely  of  plaster  of  Paris. 

Plaster  of  Paris  is  produced  by  the  gentle  calcination  of  gypsum 
to  a  point  short  of  the  expulsion  of  the  whole  of  the  moisture. 
Paste  made  from  it  sets  in  a  few  minutes,  and  attains  its  full 
strength  in  an  hour  or  two.  At  the  time  of  setting  it  expands  in 
volume,  and  this  property  makes  it  especially  valuable  for  taking 
casts,  making  cast  ornaments  for  walls  and  ceilings,  and  patching 
and  repairing  ordinary  plasterwork. 

When  added  to  lime  mortar,  plaster  of  Paris  causes  the  mortar 
to  set  or  harden  very  quickly,  and  for  this  reason  it  is  often  mixed 
with  mortar  to  be  used  for  patching  or  repairing.  Work  of  this 
kind  is  called  ''gauged  work." 


LATHING  AND  PLASTERING. 


.  793 


Plaster  of  Paris  is  very  apt  to  crack  when  used  clear  or  ''neat," 
and  when  its  thickness  is  considerable.  Cast  ornaments  made  of  it 
are  therefore  usually  made  hollow  or  with  a  thin  shell.  For  work 
that  is  to  be  run,  or  worked  by  hand,  it  cannot  be  used  neat,  as  it 
sets  too  quickly.  It  is  for  this  reason  that  lime  putty  is  mixed 
with  it. 

For  moldings,  cornices,  etc.,  a  mixture  of  about  2  parts  of  plaster 
of  Paris  to  i  part  of  lime  paste  is  used. 

Plain  moldings,  whether  in  a  cornice  or  centerpiece,  or  on  a  wall 
or  ceiling,  are  usually  run  in  place  by  hand.  The  process  con- 
sists in  spreading  on  the  surface  of  the  wall  or  ceiling  a  sufficient 
body  of  plaster  and  in  forming  the  mold  by  running  along  it  a  sheet- 
iron  template,  cut  to  the  reverse  profile  of  the  mold.  This  template 
is  stiffened  by  wooden  cleats  and  provided  with  struts  to  keep  its. 
plane  always  perpendicular  to  the  plane  of  the  surface  on  which  the 
mold  is  run.  The  stuccowork  is  always  run  before  the  finishing 
coat  of  plaster  is  applied,  as  it  is  necessary,  to  fasten  light  pine 
straight-edges  on  the  walls  to  form  guides  for  the  templates.  In 
running  the  molding  two  men  are  generally  required,  one  to  put 
on  the  plaster  as  it  is  needed  and  the  other  to  work  the  template, 
which  generally  has  to  be  worked  back  and  forth  several  times 
before  the  molding  is  finished. 

The  whole  molding  or  cornice  between  any  two  breaks  or  pro- 
jections should  be  completed  at  once,  so  that  the  entire  length  may 
be  uniform  in  shape  and  shade. 

The  miters  at  the  angles,  both  internal  and  external,  have  to  be 
finished  by  hand  by  using  a  small  trowel  and  a  straight-edge. 

If  the  cornice  or  moldinof  contains  much  ornamental  work  it  is 
cheaper  to  cast  it  in  sections,  each  about  2  feet  in  length,  and  attach 
it  to  the  wall  by  means  of  liquid  plaster  of  Paris.  Great  care  is 
required  in  cast  work  to  join  the  sections  so  that  the  fines  of  the 
moldings  will  be  perfectly  straight.  • 

If  there  are  only  one  or  two  enriched  members  the  rest  of  the 
molding  or  cornice  may  be  run  in  the  usual  way,  leaving  sinkings 
to  receive  the  enriched  members,  which  are  then  cast  and  stuck  in 
place,  as  at  A,  Fig.  623. 

In  designing  cornices  or  belt-moldings  care  should  be  taken  to 
have  not  more  than  a  3-inch  thickness  of  plaster  at  any  point.  If 
the  moldings  require  a  thickness  of  material  greater  than  this  the 


794  , 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


wall  or  angle  should  be  blocked  and  lathed,  as  in  Fig.  623,  so  as 
to  reduce  to  a  minimum  the  amount  of  plaster  required.  When  the 
projection  is  only  about  3^  or  4  inches  the  back  may  be  formed 
of  brown  mortar  (Fig.  624),  containing  a  little  plaster  of  Paris, 
and  held  in  place  by  projecting  spikes  or  large  nails  driven  into 
the  wall  or  ceiling  before  the  mortar  is  put  on. 

Center  ornaments  consisting  of  plain  circular  moldings  only 
are  run  in  the  same  way  as  other  molded  work,  except  that 
the  template  is  attached  to  a  piece  of  wood  which  is  pivoted  at  the 
center  of  the  ornament.  Enriched  centers  are  cast  in  a  mold  and 
stuck  to  the  ceiling  after  the  finishing  coat  is  on. 


All  kinds  of  ornaments,  such  as  panelled  ceilings,  bas-reliefs, 
imitations  of  foliage,  etc.,  may  readily  be  executed  in  plaster  of 
Paris ;  and  when  the  ornaments  are  placed  in  such  positions  that 
they  cannot  be  injured  by  objects  in  the  room,  it  answers  as  well 
as  harder  and  more  expensive  materials. 

Since  hardwood  finish  has  become  so  common,  however,  it  has 
largely  supplanted  the  plaster  cornices  that  were  so  much  used  up 
to  about  the  middle  of  the  last  century. 

Stuccowork  is  generally  included  in  the  plasterer's  specifications. 
As  it  is  much  more  expensive  than  ordinary  plastering,  the  quantity 


LATHING  AND  PLASTERING. 


795 


i 


and  character  of  it  should  be  clearly  indicated  on  the  drawings  and 
in  the  specifications  and  by  full-size  details/ 

For  enriched  work  the 
architect    should    require  ^^^^^^^^^^^^J'^^yi 
that  the  models  be  ap- 
proved by  him  before  the 
casts  are  made. 

665.  KEENE'S  CE- 
MENT.— When  it  is  desired  to  finish  plastered  walls, 
ceilings,  columns,  etc.,  with  a  very  hard  and  highly 
polished  surface  Keene's  cement  is  generally  used 
for  the  finishing  coat.  This  cement  is  a  plaster  pro- 
duced by  recalcining  plaster  of  Paris  after  soaking 
it  in  a  saturated  solution  of  alum.  This  material  is 
very  hard  and  capable  of  taking  a  high  polish,  and 
walls  finished  with  it  may  be  sponged  with  soft  water 
without  injury. 

It  is  especially  valuable  for  finishing  plastered  col- 
umns, the  lower  portions  of  walls  and  wherever  the 
plaster  is  liable  to  injury  from  contact  with  furniture, 
etc.  It  is  also  used  in  the  manufacture  of  artificial 
marble. 

The  manufacturers  of  King's  Superfine  Windsor 
Cement  and  of  some  other  materials  of  a  similar  fig-  ^ 
nature  claim  that  for  finishing  walls  it  is  equal  to  the 
imported  Keene's  cement.     It  is  considerably  less 
expensive. 

On  account  of  their  solubility  none  of  these  materials  should  be 
used  in  situations  greatly  exposed  to  the  weather. 

666.  SCAGLIOLA  is  a  coating  applied  to  walls,  columns,  etc., 
to  imitate  marble.  The  name  is  derived  from  ''Scaglia,"  the  rock 
from  which  the  ancient  Italians  made  their  plaster.  The  base  or 
groundwork  is  generally  of  mortar  made  of  good  plaster  of  Paris 
and  clean  sharp  torpedo  sand  containing  a  large  proportion  of  hair. 
After  this  has  set  and  is  quite  dry  it  is  covered  with  a  floated  coat, 
consisting  of  plaster  of  Paris  or  Keene's  cement,  mixed  with  various 
coloring  matters  in  a  solution  of  glue,  to  give  greater  solidity  and 
to  prevent  the  plaster  of  Paris  from  setting  too  quickly.  When  the 
surface  is  thoroughly  hard  it  is  rubbed   with   pumice-stone  and 


Interior 
Stucco  Cornice. 
Small  Projec- 
tion. 


796 


BUILDING  CONSTRUCTION. 


(Ch.  XII) 


Scotch-hone  and  then  rubbed  until  it  looks  like  polished  marble. 
Columns  are  made  in  this  way  which  are  with  difficulty  distinguished 
by  the  eye  from  marble. 

Imitation  marble,  when  in  flat  slabs,  is  commonly  made  on  sheets, 
of  plate-glass.  Threads  of  floss  silk,  which  have  been  dipped  into 
the  veining  colors,  previously  mixed  to  a  semi-fluid  state  with  plaster 
of  Paris  or  Keene's  cement,  are  placed  upon  a  sheet  of  plate-glass 
so  as  to  resemble  the  veins  in  the  marble  to  be  imitated.  Upon  this 
the  body  color  of  the  marble  is  placed  by  hand.  The  silk  is  thert 
withdrawn  and  dry  plaster  of  Paris  is  sprinkled  over  to  take  up  the 
excess  of  moisture  and  to  give  the  whole  the  proper  consistency.  A 
backing  of  Keene's  cement  or  plaster  of  Paris  of  any  desired  thick- 
ness is  then  applied.  Canvas  is  sometimes  placed  in  the  backing 
to  give  it  greater  strength.  After  removal  from  the  glass  the  slab 
is  polished  and  set  in  place  in  the  same  manner  as  the  genuine 
material.  This  work  naturally  requires  much  skill  as  well  as  prac- 
tice and  experience  on  the  part  of  the  workmen. 

A  great  deal  of  scagliola  has  been  used  in  Europe,  and  in  recent 
years  several  companies  have  been  formed  in  America  for  making 
artificial  marble.  For  interior  work  scagliola  should  be  as  durable 
as  marble,  and  there  are  columns  of  it  in  Europe  several  hundred 
years  old.  It  should  not  be  used  on  the  exterior  of  buildings,  as  it 
will  not  bear  exposure  to  the  weather. 

In  the  newer  improved  processes  of  manufacture  great  advances 
have  been  made.  In  fact  the  newer  marbles  cannot  be  made  by 
the  old  scagliola  methods.  Any  marble  can  now  be  imitated  by  the 
newer  processes,  and  in  all  imitated  marbles  the  artist  is  the  main 
thing,  the  process  being  reallv  of  secondary  consideration." 

In  some  of  the  best  of  the  recent  works  Keene's  cement  is  used 
for  body  and  face  and  also  for  setting,  no  Portland  cement,  plaster 
of  Paris  or  hard  wall  plasters  being  used. 

Imitation  marbles  are  made  into  architectural  designs,  slabs  of 
any  size,  moldings  of  any  form,  columns  of  any  dimensions, 
pilasters,  pedestals,  wainscotings,  altars,  mantels,  etc. 

667.  FIBROUS  PLASTER.— This  consists  of  a  thin  coating 
of  plaster  of  Paris  on  a  coarse  canvas  backing  stretched  on  a  light 
framework  and  formed  into  slabs.  For  casts,  about  34  of  ii^ch 
of  plaster  is  put  in  the  mold  and  the  canvas  then  put  on  the 
back  and  slightly  pressed  into  the  plaster.    Fibrous  plaster  is  very 


LATHING  AND  PLASTERING. 


797 


light  and  strong,  and  can  be  easily  handled  without  breaking.  It 
is  extensively  used  in  England  for  ornamental  work,  and  in  Brazil 
it  is  said  to  be  used  extensively  for  exterior  work. 

668.  CARTON-PIERRE. — This  is  a  material  used  for  making 
raised  ornaments  for  wall  and  ceiling  decoration.  It  is  composed 
of  whiting  mixed  with  glue  and  the  pulp  of  paper,  rags  and  some- 
times hemp,  which  is  forced  into  plaster  or  gelatine  molds,  backed 
with  paper,  and  then  removed  to  a  drying-room  to  harden.  It  is 
much  stronger  and  lighter  than  common  plaster  of  Paris  when  made 
into  ornaments,  and  is  not  so  apt  to  chip  or  break  when  struck. 

Ornaments  of  carton-pierre,  under  different  names,  are  now 
extensively  used  in  this  country  for  decorating  rooms,  making; 
mantels,  etc.,  and  also  to  some  extent  on  the  exterior  of  buildings. 
If  kept  painted  there  appears  to  be  no  reason  why  it  should  not 
last  for  many  years,  except  when  placed  in  very  exposed  positions. 

669.  EXTERIOR  PLASTERING.— This  "^is  generally  either 
*'rough-cast"  or  stuccowork.  The  first  is  a  kind  of  coarse  plaster- 
ing generally  applied  on  laths ;  the  second  is  plastering  on  brick- 
work executed  so  as  to  resemble  stone  ashlar. 

Rough-cast  has  been  extensively  used  in  Canada  and  to  some 
extent  in  the  Northern  States.  It  is  said  to  be  much  warmer  than 
siding  or  shingles,  less  expensive  and  quite  as  durable.  It  is  also 
more  fire-resisting. 

''There  are  frame  cottages  near  the  city  of  Toronto,  Canada,  and 
along  the  northern  shores  of  Lake  Ontario  which  were  plastered 
and  rough-casted  on  the  outside  over  forty  years  ago ;  and  the 
mortar  to-day  is  as  good  and  as  sound  as.  when  first  put  on,  and 
looks  as  though  it  is  good  for  many  years  to  come  provided  the 
timbers  of  the  building  it,  preserves  remain  sound. 

'Tt  is  quite  a  common  occurrence  in  the  winter  in  Manitoba  and 
the  Northwest  Canadian  Territories  to  find  the  mercury  frozen  ;  yet 
this  intense  cold  does  not  seem  to  afifect  the  rough-casting  in  the 
least,  although  in  many  cases  it  chips  bricks,  contracts  and  expands 
limber  and  renders  stone  as  brittle  as  glass."* 

Frame  buildings  to  be  rough-casted  should  be  covered  with 
sheathing  and  one  thickness  of  tarred  paper.  The  partitions  should 
be  not  only  put  in  but  also  lathed  before  the  outside  is  plastered^ 
as  it  is  important  to  have  the  building  stiff  and  well  braced. 


*  "Rough-casting  in  Canada,"  by  Fred.  T.  Hodgson,  Architecture  and  Building^ 
March  24,  1894. 


798 


BUILDING  CONSTRUCTION. 


(Ch.  XII) 


The  most  approved  procedure  for  rough-cast  work,  as  practiced  - 
in  the  lake  district  of  Ontario,  is  said  to  be  as  follows : 

The  laths  should  be  No.  i  pine  laths,  placed  diagonally  over  the 
sheathing  or  tarred  paper,  keeping  i}4-inch  spaces  between  the 
laths.  Each  lath  should  be  nailed  with  five  nails  and  joints  should 
be  broken  every  i8  inches.  A  second  covering  of  laths  should 
be  laid  diagonally  in  the  opposite  direction,  keeping  the  same 
space  between  the  laths  and  breaking  joint  as  before.  Careful  and 
solid  nailing  is  required  for  this  layer  of  lathing,  as  the  permanency 
of  the  work  depends  to  some  extent  on  this  portion  of  it  being 
honestly  done.  The  first  coat  should  consist  of  rich  lime  mortar, 
with  a  large  proportion  of  cow's  hair,  and  should  be  mixed  at  least 
four  days  before  using.  The  operator  should  see  to  it  that  the 
mortar  be  well  pressed  into  the  keys  or  interstices  of  the  lathing  to 
make  it  hold  thoroughly.  The  face  of  the  work  should  be  well 
scratched  to  form  a  key  for  the  second  coat,  which  must  not  be 
put  on  before  the  first  or  scratch  coat  is  dry.  The  mortar  for  the 
second  coat  is  made  in  the  same  way  as  for  the  first  coat,  and  is 
applied  in  a  similar  manner,  except  that  the  scratch  coat  is  well  - 
dampened  before  the  second  coat  is  put  on,  in  order  to  keep  the 
second  coat  moist  and  soft  until  the  dash  or  rough-cast  is  thrown  on. 

The  "dash,"  as  it  is  called,  is  composed  of  fine  gravel,  washed 
clean,  freed  from  all  earthy  particles  and  mixed  with  pure  lime 
and  water  until  the  whole  is  of  a  semi-fluid  consistency.  This  is 
mixed  in  a  shallow  tub  or  pail  and  is  thrown  upon  the  plastered 
wall  with  a  wooden  float  about  5  or  6  inches  square.  While  the 
plasterer  throws  on  the  rough-cast  with  the  float  held  in  his  right 
hand,  he  holds  in  his  left  a  common  whitewash  brush,  which  he 
dips  into  the  dash  and  with  which  he  brushes  over  the  mortar  and 
rough-cast,  giving  them,  when  finished,  a  regular  uniform  color 
and  appearance. 

For  100  yards  of  rough-casting,  done  as  above  described,  the  fol- 
lowing quantities  are  required:  1,800  laths,  12  bushels  of  lime, 
barrels  of  best  cow  hair,  yards  of  sand,  ^  of  a  yard  of  prepared 
gravel  and  16  pounds  of  cut  lath  nails  i>4  inches  long.  A  quarter- 
barrel  of  lime  putty  should  be  mixed  with  every  barrel  of  prepared 
gravel  for  the  dash  which  may  be  colored  as  desired  by  using  the 
proper  pigments. 

To  color  100  yards  in  any  of  these  tints  named  the  follow- 


LATHING  AND  PLASTERING. 


799 


ing  quantities  of  ingredients  should  be  used :  For  a  blue-black,  5 
pounds  of  lampblack ;  for  buff,  5  pounds  of  green  copperas,  to 
which  should  be  added  i  pound  of  fresh  cow  manure,  strained  and 
mixed  with  the  dash.  A  fine  terra-cotta  color  is  made  by  using  15 
pounds  of  metallic  oxide,  mixed  with  5  pounds  of  green  copperas 
and  4  pounds  of  lampblack.  Many  tints  of  these  colors  may  be 
obtained  by  varying  the  quantities  given.  The  colors  obtained  by 
these  methods  are  permanent ;  they  do  not  fade  nor  change  with 
time  or  atmospheric  variations.  Earthy  colors,  like  Venetian  reel 
and  umber,  soon  fade  and  have  a  sickly  appearance. 

Expanded-metal,  perforated,  or  stiffened  wire  lathing  are  un- 
doubtedly better  than  wooden  laths  for  external  plastering,  as  they 
hold  the  plaster  better  and  also  afford  greater  protection  from  fire. 

The  following  description  of  external  plastering,  as  used  by  an 
architect  of  considerable  experience  with  this  sort  of  work,  was 
published  in  The  Brickbuilder  for  August,  1895,  and  represents 
probably  the  best  current  practice  in  this  country : 

"I  always  use  three-coat  work,  the  first  coat  being  well-haired 
mortar  with  one-third  Portland  cement  added  when  ready  for  use. 
This  coat  is  well  scratched.  The  second  coat  is  the  same,  with  the 
omission  of  the  hair  ;  and  the  third  coat  has  the  same  proportions, 
but  has  coarse  sand  or  gravel,  either  floated  or  put  on  as  slap-dash„ 
according  to  the  kind  of  finish  I  wish  to  obtain. 

"I  occasionally  use  a  very  small  quantity  of  ochre  in  this  last 
coat,  but  it  has  to  be  mixed  very  thoroughly  and  carefully  in  order 
to  produce  an  even  color. 

'  "This  plasterwork  I  have  applied  on  wood  lath  over  studs  and 
without  rough  boarding  behind  it.  I  have  applied  it  also  over 
rough  boarding,  furring  and  wood  lath,  which  is  a  better  construc- 
ion.  When  applied  over  rough  boarding,  furring  and  wire  lath 
it  makes  the  best  construction  of  all. 

''A  small  church  plastered  in  this  way  on  wood  lath  in  1881 
is  in  perfect  condition  to-day,  arid  various  houses  built  during 
the  last  ten  years  have  proved  perfectly  satisfactory.  I  have  not 
as  yet,  however,  found  any  method  of  building  true  half-timbered 
work  and  of  making  it  thoroughly  tight  without  constructing  a 
wall  that  is  practically  as  expensive  as  a  brick  wall." 

670.  EXTERIOR  STUCCOWORK.— Exterior  plastering  of 
buildings  was  at  one  time  greatly  in  vogue  in  European  countries,. 


oOO 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


and  there  are  many  examples  in  those  portions  of  the  United  States 
which  have  the  oldest  buildings.  Lime  and  sand  were  formerly 
used  for  the  purpose,  but  this  mixture  is  not  very  durable.  If  it  is 
desired  to  plaster  a  brick  building  to  imitate  stone  ashlar,  Portland 
cement  is  the  only  material  that  should  be  used.  It  should  be  mixed 
with  clean  sharp  sand  which  is  not  too  fine,  in  the  proportion  of 
3  parts  sand  to  i  part  of  cement.  The  walls  to  be  covered  should 
themselves  be  dry,  but  the  surface  should  be  well  wet  down  with 
water  from  a  hose  to  prevent  it  from  at  once  absorbing  all  the 
water  in  the  cement.  The  surface  should  be  sufficiently  rough,  also, 
tto  form  a  good  key  for  the  cement.  Screeds  may  be  formed  on 
ithe  surface,  and  the  cement  mortar  applied  in  one  coat  of  uniform 
thickness  throughout.  When  cement  mortar  is  put  on  in  two  or 
three  coats,  whether  in  exterior  or  interior  work,  a  coat  already, 
.applied  should  on  no.  account  he  allowed  to  dry  before  a  succeeding 
ccoat  is  added.  When  this  drying  takes  place  the  layers  are  quite 
.sure  to  separate. 

The  manufacturers  of  ''Acme"  cement  plaster  claim  that  where 
brick  buildings  are  to  be  plastered  on  the  outside  with  cement  their 
plaster  is  superior  to  Portland  cement  mortar  for  the  first  coat,  as 
it  adheres  more  firmly  to  the  bricks,  and  holds  together  the  Port- 
land cement  and  the  base  upon  which  it  is  spread. 
'  Before  it  becomes  hard  the  cement  may  be  marked  with  lines 
to  represent  stone  ashlar.  If  it  is  desired  to  color  the  cement, 
mineral  pigments,  such  as  Venetian  red  or  the  ochres,  must  be  used. 
The  natural  color  of  the  cement  may  be  lightened  by  the  addition 
>of  a  very  little  lime. 

671.  STAFF.* — Stafif,  a  material  used  for  the  exterior  covering 
of  all  the  buildings  of  the  World's  Columbian  Exposition  at  Chicago 
in  1893,  and  for  most  of  the  buildings  of  the  expositions,  held  since 
then,  may  be  considered  as  a  comparatively  new  material  in  this 
country,  although  it  has  been  in  extensive  use  in  Europe  for  many 
years.  A  large  part  of  all  exterior  decoration  of  buildings,  both 
public  and  private,  in  the  provincial  cities  of  Germany,  whether 
ornament,  columns  or  statuary,  is  made  of  stafif ;  and  in  some  in- 
stances a  period  of  fifty  years  of  existence  testifies  to  its  enduring 
.qualities.    Stafif  was  first  used  extensively  in  the  construction  of 


*  The  following  description  of  this  material  is  taken  from  an  article  by  Mr.  E.  Phillip- 
son,  published  in  the  Engineering  Record  of  June  4,  1892.  Mr.  Phillipson  had  charge  of 
(this  portion  of  the  work  on  the  Chicago  World's  Fair  buildings. 


LATHING  AND  PLASTERING. 


8oi 


buildings  at  the  Paris  Exposition  of  1878,  and  it  was  also  adopted 
in  work  on  the  much  larger  and  grander  buildings  of  the  exposi- 
tion of  1889.  The  methods  of  application  at  these  expositions  were, 
however,  widely  different  from  and  much  more  expensive  than  those 
employed  at  the  Columbian  Exposition  in  this  country. 

The  staff  for  the  World's  Fair  buildings  was  made  on  the 
grounds  at  Jackson  Park,  Chicago,  in  the  following  manner: 

The  ingredients  were  simply  plaster  of  Paris,  or  Michigan 
plaster,  water  and  hemp  fiber.  Hemp  was  used  to  bind  together 
and  add  strength  to  the  cast,  and  the  New  Zealand  fiber  was  pre- 
ferred, as  both  the  American  and  Russian  fibers  were  found  to  be 
too  stiff.  The  first  step  in  making  staff  ornaments  is  the  creation 
of  a  clay  model.  The  model  is  heavily  coated  with  shellac,  and  a 
layer  of  clay  separated  from  the  model  by  paper  is  put  on  its  face 
and  sides.  This  layer  of  clay  is  oiled  or  greased  and  a  heavy  coat- 
ing of  plaster  and  hemp  is  put  over  it.  The  thickness  of  this  coat- 
ing is  dependent  upon  the  size  of  the  model ;  sometimes  it  is  5 
or  6  inches  thick*  and  contains  heavy  battens  of  wood  to  strengthen 
it.  In  less  than  twenty-four  hours  this  coating  is  hard  and  is  taken 
off  the  clay  covering  the  model.  The  coating  thus  removed  is  called 
the  box.f  After  this  the  clay  is  removed  from  the  model  and  the 
model  is  thoroughly  oiled.  The  box  is  oiled  and  put  over  the  model, 
leaving  the  space  between  model  and  box,  formerly  taken  up  by  the 
clay  coating,  a  free  space.  Holes  have  previously  been  made  in  the 
box,  and  over  a  large  center  hole  (sometimes  over  two  or  three,  in 
large  pieces)  a  plaster  funnel  is  placed.  Through  these  funnels 
is  poured  molten  gelatine,  which  fills  every  space,  air  being  allowed 
to  escape  through  small  holes  in  the  box.  In  from  twelve  to  twenty- 
four  hours  the  box  is  again  removed,  placed  hollow  side  up,  and 
the  now  hardened  gelatine  is  removed  from  the  clay  model  and 
placed  in  the  box,  which  it  fits  perfectly.  The  clay  model  has  now 
served  its  purpose,  for  the  gelatine,  which  has  become  a  matrix 
of  the  cast  desired,  is  used  in  the  further  stages  of  the  work.  In 
case  of  large  molds  the  gelatine  matrix  is  sometimes  cut  into  as 
many  as  eight  pieces.  All  these,  of  course,  join  perfectly  in  the 
box  and  are  cast  from  it  as  if  from  a  single  matrix.  The  gelatine 
mold  is  washed  a  number  of  times  with  a  strong  solution  of  water 
and  alum,  and  after  oiling  is  ready  for  the  operation  of  casting. 


*  It  is  generally  i  or  2  inches  thick. 

t  The  term  "case"  is  now  better  understood  in  the  trade. 


8o2 


BUILDING  CONSTRUCTION.        (Ch.  XII> 


The  plaster  for  the  stafif  is  thoroughly  stirred  in  water,  and  the 
hemp,  cut  into  lengths  of  from  6  to  8  inches,  is  bunched  loosely, 
saturated  with  the  plaster  and  put  in  the  molds  in^  a  layer  of  about 

1  inch  in  thickness.  Succeeding  handfuls  of  hemp  are  thoroughly 
interwoven  with  the  preceding,  the  hemp  being  expected  to  fill  in 
all  the  corners  of  the  cast.  When  the  mold  is  filled  the  back  is 
smoothed  over  by  hand,  and  later  the  cast  is  removed  from  the 
mold.  The  time  consumed  from  starting  a  cast  to  removing  it 
from  the  mold  is  about  twenty-five  minutes  for  a  cast  5  feet  by 

2  feet  6  inches  in  size.  After  the  removal  of  the  cast  care  must 
be  exercised  that  it  does  not  collapse  nor  lose  its  form  by  warp- 
ing either  in  standing  it  up  or  in  laying  it  down.  During  the 
summer  months  a  cast  of  the  dimensions  given  will  dry  thoroughly 
in  about  thirty-six  hours  and  is  then  ready  for  application.  In  the 
winter  months  there  is  danger  of  casts  freezing  before  they  are  dry, 
and  in  that  event  they  are  apt  to  go  to  pieces  when  warm  weather 
comes.  A  good  workman  can  make  as  many  as  seventy-five  casts 
in  one  mold,  and  then  the  gelatine  is  remelted  and  a  new  mold 
made  of  it,  the  box  being  good  for  use  for  an  indefinite  length  of 
time.  In  making  pilasters  or  moldings,  etc.,  not  ornamental  or 
under-cut,  plaster  and  wood  molds  are  often  used,  the  latter  material 
being  especially  preferred,  owing  to  its  durability. 

Applied  to  a  frame  building,  staff  is  simply  nailed  on  to  the 
rough  construction,  and  a  cheap  brick  wall  covered  with  it  can,  at 
a  comparatively  small  expense,  be  made  to  assume  a  ''classic*' 
appearance.  In  building  a  brick  house  with  the  employment  of  staff" 
in  view,  it  is  advisable  to  insert  wooden  furring  strips  in  the  brick- 
work, as  these  simplify  the  labor  of  putting  it  on.  For  cornice  work 
it  is  claimed  that  strength  and  boldness  of  design  are  possible  with 
staff  which  cannot  be  realized  with  other  materials. 

At  the  Paris  Exposition  the  buildings  were  constructed  almost 
entirely  of  iron,  and  nearly  all  the  staff  was  cast  in  panels,  which 
were  set  in  iron  frames.  While  this  method  was  considered  excel- 
lent, both  in  finished  effect  and  in  durability,  it  was  far  too  expen- 
sive and  tedious  to  be  employed  in  covering  the  much  more  exten- 
sive structures  to  be  built  for  the  World's  Columbian  Exposition 
in  the  United  States.  Accordingly,  after  many  weeks  of  study,  the 
construction  department  decided  to  construct  the  buildings  of  wood' 
and  to  nail  the  staff  directly  to  the  furring. 


LATHING  AND  PLASTERING. 


803 


The  name  ''staff''  properly  applies  to  material  that  is  cast  in 
molds,  and  not  to  ordinary  plaster  or  cements  that  are  put  on  with 
a  plasterer's  trowel.  Work  with  such  materials  is  subject  to  well- 
understood  limitations  by  the  temperature  and  weather,  but  atmos- 
pheric influences  have  practically  no  effect  upon  staff.  This  has 
been  demonstrated  by  the  acres  of  staff  that  have  been  standing  all 
winter  outside  the  various  casting  shops  in  Jackson  Park.  No 
attempt  has  been  made  to  keep  off  the  rain,  snow  or  frost.  Several 
pieces  of  it  have  been  submerged  for  over  a  month  at  a  time,  allowed 
to  freeze  and  thaw,  and  freeze  again  with  the  water,  and  when 
taken  out  they  were  found  to  be  perfectly  intact. 

While  this  material  admirably  answered  its  purpose  on  the  Fair 
buildings,  it  deteriorated  considerably,  and  evidently  would  not 
answer  in  such  a  climate  for  permanent  buildings  unless  kept  well 
painted.  In  fact,  it  appears  to  be  generally  conceded  that  Portland 
cement  mortar  is  about  the  only  material  that  will  endure  perma- 
nently under  the  trying  condition  of  our  northern  climate.  In 
warmer  and  dryer  climates  compositions  of  plaster  are  largely  used 
on  the  exterior  of  buildings,  and  in  many  instances  they  have  lasted 
for  centuries. 

The  cost  of  ''staff,"  as  used  on  the  Chicago  World's  Fair  build- 
ings, varied  from  $2  to  $2.25  per  square  yard.  Ordinary  cement 
mortar  applied  directly  to  the  walls  cost  about  thirty  cents  per  yard. 

672.  WHITEWASHING.— Although  not  properly  belonging  to 
the  plasterer's  trade,  this  work  is  often  included  in  the  plasterer's 
specifications. 

Common  whitewash  is  made  by  simply  slaking  fresh  lime  in  water. 
It  is  better  to  use  boiling  water  for  slaking.  The  addition  of  2 
pounds  of  suljDiiate  of  zinc  and  i  pound  of  common  salt  for  every 
half-bushel  of  lime  causes  the  wash  to  harden  and  prevents  its 
cracking.-  One  pint  of  linseed  oil,  added  to  a  gallon  of  whitewash 
immediately  after  slaking,  adds  to  its  durability,  particularly  for 
outside  work.  Yellow  ochre,  lampblack,  Indian  red  or  raw  umber 
may  be  used  for  coloring  matter  if  desired. 

Whitewash  not  only  prevents  the  decay  of  wood,  but  conduces 
greatly  to  the  healthfulness  of  all  buildings,  whether  of  wood  or 
stone.  It  does  not  adhere  well,  however,  to  very  smooth  or  non- 
porous  surfaces.  Two  coats  of  whitewash  are  required  on  new  work 
to  make  a  good  job. 


8o4 


BUILDIXG  CONSTRUCTION.        (Ch.  XII) 


673.  LATHING  AND  PLASTERING  IN  FIRE-PROOF 
CONSTRUCTION.— The  lathing  used  in  fire-proof  construction 

has  been  described  in  Article 
479  and  the  immediately  fol- 
lowing- articles.  Metal  laths 
and  the  plastering  on  the  same 
are  also  described  in  Article 
649.  Plasters  as  fire-resisting 
materials  are  treated  of  in 
Article  410.  Lath-and-plaster 
coverings  for  columns  are  dis- 
cussed in  Article  419.  Metal- 
and7plaster  partitions  are  de- 
scribed in  Articles  472  to  478, 
metal  wall  furring  in  Article 
486  and  furring  for  architec- 
tural forms  in  Article  487. 

674,  FRAMES  IN 
METAL  LATH  AND 
PLASTER  PARTITIONS. 
(See  also  Articles  472  to 
478.)  — The  usual  method  of 
framing  for  doors  and  win- 
dows has  been  to  set  up  rough 
wood  frames,  to  which  the 
adjoining  channel  is  securely 
fastened  by  screws  or  anchor 
nails,  and  in  many  cases  this 
method  is  quite  satisfactory. 

Fig.  625  shows  various 
styles  of  door  frames,  which 
differ  principally  in  the  char- 
acter of  the  finish.  Those 
sections  which  have  the  widest 
door  jambs  are  found  to  be 
the  stiffest.  Various  modifi- 
cations of  these  details  may  be  made  to  suit  the  judgment  or  taste 
of  the  architect. 


Door  Frames  in  Metal  Lath  and 
Plaster  Partitions. 


Fig.  626  shows  one  method  of  constructing  the  window  frames 


LATHING  AND  PLASTERING. 


805 


in  corridor  partitions.  The  style  of  molding  may  be  varied  to  suit 
the  taste  of  the  designer. 

In  warehouses  where  there  is  to  be  heavy  trucking,  or  where  iron 
or  fire-proof  doors  are  to  be  used,  the  door  frames  may  be  built  of 
by  i^-inch  angle-irons,  to  which  the  first  stud  of  the  partition 
should  be  rivetted. 

In  extremely  large  doorways  and  on  freight  elevators  it  is  often 
the  custom  to  make  the  frames  of  heavy  2-inch  channel-irons,  to 
which  are  hung  the  large  fire-proof  doors. 

675.  MEASURING  PLASTERWORK.— Lathing  is  always 
figured  by  the  square  yard  and  is  generally  included  with  the  plas- 
tering, although  in  small  country  towns  the  carpenter  often  puts 
on  the  laths. 

Plastering  on  plain  surfaces,  such  as  walls  and  ceilings,  is  always 


Fig. 


626.     Window   Frame   in   Metal   Lath   and  Plaster 
Con-idor  Partition. 


measured  by  the  square  yard,  whether  it  be  one,  two  or  three-coat 
work,  or  whether  it  be  lime  or  hard  plaster. 

In  regard  to  deductions,  for  openings,  custom  varies  somewhat  in 
difi:erent  portions  of  the  country,  and  also  with  different  contrac- 
tors. Some  plasterers  allow  one-half  the  area  of  openings  for 
ordinary  doors  and  windows,  while  others  make  no  allowance  for 
openings  of  less  than  7  square  yards. 

Returns  of  chimney  breasts,  and  pilasters  and  all  strips  less  than 
12  inches  in  width  should  be  measured  as  if  12  inches  wide. 
Closets,  soffits  of  stairs,  etc.,  are  generally  figured  at  a  higher  rate 
than  are  plain  walls  or  ceilings,  as  it  is  not  as  easy  to  get  at  them. 
For  circular  or  elliptical  work,  domes  or  groined  ceilings,  an  addi- 
tional price  is  charged.  If  the  plastering  cannot  be  done  from 
tressels  an  additional  charge  must  be  made  for  staging. 

Stucco  cornices  or  panelled  details  are  generally  measured  by  the 


8o6 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


.  superficial  foot,  measuring  on  the  profile  of  the  -moldings.  When 
less  than  12  inches  in  girth  they  are  usually  rated,  as  i  foot.  For 
each  internal  angle  i  lineal  foot  should  be  added,  and  for  external 
angles  2  feet. 

For  cornices  on  circular  or  elliptical  work  an  additional  price 
should  be  charged. 

Enriched  moldings  are  generally  figured  by  the  lineal  foot,  the 
price  depending  upon  the  design  and  size  of  the  molding. 

Whenever  plastering  is  done  by  measurement  the  contract  should 
state  definitely  whether  or  not  openings  are  to  be  deducted ;  and  a 
special  price  should  be  made  for  the  stuccowork,  based  on  the 
full-size  .details. 

676.  QUANTITIES  OF  MATERIALS  AND  COST  OF 
PLASTERWORK. — The  cost  of  lime  plastering  on  plain  surfaces, 
including  wooden  laths,  varies  from  thirty  to  fifty-five  cents  per 


Description  of  Work.  ^ 


Lime  Mortar : 

1  Two-coat  work  on  brick  or  tile  

1  Three-coat  work  on  wood  laths  

1  Three-coat  work  on  stiffened  wire  lath  3. .   

1  Three-coat  work  on  expanded  metal.^  

2  Rock  Plaster,  W^indsor  Cement  or  Adamant  on  brick  or  tile . 

2  Acme  or  Royal  cement  plaster  on  brick  or  tile  

2  Windsor  Cement  or  Adamant  on  stiffened  wire  lath  ^  

2  Rock  Plaster,  Acme  or  Royal  cement  plaster  on  stiffened 

wire  lath  ^  

Cost  of  stiffened  wire  lath  on  wood  joists,  about  

Cost  of  expanded  metal  on  wood  joists  

Cost  of  Bostwick  last  on  wood  joists  

Stucco  cornices,  less  than  12  inches  girth,  per  lineal  foot  

When  more  than  12  inches  girth,  cost  per  square  foot  

Enrichments  cost  from  8  cents  up,  per  lineal  foot,  for  each 
member. 


1  The  last  coat  to  be  white  finish. 

2  Finished  with  lime  putty  and  plaster. 

3  When  applied  on  wood  joists  or  furring:  when  applied  over  metal  furrings  the 
cost  is  about  20  cents  per  yard  more.   The  price  includes  the  cost  of  the  metal  lath. 


yard,  according  to  the  times,  locality,  number  of  coats  and  quality 
of  work.  For  ordinary  three-coat  work,  with  white  finish,  thirty- 
five  or  forty  cents  is  probably  about  the  average  price  for  the  entire 
country.  The  author  has  known  at  various  times  in  the  past  very 
good  work  to  be  done  for  twenty  cents  per  yard,  but  at  that  price 
there  was  no  profit  above  the  wages  of  the  men. 

Hard  plasters  cost  from  two  to  ten  cents  per  yard  more  thaa 


Average  cost  in  cents 
per  square  yard. 


New  York. 

St.  Louis.* 

30  to  40 

25 

45  to  55 

25  to  35 

70 

60 

40 

40 

25  to  30 

75 

75 

65 

35 

25  to  35 

35 

25  to  35 

35 

20  to  40 

20  to  40 

25  to  30 

25  to  30 

*  These  prices  are  about  the  average  asked  in  the  West. 


LATHING  AND  PLASTERING. 


807 


lime  plaster,  according  to  the  price  of  lime  and  the  freightage  on 
the  hard  plaster. 

Wire  lathing  or  metal  lathing  costs  from  twenty-five  to  forty  cents 
per  yard  more  than  the  cost  when  wood  laths  are  nsed. 

The  figures  in  the  table  on  the  preceding  page  give  the  average 
prices  for  various  kinds  of  plastering  in  the  cities  of  New  York 
and  St.  Louis,  subject  to  variations  from  year  to  year: 

For  the  scratch  coats  and  brown  coats  on  wood  laths,  with 
^-inch  grounds,  the  following  quantities  of  materials  are  required 
for  100  square  yards:  From  1.400  to  1,500  laths,  10  pounds  of 
threepenny  nails,  tw^o  and  one-half  casks  or  500  pounds  of  lime, 
.45  cubic  feet  or  fifteen  casks  of  sand  and  four  bushels  of  hair. 

For  the  best  quality  of  white  coating  allow  90  pounds  of  lime, 
50  pounds  of  plaster  of  Paris  and  50  pounds  of  marble  dust. 

It  is  impossible  to  quote  prices  which  will  hold  for  the  many 
different  parts  of  the  United  States,  and  those  given  are  only 
approximate.  They  give  some  idea,  however,  of  relative  values. 
The  following  data*  relating  to  quantities  of  materials  and  cost  of 
lathing  and  plastering  are  added.  They  include  some  of  the  items 
already  given,  and  vary  in  some  particulars,  being  compiled  from 
other  sources. 

Quantities  of  Materials  Required  for  Lathing  and  Plastering. — 
To  cover  100  square  yards  requires  from  1,400  to  1,500  laths 
(about  1,450  for  an  average  job)  and  10  pounds  of  threepenny 
nails. 

Three-coat  plastering  on  wood  laths,  plaster  of  Paris  finish, 
requires  from  8  to  10  bushels  of  lime,  yards  of  sand,  2  bushels 
of  hair  and  100  pounds  of  plaster  of  Paris  per  100  square  yards. 

If  the  finishing  coat  is  omitted  deduct  2  bushels  of  lime  and  all 
of  the  plaster  of  Paris. 

If  a  sand-finish  is  required  omit  the  plaster  of  Paris  and  add  ^ 
a  yard  of  sand. 

Two  coats  on  brick  or  stone  walls  (brown  coat  and  finishing 
coat)  require  from  6  to  8  bushels  of  lime,  yards  of  sand  and 
100  pounds  of  plaster  of  Paris  to  100  square  yards. 

Best's  Keene's  cement  for  brown  mortar  and  Keene's  finish  on 
expanded-metal  lath  requires,  for  the  brown  mortar,  550  pounds 
of  cement,  5^  bushels  of  lime,  2  yards  of  sand  and  2  bushels  of 

*  Taken  from  Part  III  of  the  "Architect's  and  Builder's  Pocket-Book."  Frank  E. 
Kidder. 


8o8 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


hair;  and  for  the  finish,  300  pounds  of  cement  and  i  bushel  of 
lime  per  100  yards. 

Hard  plasters  on  expanded-metal  lath,  plaster  of  Paris  finish, 
require  for  the  brown  mortar  2,000  pounds  of  plaster  and  2  yards 
of  sand;  for  the  finish,  i  bushel  of  lime  and  100  pounds  of  plaster 
of  Paris  per  100  yards. 

Cost. — The  standard  price  for  putting  on  wood  laths  (labor 
only),  in  Denver,  is  3^  cents  per  yard.  For  expanded-metal  or 
sheet-metal  lath  on  wood  studding,  5  cents ;  on  steel  studding,  wired, 
8  cents. 

The  cost  of  putting  three  coats  on  laths,  plaster  of  Paris  finish 
(labor  only),  is  about  15  cents  per  yard  for  drawn  work  and  16 
cents  for  dry  scratched  work. 

For  sand  finish  the  cost  is  about  the  same  as  for  white  finish. 

These  figures  are  based  on  plasterers'  wages  at  62^  cents  per 
hour  and  on  hod-carriers'  and  mortar-mixers'  wages  at  373^  cents 
per  hour. 

The  following  table  gives  the  average  cost  of  dififerent  kinds 
of  plastering  in  Denver,  based  on  Missouri  lime  at  40  cents  per 
bushel,  sand  at  75  cents  per  load  of  1%  yards,  hair  at  40  cents 
per  bushel,  plaster  of  Paris  at  50  cents  per  100  pounds  and  wages 
as  given  above : 

Scratch  and  brown  coat  (lime)  on  wood  laths.  .  25  cents  per  yard., 
3  coats  (lime)  on  wood  laths,  plaster  of  Paris 

finish   30     "  " 

3  coats  (lime)  on  wood  laths,  sand  finish   30      "      "  " 

Brown  coat  and  finish  on  brick  walls   23      "  " 

For  hard  wall  plaster  instead  of  lime,  add.....    3      "      "  " 
3  coats  (lime),  plaster  of  Paris  finish,  metal  lath 

on  wood  studding   65  "  " 

3  coats  (lime)  plaster  of  Paris  finish,  metal  lath 

on  steel  studding  '. .  .  68 

For  Keene's  cement  finish,  add   10      "  " 

For  blocking  in  imitation  of  tile,  add.  ...  50     "      "  " 
2  coats  hard  wall  plaster,  plaster  of  Paris  finish, 

metal  lath,  wood  studding   70     "  " 

2  coats  hard  wall  plaster,  plaster  of  Paris  finish, 

metal  lath  on  steel  studs   73     "     "  " 

For  Keene's  cement  finish,  add   10     "     "  " 


LATHING  AND  PLASTERING. 


Portland    cement,    brown    coat,    finished  with 

Keene's  cement  blocked  in  imitation  of  tile, 

3  by  6  inches   $2.80  per  yard. 

For   running  base,  9   inches   high,   in  Best's 

Keene's  cement    10  cents  per  foot. 

For  running  plain  moldings  in  plaster  of  Paris,  from  3  to  5  cents 

per  inch  of  girth. 
For  finishing  shafts  of  columns,  from  16  to  24  inches  in  diameter 

and  from  12  to  14  feet  in  height,  $3.00  per  column  (labor  only). 

These  prices  are  believed  to  be  pretty  nearly  an  average  for  the 
entire  country.  In  some  localities  prices  for 'materials  or  labor  are 
less,  in  others  more. 

677.  COLORED  SAND  FINISH.— In  most  instances  where 
sand  finish  is  used  on  interior  walls,  it  is  for  the  purpose  of  after- 
ward decorating  with  water  colors.  In  such  cases  the  finish  itself 
may  be  colored  or  stained  at  a  slightly  less  expense  than  is  required 
for  water  colors.  When  the  finish  is  stained  throughout  its  entire 
mass,  dents  and  scratches  do  not  show,  as  they  do  in  the  case  of 
paint  or  kalsomine.  For  coloring  sand  finish,  pulp  stains  of  the 
best  quality  should  be  used.  These  are  mixed  with  water  to  the 
consistency  of  a  thick  cream  and  then  thoroughly  mixed  with  the 
finishing  material,  all  the  mortar  for  one  room  being  mixed  at  one 
time,  so  that  the  color  will  be  uniform.  No  plaster  of  Paris  should 
be  used  in  colored  sand  finish,  as  it  will  streak  the  wall.  Dry  colors 
also  should  not  be  used,  as  they  are  quite  sure  to  prove  a  failure. 
(See  also  Article  657,  under  ''Sand  Finish.") 

678.  SUPERINTENDENCE  OF  LATHING  AND  PLAS- 
TERING.— This  consists  chiefly  in  seeing  that  the  work  is  per- 
formed in  accordance  with  the  specifications ;  and  if  the  specifica- 
tions are  properly  written  much  of  the  vexation  of  superintendence 
is  saved.  The  details  which  the  superintendent  should  particularly 
inspect  are  the  following: 

Quality  of  Materials. — See  that  the  laths  are  of  the  kind  specified, 
and,  if  of  wood,  that  they  are  free  from  bark  and  dead  knots.  If 
any  such  laths  have  been  put  on  have  them  removed  and  have  clean, 
sound  laths  substituted.  See  that  the  lime  is  of  the  kind  specified; 
if  it  is  not  in  casks  it  is  well  to  require  the  plasterer  to  pro- 
duce the  bills  for  it ;  also  see  that  the  lime  is  fresh  and  in 
good  condition.    Permit  no  lime  that  has  commenced  to  slake  to  be 


8io 


BUILDING  CONSTRUCTION.        (Ch.  XII) 


used.  Inspect  the  sand  to  see  that  it  is  free  from  earthy  matter, 
and  that  it  is  properly  screened.  Make  a  note  of  the  time  when 
the  plasterer  commences  to  make  the  mortar,  and  do  not  permit 
him  to  use  it  until  it  is  at  least  seven  days  old,  or  as  old  as  required 
by  the  specifications. 

As  to  the  proportions  of  the  lime,  sand  and  hair,  not  much  can  be 
determined  by  the  superintendent,  unless  he  has  the  quantities 
measured  in  his  presence,  a  proceeding  which  requires  his  being  on 
the  ground  most  of  the  time.  Something,  however,  of  the  quality 
of  the  mortar  and  of  the  amount  of  hair  may  be  determined  by 
trying  the  former  wjth  a  trowel.  The  superintendent  should 
endeavor  to  make  himself  familiar  with  the  appearance  of  good 
mortar.  He  should  see  that  the  hair  is  mixed  with  the  mortar  at 
the  stage  specified,  and  should  in  no  case  permit  it  to  be  mixed  with 
the  hot  lime. 

Lathing. — Before  the  workmen  commence  to  put  on  the  laths  the 
architect  or  superintendent  should  carefully  examine  all  grounds 
and  furring  to  see  that  they  are  in  the  right  place  and  that  they  are 
plumb  and  square.  If  the  chimney-breasts  are  furred,  as  they 
usually  are  in  the  Eastern  States,  they  should  be  tried  with  a  car- 
penter's square  to  make  sure  that  their  external  and  internal  angles 
are  right-angles;  and  to  see  also  that  all  angles  of  adjoining  par- 
titions are  made  solid,  so  that  there  can  be  no  lathing  through  these 
angles. 

If  wooden  laths  are  used  see  that  they  are  well  nailed  and  that 
they  are  not  placed  too  near  together;  ^  of  an  inch  should  be 
allowed  on  ceilings  and  from      to  i%  of  an  inch  on  walls. 

See  that  the  end  joints  are  broken  at  least  every  i8  inches ;  or, 
better  still,  have  the  joints  broken  at  every  course. 

See  that  the  laths  over  door  and  window  heads  extend  at  least  to 
the  next  stud  beyond  the  jamb  (as  in  Fig.  627),  so  as  to  prevent 
cracks  which  are  apt  to  appear  at  that  point ;  see  also  that  all  the 
laths  run  in  the  same  direction.  When  laths  run  in  -difYerent  direc- 
tions (as  in  Fig.  628)  cracks  are  sure  to  appear  where  the  change 
in  direction  takes  place.  See  that  all  recesses  in  brick  walls  for 
pipes,  etc..  are  covered  with  wire  lath  or  expanded-metal  lathing, 
unless  they  are  to  be  covered  with  boards. 

See  that  all  wood  lintels  and  other  solid  timbers  that  are  not 
furred  are  covered  with  metal  lath.    The  joints  also  between  wood- 


LATHING  AND  PLASTERING. 


8ii 


work  and  brickwork  should  be  covered  with  metal  lathing.  If  any 
kind  of  metal  lathing  is  used  see  that  it  is  put  up  as  directed  by 
the  manufacturers,  and  that  all  wire  lathing  is  tightly  stretched; 
see  that  the  furrings  are  properly  spaced  and  that  the  whole  is  well 
secured. 

Closing  the  Building. — Before  the  plasterers  c(jmmence  work  the 
superintendent  should  see  that  the  building  is  closed  up  by  the  car- 
penter, by  filling  the  openings  with  boards,  old  sashes  or  cloth. 
Cotton  cloth  is  the  best  material  for  the  purpose,  as  it  allows  some 
circulation  of  air  through  it. 

Heating  the  Building. — If  the  plastering  is  done  in  cold  or  freez- 
ing weather  provision  must  be  made  for  heating  the  building. 
Ordinary  lime  plaster  is  completely  ruined  by  freezing  and  thawing, 


Fig.   628.     Lathing   Run  in 
Two   Directions.  Poor 
Construction. 


and  plastering  that  has  been  once  frozen  will  never  become  hard 
and  solid. 

Plastering. — When  the  scratch  coat  is  partly  on, , the  superinten- 
dent should  try  to  look  behind  the  laths  to  see  if  the  mortar  has 
been  well  pushed  through  between  them,  as  the  clinch,  or  key,  at 
the  back  of  the  laths  is  all  that  holds  the  plaster  in  place. 

See  that  the  first  coat  is  dry  before  the  second  is  put  on,  if  so 
specified ;  see  also  tha^  the  surface  of  the  brown  coat  is  brought  to 
a  true  plane,  the  angles  made  straight  and  square,  the  walls  plumb 
and  the  ceilings  level.  The  specifications  should  require  that  the 
first  and  second  coats  be  carried  to  the  floor,  behind  the  base  or 
wainscoting. 

When  brick  walls  are  to  be  plastered  the  superintendent  should 


8l2 


BUILDING  CONSTRUCTION.        (Ch.  XII> 


remember  that  a  much  firmer  job  of  plastering  will  be  obtained  if 
the  wall  is  well  wet  just  before  the  plastering  is  applied. 

If  the  first  and  second  coats  have  been  properly  put  on' the  finish- 
ing coat  will  need  little  superintendence  beyond  seeing  that  proper 
materials  are  used  and  that  the  work  is  well  trowelled,  if  it  is  to 
be  a  hard  finish. 

If  any  of  the  improved  plasters  described  in  Articles  658  to  663 
are  used  the  superintendent  should  see  that  the  instructions  fur- 
nished by  the  manufacturers  are  strictly  followed,  particularly  as  to 
the  wetting  of  the  laths  and  the  proportion  of  sand  to  be  used ;  he 
should  see  also  that  no  mortar  that  haS  commenced  to  set  is 
remixed.  When  machine-made  lime  mortar  or  any  of  the  hard 
plasters  that  are  sold  already  mixed  with  sand  and  fiber  are 
specified  the  care  of  superintendence  is  greatly  lessened.  If 
improved  plasters  are  used  in  freezing  weather  the  temperature  of 
the  building  must  be  kept  above  the  freezing  point  until  the  plaster 
has  set. 


Chapter  XIII. 

Specifications^ 


679,  GENERAL  CONSIDERATIONS.— The  specifications  for 
any  particular  piece  of  work  should  be  considered  as  of  equal 
importance  with  the  drawings.  The  architect  should  not  expect  the 
contractor  to  do  anything-  not  provided  for  by  the  plans  and  speci- 
fications without  extra  compensation,  nor  to  do  the  work  better 
than  the  specifications  call  for.  He  must  therefore  be  sure  that 
everything  which  he  wishes  done  is  clearly  indicated  either  by  the 
plans  or  specifications,  and  that  no  loopholes  are  allowed  for  poor 
workmanship  or  inferior  materials.  The  portions  of  the  work  to- 
be  done  by  each  contractor  should  also  be  clearly  stated,  so  that: 
there  can  be  no  misunderstanding  as  to  which  contractor  is  to  do- 
certain  portions  of  the  work.  It  very  often  happens  that  some 
minor  details,  such  as  the  closing  up  of  the  windows,  the  protectioni 
of  stonework,  etc.,  are  not  properly  specified,  and  the  contractors 
dispute,  much  to  the  annoyance  of  the  architect,  as  to  which  one 
shall  do  that  part  of  the  work.  Such  annoyances  are  largely 
avoided  when  the  entire  contract  for  the  erection  and  completion 
of  the  building  is  given  to  one  person  or  firm ;  but  even  then  it  is; 
better  to  have  the  duties  of  the  subcontractors  clearly  defined. 

As  a  rule,  the  form,  dimensions  and  quantity  of  all  materials 
should  be  fully  indicated  on  the  drawings,  so  that  only  the  kind 
and  quality  of  the  materials  and  the  manner  of  doing  the  work 
need  be  given  in  the  specifications.  General  clauses  should  be 
avoided  as  far  as  possible,  as  they  only  cumber  the  specifications 
and  tend  to  obscure  the  really  important  portions. 

The  following  forms  of  specifications  for  various  kinds  of  mason- 
work  are  given  merely  as  guides  or  reminders  for  architects,  and 
not  as  models  always  to  be  copied  literally.  Figures  or  words 
enclosed  in  parentheses^  (  ),  may  be  changed  to  suit  special  or 
local  conditions. 

Every  specification  should  be  prepared  with  special  reference  to- 
the  particular  building  for  which  it  is  intended. 

813 


8i4 


BUILDING  CONSTRUCTION. 


(Ch.  xrri) 


The  use  of  standard  specifications  is  not  recommended,  because 
when  such  specifications  are  adopted  the  architect  is  more  apt  to 
overlook  important  details ;  and  the  use  of  such  forms,  moreover, 
tends  to  prevent  progressiveness  and  study  of  the  construction  best 
suited  to  the  varying  circumstances  of  different  buildings. 

The  author  would  recommend  to  the  young  architect  that  before 
commencing  to  write  or  dictate  his  specifications  he  make  a  skeleton 
•outline,  consisting  of  headings  of  the  different  items  to  be  specified, 
carefully  looking  over  the  plans  and  revising  the  outline  until 
everything  seems  to  be  covered  and  the  headings  arranged  in  their 
proper  sequence.  The  specifications  can  then  be  filled  out  in  the 
manner  indicated  in  the  following  articles. 

GENERAL  CONDITIONS. 

680.  Every  specification  should  be  preceded  by  the  general  con- 
'ditions  governing  all  contractors.  These  are  sometimes  printed  on 
a  separate  sheet  and  used  as  a  cover  for  the  written  specification. 
In  this  case  they  should  not  be  repeated  in  the  latter. 

The  general  conditions  used  vary  more  or  less,  according  to  the 
judgment  and  experience  of  different  architects. 

The  following  form  has  been  used  by  the  author  for  a  number  _ 
.of  years  with  satisfactory  results : 

GENERAL  CONDITIONS.— The  contractor  is  to  give  his  per- 
sonal superintendence  and  direction  to  the  work,  keeping,  also,  a 
competent  foreman  constantly  on  the  ground.  He  is  to  provide 
all  labor,  transportation,  materials,  apparatus,  scaffolding  and 
utensils  necessary  for  the  complete  and  substantial  execution  of 
everything  described,  shown  or  reasonably  implied  in  the  drawings 
and  specifications. 

All  materials  and  workmanship  are  to  be  of  the  best  quality 
throughout. 

The  contractor  is  to  carefully  lay  out  his  work  and  be  respon- 
sible for  any  mistakes  he  may  make  and  any  injury  to  others  result- 
ing from  them. 

Where  no  figures  or  memoranda  are  given  the  drawings  are  to 
be  accurately  followed  according  to  their  scale ;  but  figures  or 
memoranda  are  to  be  preferred  to  the  scale  measurements  in  all 
cases  of  difference. 

In  aiiy  and  all  cases  of  discrepancy  in  figures  the  matter  is  to  be 


GENERAL  CONDITIONS. 


8iS 


immediately  submitted  to  the  architect  for  his  decision,  and  without 
such  decision  said  discrepancy  is  not  to  be  adjusted  by  the  con- 
tractor save  and  only  at  his  own  risk ;  and  in  the  settlement  of  any 
complications  arising  from  such  adjustment,  the  contractor  is  to 
bear  all  the  extra  expenses  involved. 

The  plans  and  these  specifications  are  to  be  considered  co-opera- 
tive ;  and  all  works  necessary  to  the  completion  of  the  design,  drawn 
on  plans,  and  not  described  herein,  and  all  works  described  herein 
and  not  drawn  on  plans,  are  to  be  considered  a  portion  of  the  con- 
tract, and  must  be  executed  in  a  thorough  manner,  with  the  best  of 
materials,  the  same  as  if  fully  specified. 

The  architect  will  supply  full-size  drawings  of  all  details,  and 
any  work  constructed  without  such  drawings,  or  not  in  accordance 
with  them,  is  to  be  taken  down  and  replaced  at  the  contractor's 
expense. 

Any  inaterial  delivered  or  work  erected  not  in  accordance  with 
the  plans  and  these  specifications  is  to  be  removed  at  the  contractor's 
expense  and  replaced  with  other  material  or  work,  satisfactory  to 
the  architect,  at  any  time  during  the  progress  of  the  work.  Or  in 
case  the  nature  of  the  defects  is  such  that  it  is  not  expedient  to  have 
them  corrected,  the  architect  shall  have  the  right  to  deduct  such 
sums  of  money  as  he  considers  a  proper  equivalent  for  the  difiference 
between  the  value  of  the  materials  or  work  furnished  or  executed' 
and  the  value  of  the  materials  or  work  specified,  or  a  proper 
equivalent  for  the  damage  to  the  building,  from  the  amount  due 
the  contractor  on  the  final  settlement  of  the  accounts. 

The  contractor  is  to  provide  proper  and  sufficient  safeguards 
against  and  protection  from  any  accidents,  injuries,  damages  or 
hurt  to  any  person  or  property  during  the  progress  of  the  work  ; 
and  he  alone  is  to  be  responsible,  and  not  the  owner  or  the  archi- 
tect, who  is  not  to  be  answerable  in  any  manner  for  any  loss  or 
damage  that  mav  happen  to  the  work,  or  to  any  part  thereof,  or 
for  any  of  the  materials  or  tools  used  and  employed  in  finishing 
and  completing  the  work. 

The  contractor  is  to  produce,  when  called  upon  by  the  architect, 
vouchers  from  the  subcontractors  to  show  that  the  work  is  being 
paid  for  as  it  proceeds. 

All  facilities,  such  as  ladders,  scaffolding  and  gangways,  are  to  be 
afforded  the  architect  for  inspecting  the  building  in  safety,  and  pro- 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


vision  is  to  be  made  to  the  architect's  satisfaction  for  protection  from 
falling  materials. 

The  drawings  are  the  property  o"f  the  architect  and  must  be 
returned  to  him  before  the  final  payment  is  made. 

The  contractor  is  to  keep  the  building  at  all  times  free  from  rub- 
bish of  all  kinds,  and  on  the  completion  of  the  work  of  the  contract 
is  to  remove  all  rubbish  and  waste  material  caused  by  any  operations 
under  his  charge,  clean  out  the  building  and  grounds  and  leave  the 
work  perfect  in  every  respect. 

EXCAVATING  AND  GRADING. 

68 1.  The  contractor  is  to  visit  the  site  of  the  building,  examine 
for  himself  the  condition  of  the  lot  and  satisfy  himself  as  to  the 
nature  of  the  soil. 

[Where  this  is  not  practicable  the  architect  should  show  the  pres- 
ent grade  of  lot  by  red  lines  on  the  elevation  drawings,  and  the 
nature  of  the  soils  should  be  determined  by  borings  or  test-pits. 
See  Article  5.] 

Loam. — This  contractor  is  to  remove  the  present  top  soil  to  the 
depth  of  12  inches  from  the  site  of  the  building  and  to  a  distance 
of  (20)  feet  on  each  side,  and  stack  it  on  the  lot  where  indicated. 

Excavations  are  to  be  made  to  the  depth  shown  by  the  drawings 
for  the  cellar,  areas,  coal  vault  and  outside  entrance,  and  for 
trenches  under  all  walls  and  piers.  All  trenches  are  to  be  excavated 
to  the  neat  size  as  far  as  practicable,  and  each  is  to  be  levelled 
to  a  line  on  the  bottom,  ready  to  receive  the  foundations.  This  con- 
tractor must  be  careful  not  to  excavate  the  trenches  below  the  depth 
shown  by  the  drawings ;  should  he  do  so  he  is  to  pay  the  mason 
for  the  extra  masonwork  thereby  made  necessary,  as  under  no  con- 
dition will  dirt  filling  be  allowed. 

All  excavations  are  to  be  kept  at  least  (12)  inches  outside  the 
outer  face  of  walls.  (See  Article  35.) 

[Excavations  for  drains,  dry  wells,  furnace-pit,  air-ducts,  etc., 
are  to  be  specified  here  if  required.] 

Water. — If  water  is  encountered  in  making  the  excavations,  this 
contractor  is  to  keep  it  pumped  out  of  the  way  until  the  footings 
are  set,  unless  it  is  practicable  to  drain  it  into  the  sewer. 

Rock. — If  a  solid  ledge  of  rock  is  encountered  in  the  excavations, 
this  contractor  is  to  remove  the  same  by  blasting  or  other  process. 


WOODEX  PILING. 


817 


and  is  to  pile  the  stone  on  the  lot  where  directed  (if  it  is  suitable 
for  the  foundation  work).    For  removing  such  rock  an  extra  sum 

•of  (   cents)  per  cubic  foot  of  rock  excavation  is  to  be  paid, 

but  no  extra  payment  is  to  be  made  for  removing  boulders  or  loose 
stones. 

All  material,  except  the  loam  and  such  material  as  may  be  needed 
for  filling  in  about  the  walls  (or  for  grading),  is  to  be  removed 
from  the  premises  as  soon  as  excavated. 

Filling  In. — When  directed  by  the  architect,  this  contractor  is  to 
fill  in  about  the  walls  (with  stone,  gravel  or  sand)  to  within  (3) 
feet  (half  their  height)  of  the  finished  grade;  and*  as  soon  as  the 
first  floor  joists  are  set  he  is  to  complete  the  fihing  to  the  grade 
line,  tamping  the  earth  solidly  every  6  inches.    (See  Article  125.) 

Grading. — The  surface  of  the  lot  is  to  be  graded  to  the  level 
indicated  by  the  drawings  (using  the  loam  first  removed)  and  it 
is  to  be  left  in  good  condition  for  top  dressing  (or  for  paving). 
(Foundations  for  walks  and  driveways.) 

[When  building  on  a  site  formerly  occupied  by  another  structure, 
or  covered  with  rubbish,  the  specifications  should  provide  for  the 
removal  of  all  rubbish,  debris,  old  foundation  stone,  sidewalk  stone 
and  other  materials  that  cannot  be  used  in  the  new  building.] 

WOODEN  PILING. 

682.  This  contractor  is  to  furnish  and  drive  the  piles  indicated 
on  sheet  (i). 

All  wooden  piles  are  to  be  of  sound  (white  oak,  yellow  pine,  Nor- 
way pine  or  spruce).  They  are  to  be  at  least  (6)  inches  in  diameter 
at  the  smaller  end  and  (10)  inches  in  diameter  at  the  butt  when 
sawn  ofif,  and  are  to  be  perfectly  straight  and  trimmed  close  and 
are  to  have  the  bark  stripped  ofif  before  they  are  driven.* 

The  piles  are  to  be  driven  into  hard  bottom  or  until  they  do  not 
move  more  than  an  inch  under  the  blow  of  a  hammer  weighing 
(2,000)  pounds,  falling  (25)  feet  at  the  last  blow.  They  are  to  be 
driven  vertically  and  at  the  distances  apart  required  by  the  plans. 

They  are  to  be  cut  off  square  at  the  head,  and,  when  necessary  to 
prevent  brooming,  are  to  be  bound  with  iron  hoops. 

All  piles,  when  driven  to  the  required  depth,  are  to  be  cut  off  by 


*  This  latter  clause  is  not  always  inserted. 


8i8 


BUILDING  CONSTRUCTION,       (Ch.  XIII) 


this  contractor,  square  and  horizontally  and  at  the  grade  indicated 
on  the  drawings.    (See  Articles  40  to  45.) 

CONCRETE  FOOTINGS. 

683.  All  footings  colored  (purple)  on  the  foundation  plans  and 
sections  are  to  be  constructed  of  concrete  furnished  and  put  in 
place  by  this  contractor. 

If  the  trenches  are  not  excavated  to  the  neat  size  of  the  footings, 
or  if  the  concrete  is  above  the  level  of  cellar  floor,  this  contractor 
is  to  set  up  2-inch  planks  supported  by  stakes  or  solidly  banked  with 
earth  to  confine  the  concrete ;  and  these  planks  are  not  to  be  removed 
until  the  concrete  is  (48)  hours  old. 

The  concrete  is  to  be  composed  of  first-quality  fresh  cement, 

clean,  sharp  sand  and  clean  (granite)  broken  to  a  size  that  will  pass 
through  a  2^-inch  ring,  and  thoroughly  screened.  These  ingre- 
dients are  to  be  used  in  the  proportion  of  i  part  of  cement,  2  of 
sand  and  4  of  stone,  and  mixed  each  time  by  careful  measurement,  in 
the  following  manner :  On  a  tight  platform  of  planks  four  barrows 
of  sand  are  to  be  spread,  and  upon  this  two  barrows  of  cement. 
These  two  materials  are  to  be  thoroughly  dry-mixed,  and  on  them 
are  to  be  "thrown  eight  barrows  of  broken  stone  and  the  whole 
worked  over  again ;  the  mixture  is  to  be  then  worked  thoroughly 
and  rapidly  with  shovels  while  water  is  being  thrown  on  from  a 
hose,  until  every  stone  is  completely  covered  with  mortar.  No  more 
water  is  to  be  used  than  is  necessary  to  thoroughly  unite  the 
materials.  As  soon  as  the  concrete  is  mixed  it  is  to  be  taken  to 
the  trenches,  dumped  in  in  layers  about  6  inches  thick  and  imme- 
diately rammed  until  the  water  flushes  to  the  top.  Each  layer  is 
to  be  deposited  before  the  preceding  one  becomes  dry,  and  in  each 
case  the  top  surface  is  to  be  well  wet  before  a  new  layer  is  put  in. 
The  stone  footings  are  not  to  be  put  on  the  concrete  until  it  is 
two  days  old.    (See  Articles  499  to  502.) 

[On  large  and  important  work  the  specifications  should  also  pro- 
vide for  testing  the  cement.  (See  Articles  498  to  502.)  The  above 
quantities  are  as  large  as  should  be  used  for  any  one  mixing.] 

SPECIFICATIONS  FOR  STONEWORK. 

684.  FOOTINGS. — Supported  on  Wooden  Piles. — The  wooden 
pile  cappings  are  to  be  of  evenly  split  granite  blocks  (16)  inches  thick 


STOXEJVORK. 


819 


from  the   quarries,  and  are  to  be  of  such  sizes  that  no  stone 

will  rest  on  more  than  three  piles.  These  stones  are  to  be  bonded 
as  shown  on  the  special  drawings.  Each  and  every  stone  is  to  be 
carefully  wedged  up  with  oak  wedges  on  the  head  of  each  pile  to 
secure  a  firm  and  equal  bearing,  and  piles  and  cappings  are  to  butt 
closely  together. 

Dimension  Footings. — The  footings  under  all  outside  foundation 

walls  are  to  consist  of  dimension-stone  from  the  or   

quarries,  of  the  width  shown  on  the  section  drawings  and  (12) 
inches  in  thickness.  The  stones  are  to  have  fair  top  and  bottom 
surfaces  and  are  to  be  bedded  and  puddled  in  cement  mortar.  No 
footing  stone  is  to  be  less  than  (3)  feet  long. 

Rubble  Foofifigs. — The  footings  under  (all  other)  foundation 
walls  are  to  be  built  the  width  and  thickness  shown  on  section 

drawings,  of    stone.    The  stonework  is  to  be  heavy  rubble 

and  each  stone  is  to  be  the  full  thickness  of  the  footing  course  and 
at  least  2  feet  6  inches  long,  and  there  are  to  be  not  more  than  two 
stones  abreast  in  the  width  of  the  wall.  There  is  to  be  one  through 
stone  also,  the  full  width  of  the  footings,  every  (6)  lineal  feet. 
Each  stone  is  to  be  solidly  bedded  and  puddled  in  cement  mortar, 
and  all  chinks  between  the  stones  are  to  be  filled  up  solid  with 
mortar  and  spalls. 

685.  FOUNDATION  WALLS.— Bloek  Granite  or  Limestone. 
— The  foundation  walls  colored  (blue)  on  plans  are  to  be  built  to 
the  height  and  of  the  thickness  shown  on  section  drawings,  of 
sound,  evenly  split  granite  (limestone)  blocks  averaging  (3)  feet 
in  length  and  (18)  inches  in  width;  and  these  stones  are  to  be  not 
less  than  (12)  inches  in  height.  They  are  to  be  laid  with  a  good 
bond  in  regular  courses,  as  near  as  can  be,  and  to  be  bonded  with 
one  through  stone  to  every  (10)  square  feet  of  wall. 

The  stones  are  to  be  laid  in  cement  mortar,  as  described  else- 
where, and  all  chinks  and  voids  are  to  be  filled  with  slate  or  (granite) 
spalls  and  mortar;  they  are  to  show  a  good  straight  face  where 
exposed  in  the  basement  and  the  joints  are  to  be  neatly  pointed  with 
the  trowel.  All  walls  are  to^e  built  to  a  line  both  inside  and  outside 
and  all  angles  are  to  be  plumb.  (The  inside  face  of  the  wall  is  to 
be  hammer-dressed.)  The  top  of  the  wall  is  to  be  carefully  levelled 
for  the  superstructure  with  heavy  stones  at  each  corner.  Holes  are 
to  be  left  in  the  walls  for  drain  pipes,  gas  pipes  and  water  pipes. 


820 


BUILDIXG  COXSTRUCTIOX 


(Ch.  XIII) 


Rubble  Walls. — The  foundation  and  basement  walls  colored 
(gray)  on  plans  are  to  be  built  to  the  height  and  of  the  thickness 

shown  on  section  drawings,  of  stone  rubble  work.    The  stones 

are  to  be  selected,  large-size,  first-quality  stones,  laid  to  the  lines  on 
both  sides,  well  fitted  together,  and  with  all  voids  filled  up  solid 
with  spalls  and  mortar.  Each  stone  is  to  be  firmly  bedded  and 
cushioned  into  place  and  all  joints  are  to  be  filled  with  mortar.  The 
width  of  at  least  one-half  of  the  stones  is  to  be  two-thirds  that  of 
the  wall,  and  there  is  to  be  one  through  stone  to  every  (lo)  square 
feet  of  wall.  The  larger  part  of  the  stones  are  to  be  not  less  than 
(2  feet)  long,  (16  inches)  wide  and  (8  inches)  thick.  The  wall 
is  to  be  laid  in  courses  about  (18  inches)  high  and  levelled  off  at 
each  course.*  (Each  stone  is  to  have  hammer-dressed  beds  and 
joints,  and  the  faces  of  the  stones  showing  on  the  inside  of  the 
walls  are  to  be  coarsely  bush-hammered. f)  The  wall  to  be  built 
plumb  and  carefully  levelled  on  top  to  receive  the  superstructure. 

Cementing  the  Outside  of  Walls. — As  soon  as  the  walls  are  com- 
pleted the  contractor  is  to  rake  out  all  loose  mortar  from  the  out- 
side joints  and  to  plaster  the  entire  outside  of  the  walls  (except 
wdiere  exposed  in  areas)  with  Portland  cement  mortar  not  less  than 
an  inch  thick.  The  mortar  and  sand  are  to  be  mixed  in  the  pro- 
portions of  I  to  I.  Area  walls  are  to  have  the  joints  raked  out 
and  pointed  with  cement  mortar,  and  false  joints  of  red  cement 
mortar  are  to  be  run  with  jointer  and  straight-edge.  The  trench 
is  not  to  be  refilled  until  the  wall  has  been  plastered  at  least  twenty- 
four  hours. 

Basement  Piers. — All  piers  colored  (blue)  on  the  basement  plans 

are  to  be  built  of   stone,  and  each  stone,  in  plan,  is  to  be  the 

full  size  of  the  cross-section  of  the  pier  in  which  it  is  usedlf  and 
laid  on  its  natural  bed ;  and  the  top  and  bottom  surfaces  of  each 
stone  are  to  be  cut  so  as  to  form  joints  not  exceeding  5^  an  inch 
in  width.  All  four  sides  of  the  piers  are  to  be  rough-pointed  and 
all  corners  pitched  off  to  a  line.  Each  top  stone  is  to  be  dressed 
to  receive  the  iron  plate  resting  on  each  pier  and  each  stone  is  to 
be  solidly  bedded  in  cement  mortar  as  specified  elsewhere. 

*  This  is  unnecessary  in  ordinary  foundations  dwellings. 

t  Required  only  in  places  where  a  neat  and  extra  strong  wall  is  required.  This  is 
expensive  work. 

t  Or  the  stones  may  be  laid  in  courses  varying  from  8  to  12  inches  in  height,  the 
stones  every  other  course  being  the  full  size  of  the  cross-section  of  the  pier  in  plan  and 
the  intermediate  courses  consisting  of  two  stones,  each  one-half  the  cross-section  of  the 
pier.    Each  stone  is  to  be  laid  on  its  natural  bed,  etc. 


CUT-STOKEWORK. 


821 


Mortar. — All  stone  masonry  referred  to  is  to  be  laid  in  mor- 
tar composed  of  perfectly  fresh  cement,  brand,  mixed 

in  the  proportion  of  i  part  of  cement  to  (2)  parts  of  clean,  sharp 
sand.  The  sand  and  cement  are  to  be  niixed  dry  in  a  box,  then 
wet,  tempered  and  immediately  used.  (See  Article  201.)  No 
mortar  that  has  commenced  to  set  is  to  be  used  on  the  work. 

686.  EXTERIOR   STONE  \N AU.S.— Rubble— The  exterior 

walls  (in  first  story)  are  to  be  built  of  rubble  stone  from  the  

quarries.  They  are  to  be  laid  random,  with  hammer-dressed  joints, 
and  the  outside  faces  are  to  be  so  split  that  no  projection 
exceeds  2  inches.  The  stones  are  to  be  laid  on  their  natural  bed, 
with  good  vertical  bond,  and  there  is  to  be  one  through  stone  to 
every  10  square  feet  of  wall.  All  stones  showing  on  the  exterior 
are  to  be  selected  from  the  largest  in  the  pile  and  as  few  spalls 
as  possible  to  be  used.  Every  stone  is  to  be  well  bedded  in  mortar, 
made  of  i  part  cement  and  (2)  parts  clean,  sharp  sand,  an^  all 
joints  and  chinks  are  to  be  filled  up  solid  with  mortar  and  spalls.  All 
inside  joints  are  to  be  smoothly  pointed  with  the  trowel  as  the  walls 
are  built.  After  the  walls  are  built  the  joints  on  the  outside  are  to 
be  raked  out  and  filled  wdth  cement  mortar,  and  false  joints  of 
Portland  cement  mortar  colored  red  are  to  be  run  with  jointer  and 
straight-edge,  in  imitation  of  broken-ashlar. 

Field  Rubble. — The  exterior  wall  of  the  (first  story)  is  to  be 
faced  with  round  field-stones,  selected  for  their  color,  and  any  moss 
or  lichens  is  to  be  left  on.  The  stones  are  to  be  fitted  together 
according  to  their  size  and  without  the  use  of  spalls.  The  back  and 
sides  are  to  be  split  with  a  hammer  when  necessary  to  make  a  bond, 
and  each  stone  is  to  have  its  long  axis  crosswise  of  the  wall  and 
is  to  be  laid  in  cement  mortar.  The  walls  are  to  be  backed  up 
with  split-faced  rubble  carefully  bonded  to  the  facing. 

CUT-STONEWORK. 

687.  GRANITE. — All  trimmings  colored  (blue)  on  the  elevation 

drawings  are  to  be  of   granite.    The  stock  is  to  be  carefully 

selected  and  to  be  free  from  all  natural  imperfections,  such  as 
mineral  stains,  sap  or  other  discolorations ;  and  it  is  to  be  of  an 
•even  shade  of  color  throughout,  so  that  one  stone  will  not  be  of  a 
dififerent  shade  from  another  when  set  in  place. 

The  faces  of  sills,  caps,  quoins  and  water-tables,  where  so  indi- 
cated on  the  elevation  drawings,  are  to  have  a  pitched-face  finish. 


822 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


with  i-inch  angle  margins  on  quoins  and  water-tables.  The  finish 
of  all  steps  and  thresholds  is  to  be  hammered  work,  six-cut,  and  the 
balance  of  the  finish  of  trimmings  is  to  be  the  best  eight-cut  w^ork. 

Sandstone. — All  trimmings  colored  (brown)  on  the  elevation 
drawings  are  to  be  of  best  quality  selected  sandstone,  of  uniform 
color  and  hardness,  free  from  sand  holes  and  rust,  and  cut  so 
as  to  lie  on  its  natural  bed  when  set  in  the  wall.  All  stone 
trimmings  thus  shown  are  to  be  worked  in  strict  accordance  with 
the  detail  drawings,  with  true  surfaces  and  good  sharp,  straight 
lines ;  and  all  stone  belts,  unless  otherwise  provided  for,  are  to  have 
a  bearing  upon  the  walls  of  at  least  (6)  inches,  and  all  projecting 
courses  a  bearing  of  2  inches  more  than  the  projection.  All 
exposed  surfaces  of  the  sandstone  are  to  be  carefully  tooled, 
(rubbed)  or  (crandalled) ,  the  workmanship  being  regular  and  uni- 
form m  every  part  and  done  in  a  skilful  manner.  All  moldings  are 
to  be  carefully  fitted  together  at  the  joints,  and  no  horizontal  or 
vertical  joint  is  to  exceed  1%  of  an  inch.  All  return  heads  at  the 
angles,  etc.,  are  to  be  at  least  (12)  inches  in  length.  No  patching 
of  any  stone  is  to  be  allowed. 

[Ordinary  soft  sandstones,  or  "freestones,"  are  not  suitable  for 
steps  and  door  sills,  which  should  be  of  granite  or  of  some  hard 
sandstone  or  limestone.] 

Ashlar. — The  (south)  and  (west)  walls  of  the  building  where 
exposxid  above  the  (water-table)  are  to  be  faced  with  coursed- 
(broken)  ashlar  of  the- same  stone  as  specified  for  the  trimmings. 
The  ashlar  is  to  be  laid  in  courses  (12)  inches  in  height,  except  as 
otherwise  shown  on  elevation  drawings,  and  is  to  have  plumb  bond 
wherever  practicable.  (The  surface  of  the  quoins  is  to  be  raised 
I  inch  from  the  face  of  the  wall,  with  bevelled  or  rusticated  joints, 
and  the  faces  of  the  stones  are  to  be  rusticated  in  a  skilful  manner. 
Each  quoin  is  to  be  (16)  by  (24)  inches,  alternately  reversed  as 
shown  on  the  drawings.)  The  balance  of  the  ashlar  is  to  be  rubbed 
to  a  true  surface,  to  be  out  of  wind,  cut  to  lie  upon  its  natural  bed, 
and  laid  up  with  -jVinch  joints.  No  stone  is  to  be  less  than  4 
inches  thick,  and  at  least  one  jamb  stone  of  each  opening  is  to 
extend  through  the  wall.  All  mullions  16  inches  or  less  in  width 
are  to  be  cut  the  full  thickness  of  the  wall 

The  contractors,  for  both  the  granite  and  the  sandstone,  are  to  do 
all  drilling,  lewising,  fitting  and  other  jobbing  required  for  setting 


CUT-STONEWORK. 


823 


the  stone  or  for  receiving  the  iron  ties,  clamps,  etc.,  and  are  to 
provide  all  patterns  necessary  and  requisite  for  the  execution  of 
the  work. 

Setting  Cut-stonework. —  [The  specifications  should  state  dis- 
tinctly who  is  to  set  the  cut-stonework.  If  it  consists  of  a  few 
trimmings  only  it  costs  less  to  have  the  brick-mason  set  it ;  but  if 
there  is  a  large  quantity  of  it,  it  should  be  set  by  the  stone-mason.] 

All  cut-stonework  colored  (blue)  or  (brown)  on  the  elevation 
drawings,  and  previously  specified,  is  to  be  set  by  this  contractor 
in  the  best  manner  in  mortar  mixed  in  the  proportions  of  2  parts 

of    lime  mortar  and  i  part  of  fresh    cement.  The 

cement  is  to  be  mixed  with  the  lime  mortar  in  small  quantities  and 
in  no  case  is  any  to  be  used  that  has  stood  over  night.  (For  setting 
limestone  and  marble  see  Article  311.) 

As  the  stone  is  delivered  at  the  building  the  mason  contractor  is 
to  receive  the  same  and  is  to  be  held  responsible  therefor  until  the 
full  completion  of  his  contract ;  any  damage  that  may  occur  to  any 
stone,  whether  on  the  ground  or  in  the  building,  during  the  said 
period,  is  to  be  made  good  at  his  own  expense  and  -to  the  satisfac- 
tion of  the  architect  or  superintendent. 

The  mason  is  to  call  upon  the  carpenter  to  box  up  or  otherwise 
protect  by  boards  all  steps,  moldings,  sills,  carving  and  any  other 
work  liable  to  be  injured  during  the  construction  of  the  building. 

Every  stone  is  to  be  carefully  set,  joints  are  to  be  left  open  under 
the  middle  part  of  sills  and  at  the  outer  edges  of  all  stonework.  All 
stones  are  to  be  uniformly  bedded  and  joints  kept  level  and  plumb 
and  of  uniform  thickness.  The  mason  is  to  provide  derricks  and 
all  other  apparatus  necessary  to  set  the  stone  properly  and  is  to 
carry  on  the  work  so  as  not  to  delay  the  other  mechanics.  Where 
the  stone  is  backed  up  with  brick  it  is  to  be  set  not  more  than  two 
courses  ahead  of  the  brick  backing. 

Anchors  and  Clamps. — This  contractor  is  to  provide  all  necessary 
iron  anchors  and  clamps  (which  are  to  be  galvanized  or  dipped 
in  tar)  for  securing  the  stones  as  herein  specified  or  as  directed 
by  the  superintendent. 

Each  piece  of  ashlar  12  inches  or  more  in  height  is  to  have  one 
iron  anchor  extending  through  the  wall,  and  when  exceeding  4 
feet  in  length  it  is  to  have  two  clamps.  (Broken  ashlar  is  to  be 
bonded  by  through  stones,  one  to  every  10  square  feet  of  wall.) 

i 


824 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


All  projecting  stones,  corbels,  finials,  etc.,  are  to  be  anchored  with 
iron  anchors  which  are  satisfactory  to  the  superintendent.  All 
coping  stones  and  other  horizontal  string-courses  or  cornices,  where 
so  indicated  by  notes  on  the  drawings,  are  to  be  clamped  together. 

Cleaning  and  Pointing. — After  all  the  stonework  is  set  complete 
(and  the  roof  is  on)  the  mason  is  to  scrub  it  down  with  muriatic 
acid  and  water,  using  a  stiff  bristle  brush ;  and  he  is  to  rake  out 
all  joints  to  a  depth  of  i  inch  and  repoint  them  with  Portland 

cement  and    red  mortar  color,  well  driven  into  the  joints 

and  rubbed  smooth  with  the  jointer  with  half-round  raised  joints, 
as  per  marginal  sketch.  (It  is  well  to  show  on  the  margin  of  the 
specifications  the  kind  of  joints  desired;  see  also  Article  313.) 

The  entire  work  is  to  be  left  clean  and  perfect  on  the  completion 
of  the  contract. 

SPECIFICATIONS  FOR  BRICKWORK. 

688.  This  contractor  is  to  furnish  all  materials,  including  water, 
and  all  labor,  scaffolding  and  utensils  necessary  to  complete  the 
brickwork  indicated  by  (red)  color  on  the  plans  and  sections  and 
as  shown  on  the  elevations  and  as  herein  specified. 

Pressed  Bricks. — The  exposed  surfaces  of  the  building  (on  the 
south  and  east  elevations),  including  the  chimneys,  are  to  be  faced 

with    pressed  bricks  like  the  sample  in  the  architect's  office. 

All  are  to  have  good  sharp  edges  and  to  be  of  uniform  size  and 
color. 

Molded  Bricks. — Furnish  all  molded  bricks  shown  on  elevation 

drawings  and  as  indicated  by  numbers  (which  refer  to   's 

catalogue).  The  color  of  these  bricks  is  to  match  as  closely  as 
possible  the  color  of  the  pressed  bricks,  which  are  to  be  laid  so 
as  to  give  to  all  moldings,  etc.,  lines  which  are  as  even  as  possible. 
Angle  bricks  are  to  be  furnished  for  external  angles  of  bays  and 
circular  bricks  of  proper  curvature  for  the  circular  bays  (or  towers). 

Stock  Bricks. — The  exposed  surfaces  of  the  brickwork  (on  the 
west  elevation)  are  to  be  laid  up  with  best  quality  dark  red  stock 
bricks,  with  good  sharp  corners  and  square  edges. 

Common  Bricks. — The  balance  of  the  exposed  brickwork  is  to 
be  constructed  of  selected,  even-colored  common  bricks  carefully 
culled  and  as  nearly  uniform  in  size  and  color,  as  can  be  obtained. 

All  face  bricks  are  to  be  laid  in  the  most  skilful  manner  (from 
outside    scaffolds)    in    colored    mortar,    as    specified  elsewhere. 


BRICKWORK. 


825 


Each  brick  is  to  be  dipped  in  water  before  it  is.  laid ;  the  bricks 
are  to  be  butted  and  all  vertical  joints  filled  solid  from  front  to 
back.  The  bricks  are  to  be  laid  with  plumb  bond  and  bonded  tO' 
the  backing  with  one  diagonal  header  to  every  brick  in  every  (fifth) 

course.    [Or  bonded  with  the    ties,  one  tie  being  laid  over 

every  brick  in  every  (fourth)  course.]  In  piers  only  solid  headers 
are  to  be  used. 

All  courses  are  to  be  gauged  true  and  all  joints  rodded  (or 
struck  with  a  bead  jointer.    See  Article  342). 

The  returns  of  pressed  brickwork  are  to  be  carefully  dovetailed 
into  the  common  brickwork  or  bonded  by  solid  headers. 

Ornamental  Work. — All  brick  cornices,  belt-courses,  arches, 
chimney  tops  and  other  ornamental  brick  features  of  the  building 
are  to  be  laid  up  in  the  most  artistic  and  substantial  manner, 
according  to  the  scale  and  detail  drawings.  All  arches  are  to  be 
bonded  and  the  bricks  cut  and  rubbed  so  that  each  joint  radiates 
from  the  center.  (Arch  bricks  are  often  specified  for  first-class 
work  in  large  cities.) 

Common  Brickzvork. — All  other  brickwork  is  to  be  laid  up  with 
good  hard-burned  (the  best  merchantable)  common  bricks,  accept- 
able to  the  architect,  and  in  mortar  as  specified  elsewhere. 

All  bricks  are  to  be  well  wet,  except  in  freezing  weather,  before 
being  laid. 

Each  brick  is  to  be  laid  with  a  shoved  joint  in  a  full  bed  of 
mortar,  all  interstices  being  thoroughly  filled,  and  where  a  brick  is 
laid  in  connection  with  anchors  it  is  in  every  case  to  be  "brought 
home"  to  do  all  the  work  possible. 

Up  to  and  including  the  fourth  story  every  fourth  course  is  to 
consist  of  a  heading  course  of  whole  bricks,  extending  through 
the  entire  thickness  of  the  wall  or  backing  ;  above  the  fourth  story 
every  sixth  course  is  to  be  a  heading  course. 

All  mortar  joints,  in  walls  which  are  not  to  be  plastered,  are  to 
be  neatly  struck,  in  the  manner  customary  in  first-class  trowel  work. 
All  courses  of  brickwork  are  to  be  kept  level  and  the  bonds 
accurately  preserved.  When  necessary  to  bring  any  courses  to 
the  required  height,  clipped  courses  are  to  be  formed  (or  the  bricks 
laid  on  edge),  as  in  no  case  are  any  mortar  joints  to  finish  more 
than  y2  an  inch  thick.    All  brickwork  is  to  be  laid  to  the  lines,  and 


826 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


all  walls  and  piers  built  plumb,  true  and  square.  Walls  are  to  be 
carefully  levelled  for  floor  joists. 

All  cut-stone  is  to  be  backed  up  as  fast  as  the  superintendent 
directs,  and  the  brick-mason  is  to  build  in  all  anchors  that  are 
furnished  by  the  contractor  for  the  cut-stonework,  by  the  contractor 
for  the  carpentry  work  or  by  the  contractor  for  the  ironwork. 

All  partition  walls  are  to  be  tied  to  the  outside  walls  by  iron 
anchors  (furnished  by  this  contractor),  f\j  by  inches  in  cross- 
section  and  (3  feet  6  inches)  in  length,  built  into  the  walls  every 
(4)  feet  in  height. 

When  openings  or  slots  are  indicated  in  the  brick  walls  the  size 
and  position  of  the  same  are  to  be  such  as  the  superintendent 
directs,  unless  otherwise  shown.  This  contractor  is  to  leave  open- 
ings to  receive  all  registers  that  may  be  required  in  connection  with 
the  heating  or  ventilating  system. 

The  work  is  to  be  firmly  bedded  and  filled  in  around  all  timbers, 
pointing  is  to  be  done  around  all  window  frames,  inside  all  staff- 
beads  and  window  sills  and  wherever  required,  and  all  wall-plates 
are  to  be  bedded  in  mortar  on  the  brickwork. 

Protection. — This  contractor  is  to  carefully  protect  his  work  by 
all  necessary  bracing  and  by  covering  up  all  walls  at  night  or  in 
bad  weather.  He  is  to  protect  all  mason  work  from  frosts  by 
covering  it  with  manure  or  other  materials  satisfactory  to  the 
superintendent. 

The  top  portions  of  all  walls  injured  by  the  weather  are  to  be 
taken  down  by  this  contractor  at  his  expense  before  recommencing 
the  work. 

Hollozv  Fire-clay  Bricks  (for  buildings  of  skeleton  construction). 
— All  bricks  used  in  connection  with  the  spandrels  above  the  first 
story  on  all  elevations,  together  with  all  backing  required  in  con- 
nection with  the  stone  or  terra-cotta  work  above  the  (sixth)  story 
floor  beams,  are  to  consist  of  first-quality  hard-burned  fire-clay, 
hollow  bricks,  equal  in  quality  to  the  sample  in  the  architect's  office. 
Each  brick  is  to  be  laid  with  a  shoved  joint  and  the  work  is  to  be 
well  bonded.  The  inside  surfaces  of  the  walls  are  to  be  left  smooth, 
true  and  ready  for  plastering. 

Cement  Mortar. — All  brickwork  below  the  grade  line  and  the  last 
five  courses  of  all  chimneys  and  parapet  walls  are  to  be  laid  in 
mortar  composed  of  i  part  fresh  cement  and  (2)  parts  clean,  sharp 


BRICKWORK. 


827 


bank  sand,  properly  screened,  and  mixed  with  sufficient  water  to 
give  the  mixture  proper  consistency.  Care  is  to  be  taken  to 
thoroughly  dry-mix  the  sand  and  cement  in  the  proportions 
specified  before  adding  the  water.  The  mortar  is  to  be  mixed  in 
small  quantities  only,  and  in  no  case  is  mortar  that  has  commenced 
tOv  set  or  that  has  stood  over  night  to  be  used.  (See  Articles  201 
to  205.) 

[In  Colorado,  and  possibly  in  some  other  localities,  a  gray 
hydraulic  lime  is  obtained,  which  answers  about  as  well  as  cement 
for  mortar  for  foundation  walls.] 

Lime-and-ccnient  Mortar. — xA.ll  common  brickwork  in  (first  and 
second)  stories  is  to  be  laid  in  mortar  composed  of  (3)  parts  of 
lime  mortar,  having  a  large  proportion  of  sand  and  of  i  part  of 

fresh    cement.    The  lime  mortar  is  to  be  worked  at  least 

two  days  before  the  cement  is  added,  and  only  small  quantities  of 
cement  are  to  be  mixed  at  a  time.   (See  Article  201.) 

Lime  Mortar. — The  balance  of  the  common  brickwork  is  to  be 

laid  in  mortar  composed  of  fresh-burned  lime  and  clean, 

sharp  sand,  well  screened.  (No  loam  is  to  be  used.)  The  lime 
and  sand  are  to  be  mixed  in  proportions  which  make  a  rich  mortar, 
satisfactory  to  the  architect.  Lime  that  has  commenced  to  slake  is 
not  to  be  used. 

Colored  Mortar. — All  face-bricks  are  to  be  laid  in  mortar  com- 
posed of  lime  putty  and  finely  sifted  sand,  colored  with  or 

  mortar  stains  ;  the  colors  are  to  be  selected  by  the  architect. 

Grouting. — All  brick  footings  and  the  piers  in  the  basement  are 
to  be  grouted  in  every  course  and  flushed  full  with  cement  mortar 
as  specified  above. 

Cement  Plastering. — The  outside  surfaces  of  all  brick  walls  that 
come  in  contact  with  the  earth  are  to  be  plastered  smooth  by  this 
contractor,  from  bottom  of  footings  to  grade  line,  with  Port- 
land cement  mortar,  mixed  in  the  proportion  of  I  to  2,  and  put  on  to 
an  average  thickness  of  }^  an  inch. 

The  top  surfaces  of  all  projecting  brick  belt-courses,  and  the  tops 
of  fire-walls,  where  not  otherwise  protected,  are  to  be  plastered  with 
the  same  kind  of  mortar,  care  being  taken  to  make  a  neat  job. 
(See  Article  346.) 

Relieving-arches. — Three  rowlock  relieving-arches  are  to  be 
turned  over  all  door  and  window  openings  behind  the  face-arch 


828  BUILDING  CONSTRUCTION.       (Ch.  XIII) 

or  lintel.  These  arches  are  to  have  brick  cores,  and  are  to  spring- 
from  beyond  the  ends  of  the  wood  lintels. 

Chimneys. — All  chimneys  and  vent-flues  are  to  be  built  as  shown 
on  plans,  sections  and  scale  drawings,  and  topped  out  as  shown  on 
elevation  drawings. 

All  withes  are  to  be  4  inches  thick  and  well  bonded  to  the  walls, 
and  the  flues  are  to  be  carried  up  separately  to  the  top.  The  inside 
of  all  flues  (unless  provided  with  flue  linings)  are  to  be  plastered 
from  bottom  to  top  with  (Portland  cement)  mortar,  and  the  out- 
side surfaces  are  to  be  plastered  where  the  flues  pass  through  floors. 
[The  plastering  of  the  inside  of  smoke  flues  is  not  allowed  in  some 
building  ordinances.] 

Slides  (slanting  boards)  are  to  be  put  in  each  flue  at  the  bottom, 
with  openings  above  to  take  out  the  mortar  droppings ;  and  on 
completion  of  the  chimneys  the  flues  are  to  be  thoroughly  cleaned 
out  and  the  openings  bricked  up. 

All  brick  chimney-breasts  are  to  be  built  plumb,  straight  and 
true,  and  all  corners  are  to  be  square. 

Rough  openings  are  to  be  built  for  fireplaces  (with  ^  by  2-inch 
iron  arch-bars,  turned  up  2  inches  at  the  ends)  and  trimmer  arches 
are  to  be  built  for  the  same,  2  feet  wide,  on  wooden  centers, 
furnished  and  set  by  the  carpenter. 

Ash-pits  are  to  be  built  Under  grates,  as  shown  on  plans,  and  a 
cast-iron  ash-pit  door  and  frame  are  to  be  provided  and  set  in  each 
pit  where  shown  or  directed. 

Flue  Linings. — Fire-clay  flue  linings,  8  by  12  inches  in  size,  are 
to  be  furnished  and  set  in  (the  range  flues  and  furnace  flues)  and 
are  to  start  (2  feet)  below  the  thimble  and  to  be  continued  to  the 
top  of  each  flue.  The  lining  is  to  be  set  in  rich  lime  (cement) 
mortar,  with  joints  scraped  clean  on  the  inside. 

Thimbles. — The  contractor  is  to  provide  and  place  in  all  flues, 
except  grate  flues,  (sheet)  iron  thimbles,  8  inches  in  diameter  in 
the  furnace  flue  and  6  inches  in  diameter  elsewhere,  and  set  2  feet 
below  the  ceiling  unless  otherwise  directed.  He  is  to  furnish 
bright-tin  stoppers  for  all  thimbles  except  for  (range  and  furnace). 

Cold-air  Duct. — Contractor  is  to  excavate  for  and  build  the 
cold-air  duct  and  foundation  for  furnace,  as  shown  on  drawings, 

of  hard-burned  bricks,  laid  in    cement  m.ortar,  and  plastered 

smooth  on  the  inside ;  he  is  also  to  plaster  the  bottom  of  duct  and 


BRICKWORK.  829 

furnace  pit  with  cement  mortar  on  a  2-inch  bed  of  sand.  The  top 
of  the  air  duct  is  to  be  covered  with  (23^) -inch  flagstones,  with 
joints  neatly  fitted  and  edges  cut  true  and  square.  The  flagging 
is  to  be  furnished  by  (this)  contractor. 

Fire-^ivalls. — This  contractor  is  to  furnish  and  set,  in  Portland 
cement,  salt-glazed  tile  copings  on  all  fire-walls  not  covered  by 
stone  or  metal  copings.  The  copings  are  to  be  2  inches  wider  thaa 
the  walls  and  are  to  have  lapped  joints. 

Ventilators. — Ventilating  openings  are  to  be  left  in  the  founda- 
tion walls  and  between  the  roof  and  ceiling  joists,  where  shown  on. 
drawings,  and  cast-iron  gratings  are  to  be  placed  in  the  openings. 

Cutting  and  Fitting. — This  contractor  is  to  do  promptly  and  at 
the  time  the  superintendent  directs  all  cutting  and  fitting  required 
in  connection  with  the  masonwork  by  other  contractors  in  order  that , 
their  w^ork  may  be  properly  installed,  and  he  is  to  "make  good" 
after  them. 

Setting  Ironwork. — This  contractor  is  to  set  all  iron  plates  rest- 
ing on  the  brickwork,  and  all  steel  beams  supporting  brick  walls  * 
also  all  iron  lintels,  tie-rods  and  skewbacks  used  in  connection  with 
brick  arches  or  over  openings. 

All  such  work  is  to  be  delivered  at  the  sidewalk  by  another  con- 
tractor, and  this  contractor  is  to  set  the  same  in  such  position  and 
at  such  height  as  the  superintendent  shall  direct.    All  plates  are  to 

be  solidly  bedded,  true  and  level,  in  i  to  2  fresh    Portland 

cement  mortar;  the  brickwork  is  to  be  brought  to  such  a  height 
that  the  bedding  joint  shall  not  exceed       an  inch  in  thickness. 

[Where  there  is  but  little  ironwork  it  is  sometimes  desirable  to 
specify  that  the  brick-mason  shall  assist  the  carpenter  in  setting 
iron  columns  and  steel  beams.  Large  contracts  for  iron  and  steel 
work  are  generally  carried  out  by  a  special  contractor.  All  iron- 
work coming  in  connection  with  the  stonework  should  be  set  by  the 
same  contractor  that  sets  the  stonework.] 

Setting  Cut-stone. — The  contractor  for  the  stonework  is  to  set 
all  belt-courses,  stone  arches,  copings,  steps  and  other  stones  where 
fitting  is  required ;  but  this  contractor  is  to  set  all  single  caps,  sills 
and  bond-stones,  the  stones  being  delivered  at  the  sidewalk.  All 
such  pieces  of  stone  are  to  be  set  in  the  best  manner,  in  mortar  as. 
specified  for  the  face-bricks.  Sills  are  to  be  bedded  at  the  ends 
only. 


830 


BUILDING  CONSTRUCTION.       (Ch.  XIII^ 


Set  finer  Tcrra-cotta. — This  contractor  is  to  set  all  terra-cotta 
work  colored  (pink)  on  the  elevation  drawings  in  the  best  manner 
and  in  the  same  kind  of  mortar  as  is  specified  for  the  pressed 
brickwork.  All  terra-cotta  work  that  does  not  balance  on  the  wall, 
and  any  other  terra-cotta  work,  if  so  indicated  on  the  drawings,  is 
to  be  securely  tied  to  the  backing  by  wrought-iron  anchors  of 
approved  pattern,  thoroughly  bedded  in  cement  mortar.  (See  also 
''Specifications  for  Terra-cotta  Work.") 

Cleaning  Dozvn  and  Pointing. — On  the  completion  of  the  brick- 
work this  contractor  is  to  thoroughly  clean  the  face-brick,  using 
dilute  muriatic  acid  and  water,  applied  with  a  scrubbing  brush.  Care 
is  to  be  taken  not  to  let  the  acid  run  over  the  cut-stone.  (Some 
stones  are  injured  by  acid  and  must  be  cleaned  with  water  only.) 
While  cleaning  down,  this  contractor  is  to  point  up  under  all  sills 
and  wherever  required,  in  order  to  leave  the  walls  in  perfect 
condition. 

[Where  there  is  little  cut-stonework  the  cleaning  and  pointing 
of  it  may  also  be  included  in  this  specification.] 

Outhouses.  [Generally  customary  only  in  Western  cities.] — The 
outhouses  and  ash-pit  are  to  be  built  of  hard-burned  bricks  on  the 
rear  of  the  lot  where  shown  on  plans.  The  ash-pit  is  to  be  arched 
over  and  given  a  heavy  coat  of  (Portland)  cement  mortar.  An 
opening  is  to  be  left  in  the  top  for  putting  in  ashes  and  an  iron 
ring  and  cover  provided  for  the  opening.  On  the  alley  side  at  the 
grade  a  cast-iron  ash-pit  door  and  frame  are  to  be  furnished  and  set. 

Rubbish. — This  contractor  is  to  clean  out  all  boards,  planks, 
mortar,  bricks  and  other  rubbish  caused  by  the  brick-masons,  and 
to  remove  such  rubbish  from  the  building  and  grounds,  on  com- 
pletion of  the  brickwork  or  when  directed  by  the  superintendent.* 

Brick  Paving  (for  yards). — The  yards  and  areas,  where  so  indi- 
cated on  plans,  a-re  to  be  paved  with  good  hard  (vitrified)  paving 
bricks,  sound  and  square,  laid  flat,  herringbone  fashion,  on  a  bed 
of  sand  from  (4)  to  (6)  inches  deep. 

[The  necessary  depth  of  sand  varies  with  the  quality  of  the  soil, 
a  stiff  clay  requiring  the  most  sand ;  on  such  soils  a  bed  of  furnace 
cinders,  etc.,  may  be  used  to  advantage  before  the  sand  is  put 
down.] 

After  the  bricks  are  laid  and  placed  with  the  proper  grade  (which 

*  If  in  the  general  conditions  this  paragraph  may  be  omitted  here. 


FIRE-PROOFING. 


831 


should  be  about  i  inch  in  10  feet),  to  drain  the  water  to  the  grade 
or  to  its  proper  outlet,  the  entire  surface  is  to  be  covered  with  sand, 
which  is  to  be  swept  over  the  bricks  until  the  joints  are  thoroughly 
filled. 

[For  a  better  pavement  the  joints  should  ^be  grouted  in  liquid 
cement  mortar  and  the  sand  spread  over  afterward.  Where  an 
extra  thickness  of  wearing  surface  is  required  the  bricks  may  be 
laid  on  edge  and  grouted  or  covered  with  sand  as  above.] 

Where  brick  gutters  are  shown  the  bricks  are  to  be  laid  length- 
wise and  the  joints  grouted  in  cement  mortar. 

(For  the  requirements  for  paving-bricks  for  streets  and  drive- 
ways see  Article  331.) 

SPECIFICATIONS  FOR  LAYING  MASONRY  IN 
FREEZING  WEATHER.* 

689.  Only  in  case  of  absolute  necessity  is  any  masonry  to  be  laict 
in  freezing  weather.    (See  Articles  213,  214  and  344.) 

Any  masonry  laid  in  freezing  weather  is  not  to  be  pointed  until 
the  warm  weather  in  the  spring.  If  necessary,  masonry  may  be  laid 
in  freezing  weather,  provided  the  stones  or  bricks  are  warmed 
sufficiently  to  remove  ice  from  the  surface  and  the  mortar  is  mixed 
with  brine  made  as  follows :  One  pound  of  salt  is  to  be  dissolved 
in  18  gallons  of  water  when  the  temperature  is  at  32°  Fahr.,  and 
I  ounce  of  salt  is  to  be  added  for  every  degree  the  temperature  is 
below  30°  Fahr.,  or  enough  salt,  whatever  the  temperature,  to 
prevent  the  mortar  from  freezing. 

SPECIFICATIONS  FOR  FIRE-PROOFING.ft 

(hollow  tile  system.) 

690.  The  following  specifications  are  intended  to  include  the 
fire-proofing  of  all  the  steel  in  the  building,  the  filling  in  between 
the  beams  forming  the  floors  and  the  roof  and  the  concreting,  over 
the  same  to  the  top  of  the  floor  strips.  They  include,  also,  the  cov- 
ering of  all  columns,  both  those  standing  clear  and  those  partly 
incased  in'the  walls,  the  building  of  all  tile  partitions  and  tile  vaults 
and  the  walls  of  pent-houses  on  the  roof. 

*  "Treatise  on  Masonry  Construction."     Ira  O.  Baker. 

t  Modelled  after  the  specification  for  the  l-'ort  Dearborn  building,  Chicago,  111.; 
Messrs.  Jenny  &  Mundie,  architects. 

X  On  account  of  various  changes  in  the  methods  and  details  of  this  branch  of* 
building  construction  this  form  for  the  specifications  for  fire-proofing  must  be  used  in 
the  light  of  the  revised  data  and  statements  given  in  Chapter  IX  on  "Fire-proofing  of 
Buildings." 


832 


BUILDIXG 


CONSTKUCTION. 


(Ch..  XIII) 


This  contractor  is  to  furnish  all  niateriais,  incluclmg"  the  mortar 
for  setting  the  same,  and  is  to  do  all  his  own  hoisting  axtd  set  all 
the  work  in  a  thorough,  substantial  and  workmanlike  manner,  to  the 
^satisfaction  of  the  superintendent. 

Mortar. — All  work  is  to  be  laid  in  mortar  composed  of  3'  parts 

of  best  fresh  lime  mortar  and  i  part  of   cement,  thoroughly 

mixed  together  just  before  using.  Said  lime  mortar  is  to  be  com- 
posed of  fresh-burned  lime  and  clean,  sharp  sand  in  proportions 
best  suited  to  this  work. 

Floors. — All  floors  are  to  be  constructed  of  flat  arches  (of  porous 
or  semi-porous  tiles,  end-method  construction"^)  set  in  between  the 
beams  and  of  a  shape  that  will  give  a  uniform  flat  ceiling  in)  the 
rooms  below.  The  bottoms  and  projections  of  all  beams-  and 
girders  are  to  be  protected  by  projecting  parts  of  the  tiles  or  by 
separate  beam  slabs.  In  laying  the  floor  arches  every  floor  joint  is 
to  be  filled  full  over  its  entire  surface  from  top  to  bottom.  No 
joints  are  to  exceed  -f^r  of  an  inch  in  thickness. 

No  clipped  or  broken  tiles  are  to  be  used  in  the  archeSy  and 
there  is  to  be  no  cutting  of  arches  except  where  absolutely  necessary 
or  with  the  approval  of  the  superintendent.  All  the  arches  are  to 
be  formed  to  fit  the  various  spans  between  floor  beams,  and  in  all 
cases  special  patterns  of  voussoirs  or  keys  are  to  be  molded  and  set 
where  it  is  impossible  to  set  the  regular  forms. 

All  floor  arches,  ten  days  after  they  are  laid,  and  before  they 
are  concreted,  are  to  be  subject  to  a  test  of  a  roller,  15  inches  face, 
and  loaded  so  as  to  weigh  1,500  pounds,  rolled  over  them  in  any 
direction. 

[This  test  is  only  intended  to  provide  against  poor  workmanship 
and  improper  setting  of  the  tiles.  If  any  system  whose  strength 
has  not  been  fully  demonstrated  is  to  be  used  it  should  be  sub- 
jected to  a  severer  test.] 

Columns. — All  columns  are  to  be  covered  with  (porous)  column 
tiles  held  by  metal  clamps,  both  in  the  horizontal  and  vertical  joints. 
These  column  protections  are  to  be  so  made  as  to  conform  with 
the  city  ordinances.    (See  Articles  416  and  417.) 

[Where  the  city  ordinances  are  not  sufficiently  strict  on  this 
point  the  specifications  should  be  more  definite  as  to  the  shape  of 
the  tiles.] 


*  This  clause  is  not  in  the  Fort  Dearborn  specification. 


FIRE-PROOFING.  833 

Roofs. — The  roofs  are  to  be  constructed  in  the  same  way  as  the 
floors,  except  that  the  tops  of  the  tiles  are  to  be  flush  with  the  beams 
and  that  the  soffits  may  be  segmental,  with  raised  skewbacks.  (See 
Article  463.) 

Partitions. — This  contractor  is  to  build  all  partitions  shown  on  the 
several  plans  of  (porous,  semi-porous  or  dense)  hollow  tiles,  4 
inches  thick  in  the  first  and  second  stories  and  3  inches  thick  in 
all  other  stories,  except  the  hall  partitions,  which  he  is  to  build 
4  inches  thick  throughout  the  building. 

In  glazed  partitions  the  lower  parts  and  all  parts  other  than  the 
sashes  and  frames  are  to  be  of  tile. 

The  tiles  are  to  be  set  breaking  joints  and  are  to  be  tied  with 
metal  ties  or  clamps.    (See  Articles  466  and  471.) 

Furring  for  False  Beams  and  Cornices. — This  contractor  is  also 
to  furnish  and  put  in  place  the  tile  furring  for  the  cornices  and  false 
beams  in  the  (bank  and  assembly-hall).  The  profiles  and  sections 
are  to  be  as  shown  on  the  drawings.    (See  Articles  484  and  487.) 

The  coves  and  ceiling  pieces  of  the  cornice  and  all  parts  of  the 
beams  are  to  have  holes  cast  for  bolts,  spaced  not  over  12  inches 
apart  and  for  at  least  two  bolts  for  each  piece.  The  furring  is 
to  be  properly  and  securely  mitered  at  angles  and  all  is  to  be  prop- 
erly bedded,  with  close  joints,  in  mortar  as  specified  above. 

All  suspended  pieces  are  to  be  substantially  fastened  in  place  with 
^-inch  diameter  T-head  boks,  spaced  not  over  12  inches  apart, 
with  nuts  and  washers  to  each. 

(Or,  all  furring  for  cornices  and  false  beams  are  to  be  put  up 
by  the  contractor  for  plastering.) 

Wall  Furring. — The  outside  walls  in  the  finished  portions  of  the 
basement  are  to  be  furred  with  3-inch  (porous,  semi-porous  or 
dense)  tiles,  so  as  to  form  vertical  and  true  surfaces  for  plastering  or 
tiling.  The  tiles  are  to  be  set  with  the  hollow  spaces  vertical,  and 
are  to  be  securely  fastened  to  the  walls  by  flat-headed  spikes.  (See 
Articles  484  and  485.) 

Miscellaneous.— AW  tilework  is  to  be  straight  and  true. 

All  tiles  of  every  kind  are  to  be  thoroughly  burned  and  free  from 
serious  cracks,  checks  or  other  damages,  and  are  to  be  laid  in  a. 
proper  and  workmanlike  manner. 

No  centers  are  to  be  lowered  until  the  mortar  has  set  hard. 


834 


BUILDING  CONSTRUCTION.       (Ch.  XIII> 


All  structural  steel  on  which  the  strength  of  the  building  depends, 
in  any  way,  including  the  wind-bracing,  is  to  be  protected  by  fire- 
proof covering  of  approved  shape  substantially  fixed  in  place. 

All  tilework  is  to  be  left  in  suitable  condition  for  plastering. 

Concreting. — This  contractor  is  to  fill  in  on  top  of  the  floor 

arches  with  concrete  composed  of  i  part  of    cement  mortar 

and  4  parts  of  screened  boiler  cinders,  levelled  ofif  at  the  top  of 
the  highest  beams  or  girders ;  and  after  the  floor  strips  are  set  by 
the  carpenter  the  contractor  is  to  fill  in  between  said  strips  with 
the  same  concrete  pressed  down  hard  with  a  reasonably  true  sur- 
face %  of  an  inch  below  the  top  of  the  strips. 

All  damage  to  tilework  is  to  be  repaired  before  the  concrete  is 
laid.    (See  Article  412.) 

Roofs. — This  contractor  is  to  cover  the  surface  of  the  roof  tiles 

with  I  to  3    cement  mortar  of  sufficient  thickness  to  come 

^  of  an  inch  above  the  top  flanges  of  beams  and  girders,  and  is 
to  give  the  required  pitch  to  the  roof,  with  a  reasonably  uniform 
surface.    (See  Articles  463  and  464.) 

[If  the  tops  of  the  tiles  are  more  than  ^  of  an  inch  below  the 
tops  of  the  girders,  concrete  may  be  used  for  filling  in  to  the  top 
of  the  girders  and  ^  inch  of  mortar  for  applying  above.] 

Pent-house. — The  outside  walls  of  the  pent-house  on  roof  are 
to  be  built  of  (4-inch)  hard-burned  wall  tiles,  clamped  together,  and 
set  in  mortar  as  above  specified.  Every  joint,  both  vertical  and 
horizontal,  is  to  be  thoroughly  filled  over  its  entire  surface  with 
mortar,  and  all  outside  joints  are  to  be  struck  in  a  neat  and  work- 
manlike manner. 

This  contractor  is  to  give  a  written  guarantee  that  the  outside 
face  of  these  tiles  will  stand  the  weather  for  (five)  years,  dating 
from  the  completion  of  the  walls,  and  is  to  agree  to  replace  any 
tiles  injured  by  the  weather,  either  in  winter  or  summer,  during 
said  period,  promptly  and  at  his  own  expense. 

SPECIFICATIONS  FOR  TERRA-COTTA  TRIM- 
MINGS.* 

691.  MATERIALS. — This  contractor  is  to  furnish  and  set, 
wherever  called  for  on  the  drawings,  terra-cotta  to  exactly  match  in 
color  the  sample  submitted,  all  in  strict  accordance  with  the  detail 


*  From  specifications  of  Fort  Dearborn  building. 


TERRA-COTTA  TRIMMINGS. 


835 


drawings.  Material  for  all  terra-cotta  is  to  be  carefully  selected 
clay,  left  in  perfect  condition  after  burning,  and  uniform  in  color. 
All  pieces  are  to  be  perfectly  straigbt  and  true,  and  with  mold  of 
tmiform  size  where  continuous.  No  warped  or  discolored  pieces  will 
be  allowed.  This  contractor  is  to  furnish  a  sufficient  number  of 
extra  pieces,  so  as  to  avoid  all  delay. 

Modelling. — All  work  is  to  be  carefully  modelled  by  skilled  work- 
men, in  strict  accordance  w4th  the  detail  drawings,  and  models  are 
to  be  submitted  for  the  architect's  approval  before  the  work  is 
burned.  No  work  burned  without  such  approval  will  be  accepted  by 
the  architects  unless  perfectly  satisfactory. 

Mortar. — All  mortar  used  for  exposed  joints  in  terra-cotta  work 

is  to  be  composed  of  lime  putty,  colored  with    mortar  stains 

to  match  the  mortar  used  for  pressed  brickwork. 

Ornamental  Fronts,  Belt-courses,  Bands. — This  contractor  is  to 
furnish  and  set  all  ornamental  terra-cotta,  belt-courses  and  bands, 
as  shown  on  elevations  or  sections  or  where  otherwise  indicated, 
in  strict  accordance  with  detail  drawings.  All  terra-cotta  work  is 
to  be  secured  to  the  ironwork  in  the  most  approved  manner,  with 
substantial  wrought-iron  or  copper  anchors,  and  thoroughly  bedded 
in  cement  mortar.  All  horizontal  joints  are  to  have  lap  joints.  AH 
projecting  courses  are  to  have  drips  formed  on  the  under  side. 

Caps,  Jambs  and  Sills. — i\ll  caps  and  jambs  where  indicated  as 
terra-cotta  are  to  be  constructed  in  strict  accordance  with  the  detail 
drawings.  All  sills  and  belt-courses  are  to  have  countersunk  cement 
joints  as  directed  by  the  superintendent.  All  projecting  sills  are  to 
have  drips  formed  on  the  under  side  and  all  sills  are  to  be  raggled 
for  hoop-iron,  which  is  to  be  bedded  by  this  contractor  in  cement 
mortar. 

Terra-cotta  Mnllions. — All  ornamental  mullions  of  terra-cotta 
are  to  be  secured  to  metal  uprights  in  an  approved  manner,  and 
are  to  be  well  bedded  and  slushed  with  cement  mortar. 

Cornices. — This  contractor  is  to  construct  the  cornices  in  strict 
accordance  with  the  detail  drawings,  with  sufficient  projection 
through  walls  and  approved  anchorage  to  the  metalwork  to  make 
them  thoroughly  secure.  This  contractor  is  to  furnish  all  necessary 
anchors.  He  is  to  form  raggle  in  cornices  as  shown  for  connection 
of  gutters ;  and  this  raggle  is  to  be  on  the  face  of  the  terra-cotta. 
He  is  to  leave  openings  in  the  cornices  for  down-spouts  as  shown. 


.836 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


Anchors. — This  contractor  is  to  furnish  all  anchors  substantially* 
made  of  wrought-iron  or  copper  for  the  proper  support  and  anchor- 
ins:  of  all  terra-cotta  used  in  his  work.  All  terra-cotta  is  to  be 
drawn  to  tight  and  accurate  joints  to  the  entire  satisfaction  of  the 
superintendent.  All  terra-cotta  is  to  fit  the  supporting  metalwork 
exactly. 

Cutting  and  Fitting. — This  contractor  is  to  do  all  fitting  necessary 
to  make  his  work  perfect  in  every  particular,  and  all  possible  cut- 
ting and  fitting  are  to  be  done  at  the  factory  before  delivery. 

Protection  of  Terra-cotta. — All  projecting  terra-cotta  is  to  be 
protected  with  sound  planks  during  the  erection  of  the  building 
by  the  terra-cotta  contractor,  and  said  protective  pieces  are  to  be 
removed  when  the  building  is  cleaned  down. 

Cleaning  Dozvn. — This  contractor  is  to  carefully  clean  down  all 
terra-cotta  work  on  the  completion  of  the  building,  when  directed 
by  the  superintendent,  and  he  is  to  carefully  point  up  all  joints 
before  leaving'  the  work. 

SPECIFICATIONS  FOR   LATHING  AND 
PLASTERING. 

(ordinary  work.) 
692.  LATHING. — All  (walls)  partitions  and  ceilings,  and  all 
furring,  studding,  under  sides  of  stairs,  etc.,  are  to  be  lathed  with 
best  quality  pine  (spruce)  laths,  free  from  sap,  bark  or  dead  knots, 
,  and  of  full  thickness.  They  are  to  be  laid  ^  of  an  inch  apart  on 
the  ceilings  and  ^  of  an  inch  or  more  apart  on  the  walls,  with 
four  (five)  nailings  to  a  lath  and  with  joints  broken  every  18 
inches ;  all  are  to  be  put  on  horizontally.  Under  no  circumstances 
are  laths  to  stop  and  form  long,  straight  vertical  joints,  nor  are 
any  laths  to  be  put  on  vertically  to  finish  out  to  angles  or  corners. 
No  laths  are  to  run  through  angles  and  behind  studding  from  one 
room  to  another.  All  corners  are  to  be  made  solid  before  lathing. 
Should  the  lathers  find  any  angles  which  have  not  been  made  solid, 
or  any  furring  or  studding  which  has  not  been  properly  secured, 
they  are  to  stop  and  notify  the  carpenter  to  make  the  same  solid 
and  secure. 

Metal  Lathing. — Walls  or  partitions  in  front  of  hot-air  pipes  are 
to  be  lathed  with  metal  lathing  approved  by  the  architect.  All 
recesses  in  brick  walls  that  are  to  be  plastered,  all  wood  lintels  and 
•all  places  where  woodwork  joins  brick  walls  (if  the  latter  are  not 


LATHING   AND  PLASTERING. 


837 


furred)  are  to  be  covered  with  .or  expanded-mctal  lathing 

properly  put  up  and  secured. 

PLASTERING.  Back-plastcring  (for  frame  buildings). — This 
contractor  is  to  back-plaster  the  entire  surface  of  the  exterior  walls 
between  the  studs  from  sills  to  plates,  and  also  between  the  rafters 
of  the  finished  portions  of  the  attic,  on  laths  nailed  horizontally,  ^ 
of  an  inch  apart,  to  other  laths  or  vertical  strips  put  on  the  inside 
of  the  boarding,  with  one  heavy  coat  of  lime-and-hair  mortar,  well 
trowelled  and  made  tight  against  the  studs,  girts,  plates  and  rafters. 

Onc-coat  Work. — The  (basement  ceiling)  is  to  be  plastered  one 
heavy  coat  of  rich  lime-and-hair  mortar,  well  trowelled  and 
smoothed. 

Tlircc-coat  Work. — All  other  walls,  partitions,  ceilings  and  soffits 
throughout  the  building  are  to  be  plastered  three  coats  in  the  best 
manner. 

The  first  or  scratch  coat  is  to  be  made  of  first  quality   

lump  lime,  clean,  sharp  bank  (river)  sand,  free  from  loam  and 
salt,  and  best  quality  clean,  long  cattle  hair,  mixed  in  the  proportion 
of  barrels  of  sand  and  bushels  of  hair  to  each  cask  or  each 
200  pounds  of  lump  lime.  All  are  to  be  thoroughly  mixed  by  con- 
tinued working  and  stacked  in  the  rough  for  at  least  (7)  days 
before  putting  on.  The  hair  and  sand  are  not  to  be  mixed  with 
the  lime  until  the  lime  has  been  slaked  at  least  six  hours. 

The  scratch  coat  is  to  be  properly  put  on  and  applied  with  suffi- 
cient force  to  give  a  good  clinch,  and  is  to  be  well  scratched  and 
allowed  to  dry  before  the  brown  coat  is  put  on. 

The  second  or  brown  coat  is  to  be  mixed  in  the  same  manner 
as  the  scratch  coat  (except  that  6^  barrels  of  sand  and  but  ^  a 
bushel  of  hair  to  i  of  lime  may  be  used);  The  contractor  is  to 
level  and  float  up  the  brown  coat  and  make  it  true  at  all  points. 

White  Coat. — The  third  coat  (except  in  the  halls  and  dining- 
room)  is  to  be  mixed  with  lime  putty,  plaster  of  Paris  and  marble 

dust   [or  lime  putty  and    hard  wall  plaster],  thoroughly 

trowelled  and  brushed  to  a  hard,  smooth  surface. 

Sand  Finish. — The  third  coat  in  the  halls  and  dining-room  is  to 
be  composed  of  lime  putty  and  clean-washed  (beach)  sand,  floated 
with  a  wooden  or  cork-faced  float  to  an  even  surface,  with  a  tex- 
ture corresponding  to  that  of  No.  i  sandpaper. 

All  lathing  and  plastering  are  to  extend  clear  down  to  the  floor; 


838 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


all  walls  are  to  be  straight  and  plumb  and  even  with  the  grounds ; 
and  all  angles  are  to  be  maintained  sharp  and  regular  in  form. 

Plaster  Cornices,  etc. — The  contractor  is  to  run  around  the 
(parlor)  a  plaster  stucco  cornice,  to  extend  (8)  inches  on  the  ceil- 
ings and  (6)  inches  on  the  walls,  and  to  be  in  strict  accordance 
with  the  detail  drawings.  All  beads,  quirks,  etc.,  are  to  be  run  to 
the  angles  of'  beam  soffits  as  indicated  on  the  drawings,  and  a 
finish  is  to  be  made  at  each  end  of  the  beams  with  cast  plaster 
brackets,  modelled  according  to  the  architect's  full-size  details. 

The  contractor  is  to  put  up  cast  plaster  centerpieces  in  (3)  rooms, 
for  which  he  is  to  allow  the  sum  of  ($25).  The  same  is  to  be 
expended  under  the  direction  of  the  architect. 

The  plasterer  is  to  clear  out  all  boards,  planks,  horses,  mortar, 
dirt  and  all  loose  rubbish  made  by  him  or  his  men,  and  remove 
such  materials  and  rubbish  from  the  rooms  and  premises  as  fast 
as  the  several  stories  are  plastered,  and  leave  the  floors  broom- 
clean.  He  is  to  patch  up  and  repair  the  plastering  after  the  car- 
penters and  other  mechanics  in  a  skilful  manner  and  leave  the  work 
perfect  on  completion. 

Tzuo-coat  Work.  Neztj  England  Practice. — The  following  is  the 
usual  form  of  specification  for  housework  in  New  England : 

All  walls,  ceilings,  soffits  and  partitions  throughout  the  (first  and 
second  stories  and  attic)  are  to  be  plastered  two  coats  in  the  very 
best  manner. 

''The  first  coat  is  to  be  of  best  quality  (Rockland)  lime  and  clean, 
sharp  sand,  well  mixed  with  1^/2  bushels  of  best  long  cattle  hair 
to  each  cask  of  lime ;  these  materials  are  to  be  thoroughly  worked 
and  stacked  at  least  one  week  before  using,  in  some  sheltered  place, 
but  not  in  the  cellar  of  the  house ;  all  the  work  is  to  be  well 
trowelled,  straightened  with  a  straight-edge,  made  perfectly  true 
and  brought  well  up  to  the  grounds. 

''The  second  or  'skim'  coat  is  to  be  of  best  (Rockland)  lime  putty 
and  washed  (beach)  sand,  trowelled  to  a  hard,  smooth  surface." 

SPECIFICATIONS  FOR  HARD  PLASTERING. 

693.  All  walls,  ceilings,  soffits  and  partitions  throughout  the 
building  are  to  be  plastered  three  coats,  in  the  best  manner,  as 
specified  on  opposite  page.  • 


IVIRE  LATHING 


839 


The  first  and  second  coats  are  to  be  of    wall  plaster  or 

dry  mortar  and  the  first  coat  on  the  lathvvork  is  to  be  fibered 
material. 

The  material  is  to  be  mixed  with  clean  water  to  the  proper  con- 
sistency and  applied  in  the  usual  way.  The  first  coat  is  to  be 
scratched  or  broomed  to  form  a  rough  surface  for  the  brown  coat. 
The  brown  coat  is  to  be  applied  as  soon  as  the  scratch  coat  is  two- 
thirds  dry  or  has  set  sufficiently  to  receive  it,  and  the  mortar  is  to 
be  brought  out  even  with  the  grounds  and  to  a  true  surface.  The 
work  is  to  be  scratched  roughly  for  all  stucco  cornices  and 
moldings. 

Sand  Finish. — After  the  brown  coat  has  been  on  twenty-four 
hours  the  plasterer  is  to  finish  the  walls  and  ceilings  of  (halls  and 

vestibules)  with    sand  finish,  mixed  with  clean  water  only 

and  floated  to  a  true  surface  with  clear  soft  pine  or  cork-faced 
floats. 

[Or  lime  putty  and  sand  may  be  used  as  in  ordinary  plastering.] 

Hard  Finish. — When  the  browning  is  two-thirds  dry  the  plasterer 
is  to  finish  all  other  walls  and  ceilings  throughout  the  building  with 
a  white  coat  made  of  equal  parts  of  lime  putty  and  plaster  of  Paris, 
trowelled  and  brushed  to  a  hard  and  uniform  surface. 

[For  a  better  grade  of  finish  a  quart  of  marble  dust  is  to  be 

added  to  each  batch  of  plaster,  or    hard  wall  finish  is  to 

be  used  instead  of  plaster  of  Paris.] 

All  brick  and  tile  walls  and  all  wooden  laths  are  to  be  well  wet 
just  before  plastering. 

Only  as  much  mortar  as  can  be  used  within  one  hour  is  to  be 
mixed  at  one  time,  and  under  no  circumstances  is  any  mortar  that 
has  commenced  to  set  to  be  retempered. 

The  plasterer  is  to  strictly  observe  and  follow  the  directions 
accompanying  the  plaster. 

[Specify  for  patching,  cornices,  etc.,  as  in  Article  692.] 

SPECIFICATIONS  FOR  WIRE  LATHING  WITH 
METAL  FURRING. 

(over  woodwork.) 

694.  This  contractor  is  to  fur  all  ceilings,  soffits  of  stairs,  all 
timber  beams  and  posts,  and  both  sides  of  all  wood  partitions 
throughout  the  building  with    metal  furring,  and  a  line 


840 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


of  furring  is  to  be  placed  on  each  side  of  each  angle,  as  near  the 
angle  as  possible.  Posts  and  girders  are  to  be  furred  lengthwise, 
with  a  line  on  each  angle,  and  every  (     )  inches  between. 

[If  the  architect  does  not  wish  to  specify  any  particular  or  patent 
kind  of  furring  he  can  specify  3/32  by  y^-'moh  corrugated  band- 
iron,  put  up  with  I ^ -inch  staples.] 

All  furring  is  to  be  substantially  secured  with  (  )  and  to 

be  set.  to  give  a  true  and  even  surface  for  the  lathing. 

This  contractor  is  to  cover  all  the  above  surfaces  with  (plain, 
painted,  japanned,  galvanized)  wire  lathing  (2^  by  2^)  (2^  by 
4)  mesh,  No.  (20)  wire,  tightly  stretched  and  secured  with  (2)- 
inch  No.  13  steel  staples  driven  over  the  lath  and  furring  at  each 
bearing  where  the  lathing  runs  crosswise  of  the  timbers,  and  every 
(6)  inches  where  the  bearings  run  parallel  with  the  timbers.  The 
lathing  is  to  be  lapped  at  least  ^  an  inch  where  the  strips  come 
together  and  or  2  inches  at  all  angles  of  walls  or  of  walls 
and  ceilings. 

SPECIFICATIONS  FOR  STIFFENED  WIRE 
LATHING. 

(over  woodwork  and  brickwork.) 

695.  This  contractor  is  to  cover  all  ceilings,  soffits  of  stairs,  both 
sides  of  all  wood  partitions,  and  all  wooden  posts  and  girders 

throughout  the  building   with  the    stiffened   wire  lath, 

painted,  No.  20  gauge,  and  (23/^  by  2^)  (2^  by  4)  mesh,  with 
(^-inch)  V-ribs.  [On  posts  and  girders  and  on  planking  i-inch 
ribs  will  give  better  protection  from  both  fire  and  dry  rot.] 

The  lathing  is  to  be  applied  with  the  ribs  running  at  right-angles, 
to  the  beams ;  it  is  to  be  tightly  stretched  and  secured  with  gal- 
vanized-steel  nails,  driven  through  each  end  of  each  rib,  and  at 
every  bearing  between ;  and  every  9  inches  on  timbers  and  plank- 
ing. The  strips  are  to  lap  on  a  joist  in  every  case  and  are  to  be 
carried  down  2  inches  on  the  walls.  Care  is  to  be  exercised  to  see 
that  no  holes  are  left  at  any  place  in  the  ceiling  where  the  plaster- 
ing can  drop  off  and  fire  enter. 

The  outside  walls  of  the  finished  portion  of  basement,  from  floor 

to  ceiling,  are  to  be  lathed  with    stiffened  lathing,  painted, 

No.  20  gauge,  (2>^  by  4)  mesh  and  i-inch  V-ribs.  The  lathing  is 
to  be  tightly  stretched,  lapped  i  inch  and  secured  to  the  walls  with 


METAL  LATH. 


841 


tenpenny  steel  nails  driven  through  the  ribs  everv  8 J/2  inches  and 
at  each  end.  The  lathing  is  to  be  applied  with  the  stiffening  bars 
in  a  vertical  position.  All  this  lathing  is  to  be  done  in  the  most 
approved  manner,  so  as  to  give  a  firm  surface  upon  which  to  apply 
the  plaster. 

SPECIFICATIONS  FOR  METAL  LATH  ON  IRON- 
WORK. 

696.  This  contractor  is  to  furnish  and  put  up  in  a  substantial 
manner  all  iron  furring  and  lathing  for  enclosing  the  posts  and 
girders  and  for  forming  the  cornices,  as  shown  on  the  drawings 
and  as  specified  below.  The  lathing  is  to  be  well  lapped  over  on. 
the  walls  and  ceilings  to  make  a  tight  job. 

Girders. — All  girders  projecting  below  the  level  of  ceilings  are 
to  be  encased  with  wire  lathing,  stiffened  with  ^-inch  solid  ribs. 
The  lathing  is  to  be  rightly  supported  by  light  iron  furring  built 
out  to  the  correct  outline  as  shown  on  the  plans.  The  furring  is 
to  be  so  designed  that  the  weight  of  the  plaster  and  falsework  will 
be  supported  by  the  girders  and  firm  surfaces  afforded  for 
plastering. 

Cornices. — Full-size  details  of  all  cornicework  is  to  be  supplied 
by  the  architects  at  the  proper  time.  Iron  brackets,  bent  to  correct 
outlines  and  spaced  not  more  than  18  inches  apart,  are  to  be  secured 
in  position  in  the  best  manner  and  well  braced.  Over  this  false- 
work, wire  lathing,  stiffened  with  y^-'moh  steel  ribs,  is  to  be 
laced  so  as  to  conform  with  the  profiles  of  the  brackets  and  produce 
smooth,  firm  surfaces  for  plastering. 

Columns. — All  columns  not  enclosed  in  brickwork  are  to  be  wire- 
lathed.  Suitable  light  iron  furring  is  to  be  provided  so  as  to 
offset  the  lathing:  at  least  2  inches  from  the  ironwork  and  finish 
round  or  square,  as  shown  on  the  plans.  The  lathing  is  to  be 
stiffened  with  ^-inch  solid  ribs  woven  in  every  y]^  inches. 

All  Other  Exposed  Iromvork. — This  is  to  be  suitably  encased  witli 
wire  lathing  supported  whenever  necessary  by  light  iron  furring, 
and  in  all  cases  providing  an  air-space  of  at  least  i  inch  between 
the  ironwork  and  the  plaster. 

All  of  the  above  lathing  is  to  be  painted  (galvanized),  of  No.  20 
gauge  and  (2^  by  4)  mesh  and  is  to  be  securely  laced  to  the 
furring  with  No.  19  galvanized  lacing  wire. 


842 


BUILDING  CONSTRUCTION.       (Ch.  XIII)" 


(All  work  here  contemplated  is  to  comply  with  the  requirements 
•of  the  Department  of  Building.) 

SOLID  PARTITIONS. 

(metal  lath  and  studding.) 

697.  This  contractor  is  to  provide  all  metalwork,  and  erect  the 
partitions  colored  (gray)  or  otherwise  marked  on  the  plans, 
and  leave  them  in  perfect  condition  for  the  plasterer.  Wood 
furring  will  be  furnished  in  pieces  of  the  proper  size  by  the  car- 
penter, but  this  contractor  is  to  secure  them  to  the  metalwork.  The 
above  partitions  are  to  be  formed  of  studs  of  y%  by  ^-inch  channel- 
iron,  placed  16  inches  on  centers  for  partitions  (11)  feet  or  less 
in  height  and  12  inches  on  centers  for  partitions  more  than  (11) 
feet  in  height.  All  openings  are  to  be  framed  with  i  by  i-inch 
by  iVinch  angle-irons. 

1.  The  studs  are  to  be  securely  fastened  at  top  and  bottom,  and 
the  grounds  for  door  and  window  openings  are  to  be  firmly  secured 
to  the  studs.  Grounds  for  the  nailing  of  base,  chair-rail,  picture- 
molds,  etc.,  are  to  be  fitted  and  fastened  in  place  and  made  true 
and  straight,  an  inch  over  the  line  of  studs  on  the  face  side  of 
the  partitions  and  34  of  an  inch  over  the  line  of  studs  on  the 
revefse  side,  the  total  thickness  being  i^/^  inches. 

2.  After  the  grounds  are  put  on,  the  face  side  of  each  partition 

is  to  be  covered  with  (   metal  lath)  ;  the  sheets  of  lath  are 

to  come  close  together  or  lap  on  the  horizontal  joints  and  the 
vertical  joints  are  to  be  broken  properly ;  the  lath  is  to  be  secured 
by  nailing  on  with  (trunk)  nails,  driven  through  alongside  of 
studs  and  clinched  around  behind  them,  each  nail  being  on  the 
opposite  side  of  a  stud  from  the  one  above  and  below  it.  The 
metalwork  is  to  be  properly  braced  to  hold  it  in  position  until  the 
mortar  has  become  firm. 

[The  bracing  should  be  straight-edged  flooring  boards  put  on 
over  the  lath.  Staples  set  around  the  studs  and  driven  into  the 
boards  can  be  easily  drawn  afterward,  leaving  only  i-inch  strips 
on  the  face  of  each  partition  and  the  staple  holes  on  the  reverse, 
to  be  filled  in  after  the  partitions  have  become  rigid.] 

[For  wire  lathing  the  specifications  are  to  be  as  follows,  instead 
of  as  in  paragraph  2  above.] 

3.  After  the  grounds  are  put  on,  one.  side  of  the  partitions  is 


CONCRETE  SYSTEM. 


843 


to  be  covered  with  No.  20  painted  (2>4  by  4) -mesh  wire  lathing, 
stiffened  with  ^-inch  solid  steel  ribs  woven  in  at  intervals  of 
7^  inches,  the  rods  running  crosswise  of  the  studs.  The  lathing 
is  to  be  firmly  secured  to  the  studding  with  No.  19  galvanized 
lacing  wire. 

SPECIFICATIONS   FOR   THE   ^'ROEBLING  CON- 
CRETE FLOOR  ARCH  SYSTEM." 

698.  [This  specification  is  given  as  a  guide  in  preparing  speci- 
fications for  this  and  similar  floors.  Most  of  the  various  fire- 
proofing  companies  have  printed  specifications  for  their  systems, 
which  they  furnish  to  architects  on  application.] 

The  floor  construction  to  be  used  in  this  building  is  to  be  that 
known  as  the  "Roebling  Concrete  Floor  Arch  System,"  consisting 
of  steel-ribbed  wire  cloth  centerings  and  cinder  concrete  arches 
with  ceilings  suspended  below  the  level  of  the  floor  beams.  Con- 
tinuous air-spaces  between  the  floors  and  ceilings  and  around  the 
girders  are  to  be  provided. 

The  wire  centering  for  the  floors  is  to  consist  of  No.  22  four- 
warp  two-filling  wire  cloth  stiffened  with  from  ^  to  ^-inch  steel 
rods  woven  into  the  cloth  at  intervals  of  about  9  inches.  This 
centering  is  to  be  sprung  in  between  each  pair  of  I-beams  in  the 
form  of  an  arch,  with  the  ends  of  the  rods  abutting  against  the 
beams.  The  sheets  are  to  be  well  lapped  and  securely  laced.  Over 
the  crown  of  this  centering  one  or  more  f\-inch  steel  rods  are  to 
be  laced  parallel  to  the  beams  to  secure  proper  longitudinal  bracing. 

In  all  spans  over  3  feet  6  inches,  at  intervals  of  not  over  3  feet, 
heavv  galvanized  wires  are  to  be  dropped  down  from  the  stiffening 
ribs  of  the  arch  to  support  the  ceiling. 

Over  the  wire  arch  so  constructed,  cinder  concrete,  mixed  in  the 
proportions  of  i  part  of  high-grade  Portland  cement  to  2^  parts 
of  sharp  sand  and  6  parts  of  clean  cinders,  is  to  be  laid,  providing 
a  thickness  of  not  less  than  (3)  inches  at  the  crown  of  the  arch. 
The  concrete  generally  is  to  be  levelled  up  to  a  height  of  (2  inches 
above)  the  tops  of  the  floor  beams  where  wood  floors  are  specified, 
and  to  the  specified  levels  where  other  than  wood  floors  are 
designated. 

Every  alternate  nailing-sleeper  is  to  be  imbedded  in  concrete  so 
as  to  form  a  fire-stop.    These  sleepers  are  to  be  supplied,  placed 


844 


BUILDING  CONSTRUCTION.       (Ch.  XIII)' 


in  position  over  the  beams  and  included  in  the  carpenter's  contract.. 

The  floors  are  to  be  subjected  to  tests  at  any  points  that  may 
be  designated  by  the  architect,  and  at  any  time  after  the  concrete 
is  fifteen  days  old.  The  floors  are  to  develop  in  all  cases  a  sup- 
porting strength  of  1,000  pounds  per  square  foot  when  the  load  is 
concentrated,  and  of  600  pounds  per  square  foot  when  the  load 
is  uniformly  distributed  over  one-half  of  the  span. 

SPECIFICATIONS  FOR  NATURAL  CEMENTS. 

[These  specificatiolis  are  given  as  guides  for  forms  and  methods 
of  procedure  in  preparing  specifications  for  this  part  of  masonry 
building  materials  and  construction.  (See  Article  168,  Chapter  IV, 
in  which  is  given  another  specification  for  natural  cements. 
The  specification  proposed  by  the  American  Society  for  Testing- 
Materials  is  not  given  here,  as  its  requirements  are  included  in 
the  form  given  in  Article  168.)  ] 

699.  SPECIFICATIONS  FOR  NATURAL  CEMENTS  FOR 
THE  NEW  YORK  STATE  CANALS,  i^g6.— Natural  Hydraulic 
Cement  is  to  be  of  the  best  quality  and  of  such  fineness  that  90 
per  cent  will  pass  through  a  sieve  of  2,500  meshes  per  square  inch 
and  80  per  cent  through  a  sieve  of  10,000  meshes  per  square  inch. 

Briquettes  made  of  equal  parts  of  natural  hydraulic  cement  and 
crushed  quartz,  immersed  in  water  as  soon  as  they  are  sufficiently 
hard  to  sustain  a  i/24-inch  wire  weighted  with  i  pound,  are  to 
show  a  tensile  strength  of  65  pounds  per  square  inch  at  the  expira- 
tion of  seven  days ;  but  briquettes  showing  less  than  such  strength 
are  to  be  held  until  twenty-eight  days  have  elapsed,  when,  if  they 
then  show  such  strength  as  to  sustain  as  many  pounds  per  square 
inch  above  125  as  the  seven-day  test  shows  them  to  have  fallen 
below  65,  they  are  to  be  deemed  to  have  passed  this  test.  Briquettes 
made  of  neat  cement  are  not  to  set  so  as  to  support  a  1/ 12-inch 
wire  with  a  load  of  34  of  ^  pound  in  less  than  five  minutes. 
Briquettes  of  neat  cement  are  not  to  show  checks  or  cracks  when 
immersed  in  water  for  seven  days  after  mixing. 

700.  SPECIFICATIONS  FOR  NATURAL  CEMENT  FOR 
THE  RAPID  TRANSIT  SUBWAY,  NEW  YORK  CITY,  1900- 
1901. — Fineness. — Ninety-five  per  cent  is  to  pass  a  No.  50  sieve 
and  85  per  cent  at  No.  100  sieve. 

Tensile  Strength. — At  the  end  of  seven  days,  one  day  in  air,  six 


NATURAL  CEMENTS.  845 

days  in  water,  125  pounds,  neat.  At  the  end  of  twenty-eight  days, 
one  day  in  air,  twenty-seven  days  in  water,  200  pounds,  neat.  When 
mixed  i  to  i  with  quartz  sand :  at  end  of  seven  days,  one  day  in 
air,  six  days  in  water,  100  pounds  ;  at  the  end  of  twenty-eight  days, 
one  day  in  air,  twenty-seven  days  in  water,  150  pounds. 

Soundness. — Tests  for  checking,  cracking  and  color  are  to  be 
made  by  mokhng,  on  plates  of  glass,  cakes  of  neat  cement  about 
3  inches  in  diameter,  ^  an  inch  thick  in  the  center,  and  very  thin 
at  the  edges.  One  of  these  cakes,  when  it  is  set  perfectly  hard,  is 
to  be  put  in  water  and  examined  for  distortion  and  cracks  ;  and  one 
is  to  be  kept  in  air  and  examined  for  color,  distortion  and  cracks. 

701.  SPECIFICATIONS  FOR  NATURAL  CEMENT.  EN- 
GINEER CORPS,  U.  S.  ARMY,  1901.— (i)  The  cement  is  to  be 
a  freshly  packed  natural  (or  Rosendale),  dry  and  free  from  lumps. 
By  natural  cement  is  meant  one  made  by  calcining  natural  rock 
at  a  heat  below  incipient  fusion  and  grinding  the  product  to  powder. 

(2)  The  cement  is  to  be  put  up  in  strong,  sound  barrels,  well 
lined  with  paper  so  as  to  be  reasonably  protected  against  moisture,, 
or  in  stout  cloth  or  canvas  sacks.  Each  package  is  to  be  plainly 
labelled  with  the  name  of  the  brand  anfl  of  the  manufacturer.  Any 
package  broken  or  containing  damaged  cement  may  be  rejected,  or 
accepted  as  a  fractional  package,  at  the  option  of  the  United  States 
agent  in  local  charge. 

(3)  Bidders  are  to  state  the  brand  of  the  cement  which  they 
propose  to  furnish.  The  right  is  reserved  to  reject  a  tender  for 
any  brand  which  has  not  given  satisfaction  in  use  under  climatic 
or  other  conditions  of  exposure  of  at  least  equal  severity  to  those 
of  the  work  proposed. 

(4)  Tenders  are  to  be  received  from  manufacturers  or  their 
authorized  agents  only. 

The  following  paragraph  is  to  be  substituted  for  paragraphs 
(3)  and  (4)  above  when  cement  is  to  be  furnished  and  placed  by 
the  contractor : 

(No  cement,  except  established  brands  of  high-grade  natural 
cement  which  have  been  in  successful  use  under  climatic  conditions 
similar  to  those  of  the  proposed  work,  is  to  be  used.) 

(5)  The  average  net  weight  per  barrel  is  to  be  not  less  than 
300  pounds.  (West  of  the  Allegheny  Mountains  this  mav  be  265 
pounds.)     Sacks  of  cement  are  to  have  the  same  weight  as  i 


846 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


barrel.  If  the  average  net  weight,  as  determined  by  test  weigh- 
ings, is  found  to  be  below  300  pounds  (265  pounds)  per  barrel,  the 
cement  may  be  rejected,  or,  at  the  option  of  the  engineer  officer  in 
charge^  the  contractor  may  be  required  to  supply  free  of  cost  to 
the  United  States  an  additional  amount  of  cement  equal  to  the 
shortage. 

(6)  Tests  may  be  made  of  the  fineness,  time  of  setting  and  ten- 
sile strength  of  the  cement. 

(7)  Fineness. — At  least  80  per  cent  of  the  cement  is  to  pass 
through  a  sieve  made  of  No.  40  wire,  Stubbs'  gauge,  having  10,000 
openings  per  square  inch. 

(8)  Time  of  Setting. — The  cement  is  not  to  acquire  its  initial 
set  in  less  than  twenty  minutes  and  must  have  acquired  its  final 
set  in  four  hours. 

(9)  The  time  of  setting  is  to  be  determined  from  a  pat  of  neat 
•cement  mixed  for  five  minutes  with  30  per  cent  of  water  by  weight 
;and  kept  under  a  wet  cloth  until  finally  set.  The  cement  is  con- 
.'sidered  to  have  acquired  its  initial  set  when  the  pat  will  bear,  with- 
'out  being  appreciably  indented,  a  wire  1/12  of  an  inch  in  diameter 
loaded  with  a  54"po^^ii<^l  weight.  The  final  set  is  considered  to  have 
been  acquired  when  the  pat  will  bear,  without  being  appreciably 
indented,  a  wire  1/24  of  an  inch  in  diameter  loaded  with  a  r-pound 
•weight. 

(10)  Tensile  Strength. — Briquettes  made  of  neat  cement  are 
to  develop  the  following  tensile  strengths  per  square  inch,  after 
having  been  kept  in  air  for  twenty-four  hours  under  a  wet  cloth 
and  the  balance  of  the  time  in  water: 

At  the  end  of  seven  days,  90  pounds ;  at  the  end  of  twenty-eight 
days,  200  pounds. 

Briquettes  made  of  one  part  of  cement  and  one  part  of  standard 
sand  by  weight  are  to  develop  the  following  tensile  strengths  per 
square  inch : 

After  seven  days,  60  pounds;  after  twenty-eight  days,  150 
pounds. 

(11)  The  highest  result  from  each^  set  of  briquettes  made  at 
any  one  time  is  to  be  considered  the  governing  test.  Any  cement 
not  showing  an  increase  of  strength  in  the  twenty-eight-day  tests 
over  the  seven-day  tests  is  to  be  rejected. 

(12)  The  neat  cement  for  briquettes  is  to  be  mixed  with  30  per 


NATURAL  CEMENTS. 


847 


cent  of  water  by  weight,  and  the  sand  and  cement  with  17  per  cent 
of  water  by  weight.  After  being  thoroughly  mixed  and  worked  for 
five  minutes  the  cement  or  mortar  is  to  be  placed  in  the  briquette 
mold  in  four  equal  layers,  each  of  which  is  to  be  rammed  and  com- 
pressed by  thirty  blows  of  a  soft  brass  or  copper  rammer  ^  of 
an  inch  in  diameter  (or  7/10  of  an  inch  square  with  rounded  cor- 
ners), weighing  i  pound.  It  is  to  be  allowed  to  drop  on  the  mix- 
ture from  a  height  of  about  ^  an  inch.  Upon  the  completion  of 
the  ramming  the  surplus  cement  is  to  be  struck  off  and  the  last 
layer  smoothed  with  a  trowel  held  in  a  nearly  horizontal  position 
and  drawn  back  with  sufficient  pressure  to  make  its  edge  follow 
the  surface  of  the  mold. 

(13)  The  above  are  to  be  considered  the  minimum  require- 
ments. Unless  a  cement  has  been  recently  used  on  work  under 
the  direction  of  this  office,  bidders  are  to  deliver  a  sample  barrel 
for  tests  before  the  opening  of  the  bids.  Any  cement  showing  by 
sample  higher  tests  than  those  given  are  to  maintain  the  average 
so  shown  in  subsequent  deliveries. 

(14)  A  cement  which  fails  to  meet  any  of  the  above  require- 
ments may  be  rejected.  An  agent  of  the  contractor  may  be  present 
at  the  making  of  the  tests,  or,  in  case  of  the  failure  of  any  of 
them,  they  may  be  repeated  in  his  presence.  If  the  contractor  so 
desires,  the  engineer  officer  may,  if  he  deems  it  to  the  interest  of 
the  United  States,  have  any  or  all  of  the  tests  made'  or  repeated  at 
some  recognized  standard  testing  laboratory  in  the  manner  above 
specified.  All  expenses  of  such  tests  are  to  be  paid  by  the  contrac- 
tor, and  all  such  tests  are  to  be  made  on  samples  furnished  by  the 
engineer  officer  from  cement  actually  delivered  to  him. 

SPECIFICATIONS  FOR  PORTLAND  CEMENTS. 

[These  specifications  and  extracts  from  the  same  are  given  as 
guides  for  forms  and  methods  of  procedure  in  preparing  specifica- 
tions for  this  part  of  the  masonwork.  There  are  now  published  so 
many  specifications  for  work  actually  carried  out  that  the  engineer, 
architect  or  contractor  will  have  no  difficulty  in  finding  numerous 
forms  for  use  in  comparison  and  for  adaptation  to  any  particular 
construction.  (See  Article  180,  Chapter  IV,  in  which  is  given  an 
excellent  specification  for  Portland  cements.  The  specification  pro- 
posed by  the  American  Society  for  Testing  Materials  is  not  given 


■848 


BUILDING  CONSTRUCTION, 


(Cii.  XIII) 


here,  as  its  requirements  are  included  in  the  form  given  in  Article 
180.)  ] 

702.  EXTRACT  FROM  SPECIFICATIONS  FOR  PORT- 
LAND CEMENT  FOR  THE  NEW  YORK  STATE  CANALS, 
igg5.. — Portland  Cement  is  to  be  of  the  best  quality  and  of  such 
fineness  that  95  per  cent  of  the  cement  will  pass  through  a  sieve  of 
2,500  meshes  to  the  square  inch,  and  90  per  cent  through  a  sieve  of 
10.000  meshes  to  the  square  inch.  Portland  cement  when  mixed 
neat  and  exposed  one  day  in  air  and  six  days  in  water  is  to  with- 
stand a  tensile  stress  of  not  less  than  400  pounds  to  the  square  inch, 
and  when  mixed  in  the  ratio  of  3  pounds  of  clean,  sharp  sand  to  i 
pound  of  cement  and  exposed  one  day  in  air  and  six  days  in  water, 
it  is  to  withstand  a  tensile  stress  of  not  less  than  125  pounds  per 
square  inch. 

703.  SPECIFICATIONS  FOR  PORTLAND  CE^IENT  FOR 
THE  RAPID-TRANSIT  SUBWAY,  NEW  YORK  CITY,  1900- 
igoi. — Fineness. — Ninety-eight  per  cent  is  to  pass  a  No.  50  sieve 
and  90  per  cent  a  No.  100  sieve. 

Tensile  Strength. — When  neat:  At  the  end  of  one  day  in  water 
after  hard  set,  150  pounds;  at  the  end  of  seven  days,  one  day  in 
air,  six  days  in  water,  400  pounds ;  at  the  end  of  twenty-eight 
days,  one  day  in  air,  twenty-seven  days  in  water,  500  pounds. 
When  mixed  2  to  i  with  quartz  sand :  At  the  end  of  seven  days, 
one  day  in  air,  six  days  in  water,  200  pounds ;  at  the  end  of  twenty- 
eight  days,  one  day  in  air,  twenty-seven  days  in  water,  300  pounds. 

Chemical  Analysis. — Chemical  analysis  is  to  be  made  from  time 
to  time  and  cement  furnished  is  to  show  a  reasonably  uniform 
composition. 

Soundness. — Tests  for  checking  and  cracking  and  for  color  are 
to  be  made  by  molding,  on  plates  of  glass,  cakes  of  neat  cement 
about  3  inches  in  diameter,  ^  an  inch  thick  in  the  center  and 
very  thin  at  the  edges.  ■  One  of  these  cakes  when  set  perfectly  hard 
is  to  be  put  in  water  and  examined  for  distortion  and  cracks ;  and 
one  is  to  be  kept  in  air  and  examined  for  color,  distortion  and 
•cracks.  Another  cake  is  to  be  allowed  to  set  in  steam  for  twenty- 
four  hours  and  is  then  to  be  put  in  boiling  water  for  twenty-four 
hours.  Another  cake  is  to  be  allowed  to  set  hard  in  dry  air  for 
twenty-four  hours  and  is  then  to  be  put  in  boiling  water  for  twenty- 
four  hours.  Such  cakes  should  at  the  end  of  the  tests  still  adhere 
to  the  glass  and  show  neither  cracks  nor  distortion.    A  briquette. 


REIX FORCED  COX CRETE 


849 


in  like  manner,  should  be  allowed  to  set  hard  in  dr  .-  air  for  twenty- 
four  hours,  should  then  be  boiled  for  twenty-four  hours,  kept  for 
five  days  in  water  and  show  350  pounds  tensile  strength. 

SPECIFICATIONS  FOR  REINFORCED  CONCRETE 

WORK.* 

704.  PORTLAND  CRUE^T— Shipments.— AW  shipments  are 
to  consist  of  well-seasoned  cement,  to  meet  the  following  specifica- 
tion : 

Storage. — After  delivery,  all  cement  is  to  be  stored  in  a  suitable 
and  convenient  building  to  permit  of  easy  access  for  proper  inspec- 
tion and  identification  of  each  shipment.  At  least  twelve  days'  time 
is  to  be  allowed  for  inspection  and  necessary  tests  before  using. 

Testing. — All  cement  is  to  be  inspected  either  at  the  time  of 
shipment  or  upon  delivery,  and  is  required  to  meet  the  tests  • 
herein  prescribed  before  being  used  in  the  work.  Where  prac- 
ticable, samples  for  testing  may  be  taken  from  cars  before  leaving 
the  cement  works,  the  tests  being  made  while  the  cement  is  in 
transit.    The  cost  of  said  testing  is  to  be  borne  by  the  owner. 

Quality. — The  cement  is  to  equal  in  quality  the  best  grade  of 
American  Portland  cement ;  blending  will  not  be  tolerated. 

Specific  Gravity. — The  cement  is  to  have  a  specific  gravity  of  H 
not  less  than  3.10. 

Fineness. — Not  more  than  8  per  cent  is  to  be  retained  upon  a 
No.  100  sieve,  nor  more  than  25  per  cent  upon  a  No.  200  sieve. 
-  Set. — The  cement  is  not  to  develop  initial  set  in  less  than  30 
minutes,  and  must  have  acquired  its  hard  set  in  less  than  8  hours. 

Soundness ;  Accelerated  Test. — Pats  of  neat  cement  are  to  be 
allowed  to  harden  24  hours  in  moist  air,  and  are  then  to  be  sub- 
jected to  the  accelerated  test  as  follows: 

A  pat  is  to  be  exposed  in  any  convenient  way  in  an  atmosphere 
of  steam,  above  boiling  water,  in  a  loosely  closed  vessel  for  2 
hours,  after  which,  before  the  pat  cools,  it  is  to  be  placed  in  the 
boiling  water  for  5  additional  hours. 

To  pass  the  accelerated  test  satisfactorily,  the  pats  are  to  remain 
firm  and  hard  and  show  no  signs  of  cracking,  distortion  or  disin- 
tegration. 

*  Taken  and  adapted  from  the  specifications  for  the  Edward  Stern  &  Company's 
printing  house,  Philadelphia,  Pa.,  erected  in  igoS,  Messrs.  Ballinger  &  Perrot,  architects 
and  engineers,  Philadelphia,  Pa.  These  specifications  are  reproduced  by  permission  and 
through  the  courtesy  of  the  architects. 


850 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


^Og. — The  cement  is  not  to  contain  more  than  1.75  per  cent  of 
anhydrous  sulphuric  acid. 

Tensile  Strength. — Tensile  tests  are  to  be  made  on  specimens 
prepared  and  maintained  until  tested  at  a  temperature  as  near  as 
practicable  to  70  degrees  Fahrenheit.  Each  specimen  is  to  have 
an  area  of  one  square  inch  at  the  breaking  section,  and  after  being 
allowed  to  harden  in  moist  air  for  24  hours  is  to  be  immersed  and 
maintained  in  water  until  tested.  The  sand  used  in  preparing  test- 
specimens  is  to  be  clean,  sharp,  crushed  quartz,  retained  on  a 
sieve  of  30  meshes  per  lineal  inch  and  passing  through  a  sieve  of 
20  meshes  per  lineal  inch. 

The  minimum  tensile  strength  in  pounds  per  square  inch  from 
test  specimens  is  to  be  as  follows : 

NEAT  CEMENT. 

24  hours  (in  moist  air)  150  lbs. 

7  days  (i  day  in  moist  air,    6  days  in  water)    500  lbs. 
28  days  (i  day  in  moist  air,  27  days  in  water)    600  lbs. 

I  PART  CEMENT,  3  PARTS  SAND. 

7  days  (i  day  in  moist  air,    6  days  in  water)    200  lbs. 
28  days  (i  day  in  moist  air,  27  days  in  water)    280  lbs. 

The  average  of  sand-test  specimens  should  develop  a  tensile 
strength  from  10  to  40  per  cent  greater  than  the  above  minimums. 

The  rules  recommended  by  the  committee  of  the  American 
Society  of  Civil  Engineers  on  uniform  tests  of  cement,  as  pub- 
lished in  the  proceedings  of  the  said  society  for  the  month  of  Janu- 
ary, 1903,  are  to  be  followed  in  making  the  above  tests. 

705.  REINFORCED  CONCRETE  WORK.— T/z^^  Construc- 
tion in  General. — Two  methods  of  reinforced  concrete  construction 
are  shown  on  the  drawings.  One  is  the  ''beam  and  girder  con- 
struction" and  the  other  is  the  ''trough  system  of  construction." 
Either  system  may  be  used,  but  the  contractor  is  to  state  in  his 
bid  which  system  he  proposes  to  adopt. 

The  contractor  is  to  build  the  reinforced  concrete  work  complete, 
as  shown  and  required  by  the  drawings,  and  in  accordance  with 
the  regulations  of  the  Philadelphia  Bureau  of  Building  Inspection. 

The  contractor  is  to  furnish  all  labor  and  materials  for  the 
construction  of  the  reinforced  concrete  work.  He  is  to  build  all 
concrete  work  of  whatsoever  nature,  excepting  such  footings  as  are 


REINFORCED  CONCRETE. 


necessary  for  the  underpinning  of  adjacent  walls,  as  mentioned 
under  the  heading  ''Excavation,  Foundation  Masonry  and  Under- 
pinning." All  footings  for  walls,  columns  and  partitions  are  to  be 
included.  The  contractor  is  also  to  construct  all  area  and  other 
walls  and  all  stairs  of  reinforced  concrete  where  required  by  the 
drawings. 

.Falsework,  Forms,  Centering  and  Shores. — The  contractor  is  to 
perform  all  labor  and  furnish  all  material  for  the  construction  of  all 
forms  and  woodwork  necessary  to  complete  the  concrete  work.  The 
beam,  girder  and  column  forms  are  to  have  sides  at  least  i)4  inches 
thick,  and  the  centering  for  the  slabs  is  to  consist  of  i-inch  material, 
tongued  and  grooved  and  battened  together  into  panels.  The  forms 
are  to  be  so  constructed  that  they  can  be  taken  down  without  dam- 
aging the  concrete  or  spalling  the  corners. 

All  forms  are  to  be  made  true  to  line  and  are  to  be  plumb  and 
level. 

The  contractor  is  to  provide  bevelled  strips  in  the  bottom  of  all 
beam  and  girder  forms  and  level  the  centering  to  form  ceiling 
angles. 

The  method  of  centering  is  to  permit  of  the  earlier  removal  of 
the  slab  forms  and  sides  of  beams  and  the  leaving  in  position  of 
the  shores  and  bottom  forms  of  beams  and  girders.  The  latter  are 
to  remain  in  position  at  least  two  weeks  in  the  most  favorable 
weather,  and  as  much  longer  as  may  be  necessary. 

The  centering  for  the  trough  construction  is  to  be  made  in  any 
approved  substantial  manner  and  of  such  material  and  construc- 
tion as  will  result  in  good  work  at  the  completion  as  well  as  at 
the  commencement  of  the  work. 

A  sufficient  number  of  sets  of  centers  or  forms  are  to  be  used, 
as  set  forth  in  the  "General  Conditions,"  to  carry  on  the  work 
without  delay  or  interruption. 

A  sufficient  number  of  shores  for  the  proper  support  of  the  forms, 
the  dead  weight  of  the  wet  concrete  and  the  loads  incidental  to 
placing,  are  to  be  provided,  and  are  to  rest  on  solid  foundations 
and  remain  in  position  until  the  concrete  is  sufficiently  strong  to 
support  the  weight  of  any  upper  floors  which  may  depend  upon 
such  shores. 

Care  is  to  be  exercised  to  see  that  the  soil  is  suitable  for  the 
support  of  the  bottom  struts,  and  doe'^  not  compress  under  the 


852 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


load.    If  the  latter  condition  prevails,  trussed  supports  are  to  be 
provided  for  the  forms. 

Forms   are   to   be   sufficiently   rigid   to   avoid   any  deflection 
whatever. 

All  the  forms  of  the  entire  work  are  to  be  made  with  smooth 
dressed  material,  accurately  put  together  and  neatly  fitted.  No 
warped  or  twisted  boards  are  to  be  used  in  the  construction  of  the 
face  of  the  molds,  and  all  the  molds  are  to  be  thoroughly  swept 
and  cleaned  before  the  concrete  is  laid. 

Any  necessary  form  work  is  to  be  provided  also  for  making 
openings  where  required  for  the  installation  of  the  equipment. 

The  bottom  of  each  column  box  is  to  have  one  side  left  open 
until  a  few  minutes  before  the  concrete  is  poured,  to  permit  of 
a  proper  adjustment  of  the  rods,  and  to  permit  also  any  necessary 
inspection  and  cleaning.  A  pocket,  also,  is  to  be  left  in  the  bottom 
of  girders  and  where  necessary  to  clean  out  chips,  etc.,  after  the 
columns  are  poured. 

All  forms  are  to  be  washed  of¥  with  water  from  a  hose,  or  by 
other  means,  some  time  before  and  again  immediately  before  the 
concrete  is  poured,  in  order  to  swell  the  wood  to  a  tight  fit  and  to 
remove  any  foreign  substance. 

Removal  of  Forms. — Forms  are  to  be  removed  carefully  in  order  , 
to  avoid  scarring  or  spalling  the  concrete,  and  to  prevent  heavy 
forms  from  falling  on  and  jarring  the  floors. 

The  concrete  is  to  be  sounded  frequently  with  a  hammer  during 
the  removal  of  the  forms  to  make  sure  that  the  concrete  is  sound 
and  well  set.  The  floor  above  is  not  to  be  heavily  loaded  at  the 
time  the  forms  are  removed.  The  props  are  not  to  be  removed 
from  under  any  floor  until  after  three  days  after  the  floor  next 
above  has  been  cast. 

Steel  Reinforcement. — The  girder,  beam,  column  and  column 
footing  reinforcement  is  to  consist  generally  of  square  cold-twisted 
or  other  deformed  steel  bars,  together  with  stirrups  and  supports  as 
required,  and  all  as  shown  on  the  drawings.  The  slab  reinforce- 
ment may  be  of  deformed  bars,  wired  together,  or  of  wire  mesh  or 
expanded-metal. 

Sections  other  than  those  shown  on  the  drawings  will  be  per- 
mitted to  be  used  in  a  manner  to  suit  dififerent  types  of  reinforce- 
ment. In  all  instances,  however,  the  net  sectional  area  of  the  metal 
reinforcement  is  to  be  the  same  as  that  designated  on  the  drawings, 


REINFORCED  CONCRETE. 


853 


•and  the  ''center  of  action"  of  all  the  steel  reinforcement  in  any  slab 
must  be  at  a  distance  of  i  inch  from  the  soffit  of  the  slab.  The 
reinforcement  of  the  beams  and  girders  is  to  have  at  least  2  inches 
of  concrete  protection  on  the  bottom  and  inches  on  the  sides; 
and  column  reinforcement  is  to  have  3  inches  of  such  concrete 
protection. 

If  cold-twisted  bars  are  used  the  reinforcement  is  to  be  what 
is  known  as  "medium  steel"  made  from  original  billets.  These 
bars  are  to  have  a  number  of  turns  per  foot?  an  elastic  limit  and 
•an  ultimate  tensile  strength  approximately  as  follows : 

No.  of  turns  Elastic  limit.         Ultimate  strength. 

Size.  per  foot.         Pounds  per  sq.  inch.  Pounds  per  sq.  inch, 

3/4 -inch  4  65,000  80,000 

"   3/        60.000  75,000 

V2  "   3       '    60,000  75.000 

Vs  "   2}i        60,000  75,000 

^   iVz  60,000  75,000 

Vs    "   1%  55,000  70,000 

I         "   I  50,000  70,000 

i>^-inches   ^  50,000  70,000 

1%      "    M  50,000  70,000 

The  bars  are  to  have  an  elongation  of  at  least  twelve  per  cent, 
measured  in  8  inches.  The  steel  is  to  bend  through  180  degrees 
over  a  pin  whose  diameter  is  i^/^  times  the  diameter  of  the  bar, 
without  fracture  on  the  outside  of  the  bent  portion. 

If  bars  of  other  forms  are  used,  they  are  to  be  of  higher  carbon 
steel  and  are  to  be  made  entirely  of  new  billets,  having  elastic 
limits,  ultimate  strengths,  elongations  and  bending  properties  as 
above. 

The  steel  is  to  be  tested  by  parties  appointed  by  the  architects 
and  as  often  as  the  latter  deem  necessary;  and  any  failure  of  the 
test  specimen  to  meet  the  requirements  is  to  be  considered  a  suffi- 
cient cause  for  rejection.  The  cost  of  tests  is  to  be  borne  by  the 
owner. 

None  of  the  steel  reinforcements  is  to  be  badly  rusted,  although 
:a  thin  film  of  rust  is  not  to  be  considered  objectionable.  If  the  steel 
is  covered  with  loose  or  scaly  rust,  dirt  or  cement  dri])pings  it  is  to 
be  cleaned  with  a  wire  brush.  All  bars  are  to  be  free  from  grease 
and  paint. 

Placing  the  Reinforcement. — All  the  steel  tension  members  for 
beams,  girders  and  lintels  are  to  be  fastened  or  wired  together  by 


854 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


any  suitable  methods,  and  the  stirrups  need  not  be  rigidly  fastened 
to  the  principal  members.  All  steel,  however,  is  to  be  set  in  the 
molds  before  the  concrete  is  poured,  and  the  reinforcement  is  to  be 
solidly  supported  or  hung  therein  in  such  manner  as  to  prevent 
shifting  about  when  the  concrete  is  tamped,  care  being  taken  to 
maintain  the  bars  in  their  proper  position. 

All  column  rods  are  to  lap  3  feet  at  their  junction  above  each 
floor  and  are  to  be  securely  wired  together. 

Each  floor  beam  and  roof  beam,  where  framed  into  a  girder  or 
column,  is  to  have  a  y^-'moh  tie-rod,  5  feet  long,  with  hook  ends 
*  turned  down  3  inches,  set  in  the  top  of  the  beam  and  projecting 

into  it ;  these  top  rods  are  to  extend  to  the  far  side  of  the  girder 
or  column. 

All  girders  are  to  have,  besides  a  full  bearing  at  the  columns  for 
the  reinforcement,  two  ^-inch  tie-rods,  each  6  feet  long,  with  hook 
ends  running  in  both  directions. 

A  sufficient  amount  of  the  reinforcement  for  beams,  girders  and 
lintels  is  to  be  bent  upward  toward  the  supports,  to  provide 
resistance  to  negative  bending  moments  at  or  adjacent  to  these 
points. 

,  Where  an  odd  number  of  bars  are  used  in  two  horizontal  planes, 

the  smaller  number  being  staggered  above  the  bottom  bars  and 
bent  up,  one  of  these  upper  bars  may  be  extended  3  feet  into  each 
of  the  adjoining  spans  and  take  the  place  of  the  5-feet  lap-rods 
above  specified. 

The  reinforcement  for  the  trough  construction  is  not  to  be  pro- 
vided with  stirrups.  One  end  of  each  rod  is  to  be  bent  up  at  an 
angle  of  45  degrees  at  a  distance  of  18  inches  from  the  middle  of 
the  girder.  The  straight  end  of  the  bent  portion  is  to  extend  over 
the  middle  of  the  girder  at  least  18  inches.  The  straight  end  of 
each  rod  also  is  to  extend  the  same  distance  past  the  middle  of  the 
girder.  In  placing  the  bars  in  the  trough  construction  the  pair  is 
to  be  so  arranged  that  the  bent  portions  come  at  opposite  ends,  thus 
.forming  a  complete  truss. 

Besides  the  regular  slab  reinforcement,  there  are  to  be  provided 
combination  spacer  and  stool-lock  wires  of  the  pattern  manufac- 
tured by  the  Philadelphia  Steel  and  Wire  Company.  These  are 
to  be  of  No.  13  spring  wire  and  are  to  be  spaced  2  feet  from 
center  to  center,  extending  in  lines  at  right-angles  to  the  slab-rods. 
If  approved  wire-mesh  or  expanded-metal  is  used  for  slab  rein- 


REINFORCED  CONCRETE. 


855 


forcement,  these  spacers  may  be  omitted.  There  are  also  to  be 
provided  rods  or  bars  of  the  same  section  as  the  slab  reinforcement 
and  5  feet  long,  placed  12  inches  apart  from  center  to  center,  over 
all  girders  and  at  right-angles  to  them. 

All  girders,  beams  and  lintels  are  to  be  provided  with  stirrups, 
of  sufficient  size  and  in  sufficient  numbers,  running  the  entire  length 
of  the  beams  and  girders.  There  are  to  be  a  sufficient  number  of 
them,  also,  to  resist  the  horizontal  shearing  stresses.  The  stirrups 
for  the  beams  and  girders  are,  in  all  instances,  to  be  long  enough 
to  extend  from  the  steel  reinforcement  in  the  lower  part  of  a  beam 
or  girder  a  distance  of  at  least  2  inches  into  the  slab,  and  they 
are  to  have  hook  ends  of  at  least  6-inch  projection.  Care  is  to  be 
taken  to  have  the  stirrups  of  beams,  girders  and  lintels  sufficiently 
long  to  engage  with  the  slab  reinforcement ;  and  the  stirrups  must 
either  hook  over  the  slab-rods  or  be  punched  or  looped  at  the  top 
so  that  these  rods  can  thread  through  them.  The  stirrups  are  to 
be  in  no  instance  more  than  4  feet  apart  at  the  middle  part  of  the 
span ;  and  are  to  be  closer  together  if  required  by  the  drawings 
or  if  necessary  to  resist  horizontal  shear. 

All  slab  reinforcement  is  to  lap  at  least  18  inches  at  the  joints 
over  bearings. 

The  contractor  is  to  provide  ^-inch  "hairpin"  stirrups  12  inches 
long,  to  be  placed  in  the  top  of  beams  and  girders  where  the  work 
is  stopped.  These  stirrups  are  to  straddle  the  slab  reinforcement, 
and  are  to  be  so  spaced  that  the  maximum  distance  between  them 
is- not  over  18  inches.  (These  are  not  necessary  if  the  work  is 
stopped  across  beams  and  girders  and  parallel  with  the  slab-rods. 
See  note  in  regard  to  ''Stopping  Work.") 

The  contractor  is  to  place  the  reinforcement  sufficiently  in 
advance  of  the  pouring  of  the  concrete  to  permit  of  inspection 
and  correction  by  the  architects  if  required. 

Sockets,  etc. — The  contractor  is  to  provide  and  imbed  through- 
out the  concrete  beams  and  girders  substantial  ^-inch  cast-steel  or 
malleable  iron  tapped  sockets  of  approved  design.  The  sockets  are 
to  be  bolted  to  the  bottom  of  the  molds,  placed  near  each  bearing, 
and  at  intermediate  distances  apart  of  not  more  than  5  feet,  or  as 
shown  on  drawings.  The  bolts  are  to  remain  the  property  of  the 
contractor. 

Small  cast-iron  sockets,  tapped  }4  of       inch,  are  to  be  provided 


856 


BUILDING  CONSTRUCTION.       (Ch.  XIII> 


in  all  floor  slab  panels,  about  ten  of  these  sockets  being  provided 
for  each  panel. 

If  the  trough  system  of  construction  is  employed,  three  slab- 
sockets  are  to  be  provided  for  every  other  beam. 

The  contractor  is  to  provide  at  the  middle  of  the  span  of  each 
girder,  and  near  the  under  side  of  the  slab,  four  ij^-inch  pipes 
extending  entirely  through  the  girder  and  placed  about  2  inches 
from  center  to  center.  He  is  to  provide  two  pieces  of  pipe  of 
similar  size  and  similarly  located  in  the  middle  of  the  span  of  all 
beams. 

All  sockets  and  pipes  are  to  be  located  to  meet  the  approval  of 
the  architect  or  his  representatives. 

For  the  trough  system,  pipes  are  to  be  provided  in  girders  only, 
at  the  bottom  of  the  trough  beams,  and  also  the  same  total  number 
of  sockets,  located  as  directed. 

The  contractor  is  to  state  the  allowance  that  is  to  be  made  if  all 
sockets  and  pipes  are  omitted,  as  required  by  the  "Form  of 
Proposal." 

Pipe  Sleeves. — The  contractor  is  to  place  sleeves  on  the  slab 
centering  in  order  to  provide  holes  for  the  use  of  plumbing,  steam 
and  sprinkler  pipes,  electrical  conduits,  etc.,  said  sleeves  being 
furnished  by  the  contractors  for  the  respective  kinds  of  work,  and 
drawings  also  being  furnished  to  the  contractor  showing  the  proper 
location  of  said  sleeves. 

Shop  Drazvings. — The  contractor  is  to  promptly  submit  shop 
drawings  in  duplicate  to  the  architect  for  approval ;  and  any 
changes  required  are  to  be  made  before  the  work  proceeds.  The 
shop  drawings  are  to  conform  to  the  architect's  drawings  as  to 
the  concrete  dimensions,  sectional  area  and  location  of  steel 
reinforcement,  although  equivalent  areas  may  be  permitted  in  order 
to  accommodate  bars  or  meshes  of  shapes  dififering  from  those 
indicated  on  the  drawings.  These  drawings  are  to  show  in  detail 
all  the  reinforcement,  the  manner  of  fastening  and  supporting  in 
the  forms,  the  position  of  bends  and  the  location  and  size  of  the 
stirrups. 

The  cement  is  to  be  provided  by  the  contractor  and  is  to  comply 
with  the  requirements  elsewhere  specified. 

The  sand  is  to  be  clean,  coarse  bank  sand,  Jersey  gravel  or  coarse 
river  gravel,  free  from  dirt  or  other  impurities,  and  containing 


REINFORCED  CONCRETE. 


857 


less  than  five  per  cent  of  loam  as  approved.  -Equal  parts  of  bar 
sand  and  Jersey  gravel  are  preferred. 

The  broken  stone  is  to  consist  of  clean  trap  rock  or  equally  hard 
stone,  not  of  lime  formation,  and  as  approved  by  the  architect.  The 
stone  used  for  footings  or  for  other  concrete  in  large  masses  may  be 
of  a  size  to  pass  through  a  i^^-inch  ring.  The  remaining  stone  is 
to  be  so  broken  that  it  will  pass  through  a  ^-inch  ring,  and  one- 
fourth  of  the  whole  is  to  be  less  than  one-half  the  maximum  size 
and  free  from  crusher  dust. 

If  the  stone  is  the  "run  of  the  crusher,"  varying  gradually  from 
about  ^-inch  size  to  the.  maximum,  the  proportion  of  sand  to  stone 
is  to  be  changed  to  meet  the  approval  of  the  architect. 

Proportions. — The  reinforced  concrete  is  to  be  mixed  in  the 
proportions  of  one  part  of  cement,  two  parts  of  sand  and  four 
parts  of  broken  stone.  Suitable  means  are  to  be  provided,  as 
approved  by  the  architect,  for  accurately  measuring  the  respective 
ingredients. 

Mixing. — An  approved  batch  mixer,  such  as  the  Ransome, 
McKelvey,  Smith  or  Chicago  types,  and  of  sufficient  capacity,  is  to 
be  used.  A  competent  man  is  to  be  in  charge  of  the  mixing.  Care 
is  to  be  exercised  in  adding  water  to  obtain  the  proper  consistency. 
Water  should  be  added  by  measure,  not  by  hose,  in  order  to  avoid 
non-uniformity. 

Where  the  quantity  of  work  is  small,  hand-mixing  may  be  per- 
mitted by  the  architect,  in  which  case  the  cement  and  sand  are  to 
be  turned  over  with  shovels  and  raked  twice  while  dry  and  twice 
w^hile  being  wet ;  the  stone  is  to  be  wet  separately,  and  the  whole 
turned  over  together  twice  with  shovels  and  rakes. 

Care  is  to  be  exercised  to  keep  the  gravel  or  sand  and  broken 
stone  in  distinct  and  separate  bins  or  piles. 

Test  Cubes. — The  contractor,  whenever  required  by  the  archi- 
tects, is  to  make  and  deliver  to  the  testing  laboratory  6-inch  concrete 
test  cubes,  said  cubes  being  made  from  the  regular  mixture  used 
in  the  work. 

Contractor's  Plant. — The  contractor  is  to  provide  a  suitable  hoist 
and  all  other  tools  and  implements  for  handling  the  concrete  with 
the  greatest  possible  despatch. 

Putting  the  Concrete  in  Place. — The  forms  are  to  be  thoroughly 
wet  some  time  before,  and  again  immediately  before  the  concrete 


858 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


is  poured,  in  order  that  they  may  swell  and  that  the  joints  may  be 
nearly  water-tight. 

The  concrete  is  to  be  well  tamped  in  position  and  the  molds 
thoroughly  filled  and  flat-spaded,  so  that  w^hen  the  forms  are 
■removed  the  work  will  be  smooth  on  the  face  and  solid  throughout. 

The  concrete  work,  where  exposed  in  fire-escapes  and  toilet- 
rooms,  is  to  have  the  rough  parts  smoothed  off  and  the  voids  filled 
flush,  leaving  a  smooth  finish.  The  tops  of  the  roof  slabs,  where 
there  is  reinforced  concrete  roof  construction,  are  to  be  made 
smooth  preparatory  to  the  laying  of  the  felt  roof.  All  columns, 
girders  and  beams  are  to  be  plumb,  straight  and  true  to  line,  special 
care  being  exercised  in  these  particulars  with  the  column  and  wall 
forms. 

•  In  stopping  the  work  over  beams  or  girders  the  slab-rods  are 
to  be  of  sufiicient  length  to  extend  over  and  furnish  a  bond  or  tie 
into  the  next  span  to  a  distance  at  least  12  inches  beyond  the  middle 
line  of  such  beams  or  girders. 

Columns  are  to  be  filled  to  the  bottom  of  the  beams,  the  concrete 
being  thoroughly  churned  with  a  pole.  After  being  filled  to  this 
height  they  are  to  set  for  several  hours  to  allow  for  settlement, 
after  which  the  beam,  girder  and  slab  forms  are  to  be  filled. 

Slabs  are  to  be  poured  on  the  same  day  the  girders  and  beams 
are  poured  and  before  the  concrete  has  begun  to  set  in  the  latter. 
In  case  any  slabs  are  not  poured  on  the  same  day,  the  girders  and 
beams  are  to  be  cleaned  with  water,  well  soaked  and  grouted  on 
top  with  neat  cement  rubbed  in  with  brushes  or  brooms ;  after  that 
a  thin  layer  of  cement  mortar  is  to  be  trowelled  in  and  the  slabs 
immediately  laid. 

In  joining  new  work  to  old  work  cement  mortar  is  to  be  used. 

The  contractor  is  to  remove  all  fins  from  the  concrete  work  after 
it  has  set  and  the  forms  have  been  removed. 

Stopping  Work. — In  stopping  a  day's  work  either  of  the  follow- 
ing methods  is  to  be  employed :  ( i )  Slabs  are  to  be  stopped  ofif 
along  the  middle  line  of  beams  and  girders,  pockets  are  to  be  left 
in  girders  to  form  bearings  for  beams  and  bearings  for  beams  and 
girders  are  to  be  formed  on  columns;  or  (2)  the  work  may  be 
stopped  where  necessary  across  the  middle  line  of  beams  and  girders 
and  on  slabs  parallel  with  the  main  slab-rods.  Molded  cement 
.  blocks  may  be  used  as  separating  dams  under  and  between  reinforc- 


REINFORCED  CONCRETE. 


859 


"ing  bars,  or  stiff  cement  dams  may  be  provided  under  and  between 
bars  and  wood  blocking  above  to  make  vertical  stops. 

Caution. — After  the  floor  slabs  have  begun  to  set  they  are  not 
to  be  walked  on  or  wheeled  over  until  hard,  as  otherwise  their 
strength  is  seriously  injured.  If  traffic  over  them  is  unavoidable, 
boards  are  to  be  provided  for  the  purpose  of  distributing  the 
weights. 

Laying  Concrete  m  Warm  Weather. — The  surface  of  concrete 
floors  laid  during  warm  weather  is  to  be  wet  twice  daily,  Sundays 
included,  during  the  first  week.  The  broken  stone,  if  hot  and  dry, 
is  to  be  wet  before  going  to  the  mixer. 

Laying  Concrete  in  Cold  Weather. — Reinforced  concrete  should 
not  be  laid,  if  it  is  possible  to  avoid  doing  so,  when  the  temperature 
is  below  33°  Fahr.  Extra  precautions  are  to  be  taken  during  cold 
weather.  The  water  should  be  heated  to  about  ioo°  Fahr.  The 
stone  and  sand,  if  covered  with  ice  or  snow,  should  be  heated  by 
steam  immediately  before  mixing. 

Should  the  temperature  drop  below  freezing,  or  the  United  States 
Weather  Bureau  predict  such  weather,  fresh  concrete  is  to  be 
protected  by  a  thick  layer  of  hay  or  straw  above  it  and  salamander 
fires  or  other  heat  provided  below.  The  openings  are  to  be  covered 
where  necessary. 

A  quantity  of  hay  or  straw  should  be  kept  on  hand  for  use  in 
covering  the  work. 

Concrete  frozen  while  fresh  and  found  to  be  injured  is  to  be 
removed  at  the  contractor's  expense. 

Forms  are  to  be  left  in  place  during  cold  weather  until  the  con- 
crete has  obtained  a  hard  natural  set. 

Lintels. — All  concrete  lintels,  where  they  extend  above  a  floor, 
are  to  be  cast  at  the  same  time  the  slabs  are  cast.    The  exterior 

faces  of  the  lintels  on  . —  Street  are  to  be  composed  of  a  1-2-4 

mixture  of  cement,  light  sand  and  crushed  granite.  The  granite 
pieces  are  to  be  not  over  a  ^-inch  size.  When  the  face-work  has 
thoroughly  set  it  is  to  be  dressed  with  6-cut  patent  hammers  to  a 
depth  sufficient  to  remove  the  outside  surface  entirely  and  to  leave 
exposed  the  texture  of  the  concrete  facing. 

Gussets. — The  roof  gussets  are  to  be  formed  where  shown  of 
concrete  composed  of  i  part  of  cement,  3  parts  of  sand  and  6 


86o 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


parts  of  clean,  hard  cinders,  laid  fairly  wet  and  with  a  smooth 
surface. 

Stair  Construction. — The  contractor  is  to  construct  the  stairs 
throughout,  where  indicated,  of  reinforced  concrete,  and  to  furnish 
all  the  necessary  metal  reinforcing  for  the  same. 

Any  necessary  sockets  for  pipe-railings  or  other  fastenings  are 
to Jbe  placed  where  required  during  the  construction  of  the  work. 

The  treads  and  risers  are  to  be  finished  with  a  cement  surface 
composed  of  i  part  of  cement  to  2  parts  of  sand.  The  surface  on 
the  treads  is  to  be  inches  thick  and  that  on  the  risers  an 
inch  thick.  The  concrete  steps  throughout  are  to  be  arranged 
with  a  projecting  and  rounded  nosing. 

All  stairs  and  landings,  where*  the  walls  are  to  be  plastered,  are 
to  have  a  cement  base,  6  inches  high  from  the  nosing,  formed 
along  the  wall  and  neatly  finished. 

Safety  Treads. — The  contractor  is  to  place  in  position  the 
''Mason  Safety  Treads,"  as  specified  under  that  heading. 

Platforms  of  Balconies. — Concrete  floors,  composed  of  i  part  of 
cement,  2  parts  of  sand  and  4  parts  of  clean,  hard  furnace  cinders, 
are  to  be  provided  upon  the  steel  framing  for  balconies ;  and  they 
are  to  be  finished  with  a  i-inch  surfacing  of  cement  as  elsewhere 
specified.  The  under  sides  of  platforms  are  to  have  a  cement  brush- 
finish. 

Copper  Ties. — The  contractor  is  to  provide  and  place  in  the 
forms  copper  ties  to  secure  the  face  brickwork  to  the  concrete  con- 
struction. These  copper  ties  are  to  be  %  by  iV-inch  in  cross-section 
by  8  inches  in  length.  The  ends  of  the  copper  ties  ^re  to  be  bent 
over  to  secure  a  hold  in  the  mortar  joints  of  the  brickwork.  The 
ties  are  to  project  at  least  4  inches  into  the  concrete  work,  and 
are  to  be  placed  so  that  there  will  be  one  tie  to  each  two  square 
feet  of  face  brickwork. 

Where  cesspools  are  marked,  as  in  areas,  etc.,  the  floors  are  to 
be  graded  to  drain  to  them. 

Wearing  Surface. — The  concrete  is  to  be  covered  with  a  i-inch 
surface  (i-inch  strips  are  to  be  used),  composed  of  Portland 
cement,  well  mixed  with  clean,  sharp,  coarse  granite  or  crushed 
trap-rock  and  sand  in  the  proportion  of  one  part  of  cement  to  one 
part  of  rock  and  one  part  of  sand  and  finished  with  an  even- 
floated  surface  of  uniform  shade,  and  laid  ofif  in  blocks  as  directed. 


REINFORCED  CONCRETE. 


All  cement  floors  on  reinforced  concrete,  where  cement  floors  are 
marked,  including  toilet-rooms,  are  to  be  similarly  finished  with  a 
i-inch  cement  finish  ;  this  and  any  other  cement  finish  on  reinforced 
concrete  slabwork  is  to  be  placed  on  2  inches  of  cinder  concrete 
filling  composed  of  materials  as  elsewhere  specified. 

The  cement  finish  or  wearing  surface  is,  in  all  cases,  to  be  laid 
before  the  concrete  base  has  set,  in  order  to  obtain  a  perfect  bond.. 

The  floors  of  toilet-rooms  are  to  be  graded  to  drain  and  are  to 
be  finished  with  a  2 -inch  coved  base  around  the  walls  and  par- 
titions. The  coved  base  is  to  be  finished  flat  on  top  to  receive  a 
%-inch  rubbed-slate  base-board. 

Concrete  Sills,  Copings,  etc. — Concrete  sills  are  to  be  provided 
under  all  tin-lined  fire-doors  and  wherever  marked  on  the  plans.. 
These  sills  are  to  be  of  sufficient  width  to  cover  the  threshold  and 
the  thickness  of  the  doors  and  are  to  have  angle  edges  as  specified 
under  'Tron  and  Steel  Work."  All  sills  are  to  be  constructed  a.s 
shown  on  detail  drawings. 

A  concrete  coping,  at  least  10  inches  in  thickness,  is  to  be  pro- 
vided and  placed  on  the  top  of  the  stack,  and  finished  on  top  with 
a  smooth  surface  and  wash. 

Cinder  Concrete  Filling. — Cinder  concrete  is  to  be  provided 
between  wood  sleepers  where  the  plans  show  wood  floors  laid  over 
reinforced  concrete.  This  concrete  is  to  be  brought  up  flush  with 
the  top  of  the  sleepers.  All  filling  is  to  be  made  of  clean  furnace 
clinkers,  sand  and  cement,  in  the  proportions  of  one  of  cement^ 
three  of  sand  and  seven  parts  of  cinders.  The  cinder  concrete  is. 
to  be  well  manipulated  and  tamped  in  position. 

Cinder  concrete  mixed  as  abgve  is  to  be  placed  also  upon  the 
reinforced  concrete  slabs,  where  cement  floors  are  marked  to 
receive  the  cement  finish. 

Fire-proofing. — The  contractor  is  to  provide  and  place  concrete 
fire-proofing  for  all  steel  beams,  girders  or  other  structural  steel 
work  where  the  same  is  required  by  the  plans,  and  is  to  provide 
all  the  necessary  expanded-metal  and  light  metalwork  for  securing 
the  same  in  place. 

Cement  Pavements. — The  contractor  is  to  repave  the  sidewalks 
where  cement  pavements  are  called  for  by  the  plans.  These  pave- 
ments are  to  be  laid  on  16-inch  beds  of  clean  boiler  cinders, 
thoroughly  tamped  or  rolled,  and  are  to  consist  of  concrete  4  inches. 


:862  BUILDING  CONSTRUCTION.       (Ch.  XIII) 

in  thickness  and  of  the  same  composition  as  specified  for  similar 
work  in  the  basement.  The  finishing  coat  is  to  be  i  inch  in  thick- 
ness, laid  with  strips,  marked  off  in  blocks  and  indented.  The 
■concrete  for  the  base  of  the  pavement  is  to  be  cut  in  blocks  all  the 
way  through.  Expansion-joints  are  to  be  provided  every  fifty  feet 
and  filled  with  asphalt. 

The  finishing  coat  is  to  be  put  on  before  the  concrete  base  has  its 
final  set,  and  the  entire  pavement  is  to  be  true  and  properly  graded. 

A  concrete  curb  is  to  be  provided  throughout  as  required  by  the 
plans. 

The  curb  is  to  be  placed  in  the  ground  to  a  depth  of  at  least  2 
feet  6  inches  and  smoothly  finished  with  a  i-inch  coat  of  cement 
finish,  as  specified  for  the  basement  floor.  It  is  to  be  provided  with 
a  quarter-round  galvanized-iron  armored  corner-bead,  made  for 
this  purpose  and  of  an  approved  pattern.  This  corner-bead  is  to  be 
furnished  as  specified  under  this  heading. 

CONCRETE  BUILDING  BLOCKS.* 

706.  RULES  AND  REGULATIONS  GOVERNING  THE 
USE  AND  MANUFACTURE  OF  HOLLOW  CONCRETE 
BUILDING  BLOCKS.  (See  also  Article  633.)—!.  Composition 
and  Use. — Hollow  concrete  building  blocks  may  be  used  for  build- 
ings six  stories  or  less  in  height  where  said  use  is  approved  by  the 
Bureau  of  Building  Inspection ;  provided,  however,  that  such 
blocks  are  composed  of  at  least  one  (i)  part  of  standard  Portland 
cement,  and  not  more  than  five  (5)  parts  of  clean,  coarse,  sharp 
sand  or  gravel,  or  of  a  mixture  of  at  least  one  (i)  part  of  Portland 
cement  to  five  (5)  parts  of  crushed  rock  or  other  suitable,  aggre- 
gate ;  and  provided,  further  that  this  section  does  not  permit  the 
use  of  hollow  blocks  in  party-walls.  Said  party-walls  are  to  be 
built  solid. 

2.  Percentage  of  Hollow  Spaces. — All  material  is  to  be  fine 
enough  to  pass  through  a  ^-inch  ring  and  is  to  be  free  from  dirt 
<or  foreign  matter.  The  material  composing  such  blocks  is  to  be 
properly  mixed  and  manipulated,  and  the  volume  of  hollow  spaces 
in  said  blocks  is  not  to  exceed  the  percentage  given  in  the  following 

*  Taken  and  adapted  from  the  "Laws  and  Ordinances  Relating  to  the  Bureau  of 
Building  Inspection"  of  the  City  of  Philadelphia,  Pa.,  1907.  Philadelphia  and  Denver  are 
the  first  two  cities  which  have  given  exhaustive  study  to  concrete  building  blocks  with  a 
view  to  formulating  regulations  governing  their  use  in  building  construction. 


CONCRETE  BLOCKS. 


863 


table  for  walls  of  different  heights.  In  no  case  are  the  walls  or 
webs  of  a  block  to  be  less  in  thickness  than  one-fourth  of  the  height. 
The  figures  given  in  the  table  represent  the  percentage  of  such 
hollow  spaces  for  walls  of  different  heights. 


Stories. 

ISt. 

2d. 

3d. 

4th. 

5tli 

6th. 

I  and  2 

33 

33 

3  and  4 

25 

33 

33 

33 

5  and  6 

20 

25 

25 

33 

33 

33 

3.  Thickness  of  Walls. — The  thicknesses  of  walls  for  any  build- 
ing in  which  hollow  concrete  blocks  are  used  are  to  be  not  less, 
than  is  required  by  law  for  the  thicknesses  of  brick  walls. 

4.  Bonding  and  Tests. — Where  the  face  only  is  of  hollow  con- 
crete building  blocks  and  the  backing  is  of  brick,  the  facing  of 
the  hollow  concrete  blocks  is  to  be  strongly  bonded  to  the 
brickwork  either  with  headers  projecting  four  (4)  inches  into  ihe 
brickwork,  every  fourth  course  being  a  heading  course,  or  with 
approved  ties  ;  no  brick  backing  is  to  be  less  than  eight  (8)  inches, 
in  thickness.  Where  the  walls  are  made  entirely  of  hollow  concrete 
blocks,  but  where  the  said  blocks  have  not  the  same  width  as  the 
walls,  every  fifth  course  is  to  extend  through  the  wall,  forming  a 
secure  bond.  All  walls  in  which  blocks  are  used  are  to  be  laid  up 
in  Portland  cement  mortar. 

5.  Age  of  Blocks. — All  hollow  concrete  building  blocks  before- 
being  used  in  the  construction  of  any  building  in  the  City  of  Phila- 
delphia must  have  attained  the  age  of  at  least  three  (3)  weeks. 

6.  Blocks  Solid  Under  Concentrated  Loads. — Wherever  girders 
or  joists  rest  upon  walls  so  that  there  is  a  concentrated  load  of 
over  two  (2)  tons  on  the  blocks,  those  supporting  the  girder  or 
joists  are  to  be  made  solid.  Where  such  concentrated  load  exceeds 
five  (5)  tons,  the  blocks  for  two  (2)  courses  below,  and  for  a 
distance  of  at  least  eighteen  inches  on  each  side  of  said  girder,  are 
to  be  made  solid.  Where  the  load  on  the  wall  from  the  girder 
exceeds  five  (5)  tons,  the  blocks  for  three  (3)  courses  beneath  it 
are  to  be  made  solid  with  a  material  similar  to  that  used  in  the 
blocks.  Wherever  walls  are  decreased  in  thickness  the  top  course 
of  the  thicker  wall  is  to  be  solid. 

7.  Maximum  Load  and  Crushing  Strength. — Provided  always: 
that  no  wall,  or  any  part  thereof,  composed  of  hollow  concrete 
blocks  is  to  be  loaded  in  excess  of  eight  (8)  tons  per  superficial 


B64 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


foot  of  the  area  of  such  blocks,  including  the  weight  of  the  wall ; 
and  that  no  blocks  having  an  average  crushing  strength  of  less  than 
i,ooo  pounds  per  square  inch  of  area  at  the  age  of  twenty-eight  (28) 
days  are  to  be  used ;  and  that  no  deduction  is  to  be  made  for  the 
hollow  spaces  in  figuring  the  area. 

8.  Piers,  Buttresses,  Sills  and  Lintels. — All  piers  and  buttresses 
which  support  loads  in  excess  of  five  (5)  tons  are  to  be  built  of 
solid  concrete  blocks  for  such  distance  below  as  may  be  required 
by  the  Bureau  of  Building  Inspection.  Concrete  lintels  and  sills 
are  to  be  reinforced  with  iron  or  steel  rods  in  a  manner  satisfactory 
to  the  Bureau  of  Building  Inspection,  and  any  lintels  spanning  over 
4  feet  6  inches  in  the  clear  are  to  rest  on  solid  concrete  blocks. 

9.  Testing  Blocks  and  Filing  Certificates. — Provided :  that  no 
ihollow  concrete  building  blocks  are  to  be  used  in  the  construction 
of  any  building  in  the  City  of  Philadelphia,  unless  the  maker  of 
said  blocks  has  submitted  his  product  to  the  full  test  required  by 
the  Bureau  of  Building  Inspection,  and  has  placed  on  file  with 
'said  Bureau  of  Building  Inspection  a  certificate  from  a  reliable 
testing  laboratory  showing  that  samples  from  the  lot  of  blocks  to 
be  used  have  successfully  passed  the  requirements  of  the  Bureau 
of  Building  Inspection,  and  that  a  full  copy  of  the  test  has  been 
filed  with  the  Bureau. 

10.  Brand. — A  brand  or  mark  of  identification  is  to  be  impressed 
in,  or  otherwise  permanently  attached  to,  each  block  for  purposes 
of  identification. 

11.  Approval  Limited  to  Four  Months. — No  certificate  of 
approval  is  to  be  considered  in  force  for  more  than  four  months, 
unless  there  be  filed  with  the  Bureau  of  Building  Inspection,  in  the 
City  of  Philadelphia,  at  least  once  every  four  months  following,  a 
certificate  from  some  reliable  physical  testing  laboratory  showing 
that  the  average  of  three  (3)  specimens  tested  for  compression, 
and  three  (3)  specimens  tested  for  transverse  strength,  comply  with 
the  requirements  of  the  Bureau  of  Building  Inspection  of  the  City 
of  Philadelphia.  The  samples  are  to  be  selected  either  by  a  Build- 
ing Inspector  or  by  the  laboratory  from  blocks  actually  going  into 
construction  work.  Samples  are  not  to  be  furnished  by  the  con- 
tractors or  builders. 

12.  Tests  of  Cements  Used. — The  manufacturer  and  user  (or 
•either  the  manufacturer  or  the  user)  of  any  such  hollow  concrete 
blocks  as  are  mentioned  in  this  regulation,  at  any  and  all  times 


CONCRETE  BLOCKS. 


865 


required,  are  to  have  such  tests  made  of  the  cements  used  in  making- 
such  blocks,  or  such  further  tests  of  the  completed  blocks,  or  of 
each  of  these,  at  their  own  expense,  and  under  the  supervision  of 
the  Bureau  of  Building  Inspection,  as  the  Chief  of  said  Bureau 
requires. 

13.  Portland  Cement  to  Be  Used. — The  cement  used  in  making 
said  blocks  is  to  be  Portland  cement,  capable  of  passing  the  minimum 
requirements  as  set  forth  in  the  "Standard  Specifications  for 
Cement"  by  the  American  Society  for  Testing  Materials. 

14.  Defective  Blocks  Condemned. — Any  and  all  blocks,  samples 
of  which,  on  being  tested  under  the  direction  of  the  Bureau  of 
Building  Inspection,  fail  to  stand  at  twenty-eight  (28)  days  the 
tests  required  by  this  regulation,  are  to  be  marked  ''condemned'* 
by  the  manufacturer  or  user,  and  are  to  be  destroyed. 

15.  Inspection  of  Blocks  and  Testing  of  Samples. — No  concrete 
blocks  are  to  be  used  in  the  construction  of  any  building  in  the 
City  of  Philadelphia  until  they  have  been  inspected,  and  average 
samples  of  the  lot  tested,  approved  and  accepted  by  the  Chief  of 
Building  Inspectors. 

706.  SPECIFICATIONS  GOVERNING  THE  METHOD  OF 
TESTING  HOLLOW  BLOCKS.— i.  General  Considerations.-^ 
These  regulations  are  to  apply  to  all  such  new  materials  as  are 
used  in  building  construction  in  the  same  manner  and  for  the  same 
purposes  as  stone,  brick  and  concrete  are  now  authorized  by  the 
building  laws,  to  be  used,  when  said  new  materials  to  be  substi- 
tuted depart  from  the  general  shape  and  dimensions  of  ordinary 
building  bricks ;  and  they  are  to  apply  more  particularly  to  that 
form  of  building  material  known  as  ''hollow  concrete  blocks," 
manufactured  from  cement  and  a  certain  addition  of  sand,  crushed 
stone  or  similar  material. 

2.  Applications  Filed. — Before  any  such  material  is  used  in 
buildings,  an  application  for  its  use  and  for  a  test  of  the  same  is 
to  be  filed  with  the  Chief  of  the  Bureau  of  Building  Inspection.  A 
description  of  the  material,  a  brief  outline  of  its  manufacture  and 
the  proportions  of  the  materials  used  are  to  be  embodied  in  the 
application. 

3.  Tests  Required. — The  material  is  to  be  subjected  to  the  fol- 
lowing tests :  transverse,  compression,  absorption,  freezing  and 
fire.  Additional  tests  may  be  called  for  when,  in  the  judgment  of 
the  Chief  of  the  Bureau  of  Building  Inspection,  the  same  may  be 


866 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


necessary.  All  such  tests  are  to  be  made  in  some  laboratory  of 
recognized  standing,  under  the  supervision  of  the  engineer  of  the 
Bureau  of  Building  Inspection.  The  tests  are  to  be  made  at  the 
expense  of  the  applicant. 

4.  Results  of  Tests  Filed. — The  results  of  the  tests,  whether  sat- 
isfactory or  not,  are  to  be  placed  on  file  in  the  Bureau  of  Building 
Inspection.    They  are  to  be  open  to  inspection  upon  application  to- 
the  Chief  of  the  Bureau,  but  need  not  necessarily  be  published. 

5.  Samples  for  Tests. — For  the  purposes  of  the  tests  at  least 
twenty  (20)  samples  or  test  pieces  are  to  be  provided.  Such 
samples  must  represent  the  ordinary  commercial  product.  They 
may  be  selected  from  stock  by  the  Chief  of  the  Bureau  of  Building 
Inspection,  or  his  representative,  or  may  be  made  in  his  presence, 
at  his  discretion.  The  samples  are  to  be  of  the  regular  size  and 
shape  used  in  construction.  In  cases  where  the  material  is  made 
and  used  in  special  shapes  and  forms,  too  large  for  testing  in  the 
ordinary  machines,  smaller-sized  specimens  are  to  be  used,  as  may 
be.  directed  by  the  Chief  of  Building  Inspection,  to  determine  the 
physical  characteristics  specified  in  Section  3. 

6.  Tests  to  Be  Made  in  Sixty  Days. — The  samples  may  be  tested 
as  soon  as  desired  by  the  applicant,  but  in  no  case  later  than  sixty 
(60)  days  after  manufacture. 

7.  Weight. — The  weight  per  cubic  foot  of  the  material  is  to  be 
determined. 

8.  Manner  of  Testing. — Tests  are  to  be  made  in  series  of  at  least 
five,  except  that  in  the  fire  tests  a  series  of  two  (four  samples)  are 
sufficient.  Transverse  tests  are  to  be  made  on  full-sized  samples. 
Half  samples  may  be  used  for  the  crushing,  freezing  and  fire  tests. 
The  remaining  samples  are  to  be  kept  in  reserve,  in  case  unusual 
flaws  or  exceptional  or  abnormal  conditions  make  it  necessary  to 
discard  certain  of  the  tests.  All  samples  are  to  be  marked  for 
identification  and  comparison. 

9.  Transverse  Test. — The  transverse  test  is  to  be  made  3S  fol- 
lows: The  samples  are  to  be  placed  flatwise  on  two  rounded  knife- 
edge  bearings  set  parallel  and  seven  inches  apart.  Loads  transmitted 
through  a  similar  rounded  knife-edge  are  then  to  be  applied  on  top, 
midway  between  the  supports,  until  the  sample  is  ruptured.  The 
modulus  of  rupture  is  then  to  be  determined  by  multiplying  the 
total  breaking  load  in  pounds  by  twenty-one  (three  times  the  dis- 
tance between  the  supports,  in  inches)  and  by  dividing  the  product 


CONCRETE  BLOCKS. 


867 


thus  obtained  by  twice  the  product  of  the  width  In  inches  by  the 
square  of  the  depth  in  inches.  The  formula  to  be  used  for  the 
modukis  of  rupture  is 


2bd' 


No  allowance  is  to  be  made  for  the  hollow  spaces  in  figuring  the 
modulus  of  rupture. 

10.  Compression  Test. — The  compression  test  is  to  be  made  as 
follows:  Samples  are  to  be  so  cut  from  blocks  that  they  contain 
a  full  web  section.  The  sample  is  to  be  carefully  measured,  bedded 
flatwise  in  plaster  of  Paris  to  secure  a  uniform  bearing  in  the  testing 
machine  and  then  crushed.  The  total  breaking-load  is  to  be  then 
divided  by  the  area  in  compression  in  square  inches.  No  deduc- 
tion is  to  be  made  for  hollow  spaces ;  the  area  is  to  be  considered 
as  the  product  of  the  width  by  the  length. 

11.  Absorption  Test. — The  absorption  test  is  to  be  made  as  fol- 
lows :  The  sample  is  to  be  first  thoroughly  dried  to  a  constant 
weight.  The  weight  is  to  be  carefully  recorded.  It  is  then  to  be 
placed  in  a  pan  or  tray  of  water,  face  downward,  to  a  depth  of  not 
more  than  ^  an  inch.  It  is  to  be  again  carefully  weighed  at  the 
following  periods :  thirty  minutes,  four  hours  and  forty-eight 
hours,  respectively,  from  the  time  of  immersion,  being  replaced  in 
the  water  in  each  case  as  soon  as  the  weight  is  taken.  Its  com- 
pressive strength,  while  still  wet,-  is  then  to  be  determined  at  the 
end  of  the  forty-eight-hour  period  in  the  manner  specified  in 
Section  10. 

12.  Freezing  Test. — The  freezing  test  is  made  as  follows:  The 
sample  is  to  be  immersed,  as  described  in  Section  11,  for  at  least 
four  hours  and  then  weighed.  It  is  then  to  be  placed  in  a  freezing 
mixture  or  in  a  refrigerator,  or  otherwise  subjected  to  a  tempera- 
ture lower  than  15  degrees  Fahr.  for  at  least  12  hours.  It  is  then 
to  be  removed  and  placed  in  water,  where  it  is  to  remain  for 
at  least  one  hour,  the  temperature  of  the  water  being  at  least  150 
degrees  Fahr.  This  operation  is  to  be  repeated  ten  (10)  times, 
after  which  the  sample  is  to  be  again  weighed  while  still  wet  from 
the  last  thawing.  Its  crushing  strength  is  then  to  be  determined 
as  called  for  in  Section  10. 

13.  Fire  Test. — The  fire  test  is  to  be  made  as  follows:  Two- 


868 


BUILDING  CONSTRUCTION.       (Ch.  XIII) 


Tramples  are  to  be  placed  in  a  cold  furnace  in  which  the  temperature 
is  gradually  raised  to  1700  degrees  Fahr.  The  test  piece  is  to  be 
subjected  to  this  temperature  for  at  least  30  minutes.  One  of  the 
samples  is  then  to  be  plunged  into  cold  water  (whose  temperature 
is  from  about  50  to  60  degrees  Fahr.)  and  the  results  noted.  The 
second  sample  is  to  be  permitted  to  cool  gradually  in  air  and  the 
results  noted. 

14.  Modulus  of  Rupture  and  Ultimate  Compressive  Strength. — 
The  following  requirements  are  to  be  met  to  secure  an  acceptance 
of  the  materials :  The  modulus  of  rupture  for  concrete  blocks  28 
days  old  is  to  average  150  and  is  not  to  fall  below  100  pounds  per 
square  inch  in  any  case.  The  ultimate  compressive  strength  at  28 
days  is  to  average  1,000  pounds  per  square  inch  and  is  not  to  fall 
below  700  pounds  per  square  inch  in  any  case.  The  percentage  of 
absorption  (being  the  weight  of  water  absorbed  divided  by  the 
weight  of  the  dry  sample)  is  not  to  average  higher  than  15  per  cent 
and  is  not  to  exceed  20  per  cent  in  any  case.  The  reduction  of 
compressive  strength  is  to  be  not  more  than  33^  per  cent,  except 
that  when  the  lower  ^figure  is  still  above  1,000  pounds  per  square 
inch  the  loss  in  strength  may  be  neglected.  The  freezing  and 
thawing  process  is  not  to  cause  a  loss  in  weight  greater  th^  10  per 
cent,  nor  a  loss  in  strength  of  more  than  33^  per  cent;  except  that 
when  the  lower  figure  is  still  above  1,000  pounds  per  square  inch, 
the  loss  in  strength  may  be  neglected.  The  fire  test  is  not  to  cause 
the  material  to  disintegrate. 

15.  Conditions  for  Approval. — The  approval  of  any  material  is 
to  be  given  under  the  following  conditions  only : 

a.  A  brand  mark  for  identification  is  to  be  impressed  on,  or 
otherwise  attached  to,  the  material. 

b.  A  plant  for  the  production  of  the  material  is  to  be  in  full 
operation  when  the  official  tests  are  made. 

c.  The  name  of  the  firm  or  corporation  and  the  names  of  the 
responsible  officers  are  to  be  placed  on  file  with  the  Chief  of  the 
Bureau  of  Building  Inspection,  and  changes  in  same  promptly 
reported. 

d.  The  Chief  of  the  Bureau  of  Building  Inspection  may  require 
full  tests  to  be  repeated  on  samples  selected  from  the  open  market  • 
when,  in  his  opinion,  there  is  any  doubt  as  to  whether  the  product 
is  up  to  the  standard  of  these  regulations ;  and  the  manufacturer 
is  to  submit  to  the  Bureau  of  Building  Inspection,  once  in  at  least 


CONCRETE  BLOCKS. 


869 


•every  four  months,  a  certificate  of  tests  showing  that  the  average 
resistance  of  three  specimens  to  cross-breaking  and  crushing  are 
not  below  the  requirements  of  these  regulations.  Such  tests  are  to 
be  made  by  some  laboratory  of  recognized  standing  on  samples 
selected  either  by  a  Building  Inspector  or  by  the  laboratory,  from 
material  actually  going  into  the  construction,  and  not  on  those 
furnished  by  the  manufacturer. 

e.  In  case  the  results  of  tests  made  under  this  condition  (d) 
show  that  the  standard  of  these  regulations  is  not  maintained,  the 
approval  of  this  Bureau  for  the  manufacture  of  said  blocks  is  to  be 
at  once  suspended  or  revoked. 


APPENDIX. 


The  tables  of  the  Appendix  relate  to  and  give  additional  data 
on  the  subjects  relating  principally  to  cements,  building  stones  and 
baked-clay  products  treated  in  Chapters.  IV,  V,  VII  and  VIII. 

TABLE  A.* 

The  following  table  shows  the  quantity  and  the  value  of  the 
natural  cement  made  in  the  United  States  in  1904,  1905  and  1906: 
The  combinations  of  figures  for  total  State  productions  neces- 

TABLE  A.* 


Production^  in  Barrels,  of  Natural  Cement  in  1904,  1905  and 

1906,  BY  States. 


State 

1904 

1905 

1906 

No. 
of 
w'ks 

Quantity 

Value 

No. 

of 
w'ks 

Quantity 

Value 

No. 
of 
w'ks 

Quantity 

Value 

Georgia  

Kansas  

Kentucky  

Maryland  

2 
3 

13 
2 
2 
4 
2 
1 

19 
1 
1 
5 
1 
2 
1 
2 

66,500 
360,308 
735,906 
210,922 
264,104 

65,000 
138,000 

$37,750 
113,000 
367,953 
79,456 
132,052 
32,500 
65,620 

3 
3 
12 
2 
2 
4 
2 

A 

1 
1 

5 
1 
2 
1 
2 

89,167 
368,645 
527,600 
230,686 
207,500 

55,324 
115,314 

151,040 
116,549 
211,040 
110,750 
83,000 
28,694 
57,643 

3 
3 

12 
2 
2 
4 
2 
1 

16 
1 
1 
4 
1 
1 

al80,500 
365,843 
600,000 
238,311 
170,194 
a63,350 

S98.075 
118,221 
240,000 
129,781 
95,539 
32,675 

Nebraska  

New  York. 
North  Dakota. 
Ohio  

1,911,402 

1,138,667 

1,926,837 

1,332,809 

al,515,866 

1,055,785 

64,791 
748,057 

51,235 
306,555 

Pennsylvania. . 
Texas  

770,897 

298,533 

744,403 

560,534 

Virginia  

93,292 

59,619 

West  Virginia. 
Total 

250,000 

125,000 

139,128 

63,737 

2 

177,330 

92,560 

61 

64,866,331 

2,450,150 

58 

c4,473,049 

2,413,052 

55 

4,055,797 

2,423,170 

a  As  shown  by  the  returns,  a  small  quantity  of  hydraulic  lime  was  produced  in  Georgia, 
Maryland  and  New  York.  The  combined  output  of  these  States  is  40,800  barrels,  valued  at 
$19,300,  and  is  included  in  the  total  of  natural  cement  production  for  1906. 

b  The  States  combined  for  1904  and  1905  are  noted  in  the  text  of  the  reports  for  those  years. 

c  The  States  wherein  the  cement  product  was  combined  with  that  of  some  other  State  for 
1906  are  given  in  the  text  of  the  government  report. 


*  Taken  from  "Mineral  Resources  of  the  United  States,"  for  the  year  1906. 

870 


APPENDIX. 


871 


5ary  to  conceal  individual  outputs  in  1906  are  as  follows: 

Wisconsin,  North  Dakota  and  Minnesota  are  grouped  together; 
Kentucky,  Ohio  and  Virginia  form  a  second  group ;  and  Texas  and 
Kansas  complete  the  combinations.  As  is  the  custom,  the  State 
making  the  largest  contribution  to  the  total  in  these  groups  carries 
the  entire  quantity. 

New  York  ranks  first,  as  always,  in  this  production,  with  Penn- 
sylvania second,  and  Indiana  third. 


TABLE  B.* 

Geographic  Distribution  of  the  Portland  Cement  Industry  in 

1905  and  1906. 


Number  of 
plants  opera- 
ting 

'   Output,  in  barrels 

Percentage  of 
total  output 

1905 

1906 

1905 

1906 

1905 

1906 

West  

South  

Total  

30 
32 
7 
3 
7 

31 
34 
8 
4 
7 

84 

19,589,675 
10,723,802 
2,470,349 
1,225,429 
1.237,557 

25,483,025 
14,030,665 
3,834.656 
1,310,435 
1,804,643 

55.6 
30.4 
7.0 
3.5 
3.5 

54.9 
30.2 
8.2 
2.8 
3.9 

79 

35.246,812 

46,463.424 

100.00 

100.0 

*  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


TABLE  C* 

The  following  table  is  designed  to  show  the  quantity  and  value 
of  the  Portland  cement  made  in  those  States  which  were  producers 
in  1904,  1905  and  1906: 

As  heretofore,  the  production  of  those  plants  which  are  the  only 
ones  in  their  States  are  so  combined  that  the  figures  may  not  be 
published  in  a  form  which  will  reveal  individual  production. 

The  cards  of  request  for  figures  and  information  annually  issued 
state  that  all  facts  and  data  sent  in  are  regarded  as  confidential 
unless  there  is  a  special  understanding  to  the  contrary.  Individual 
figures  showing  quantity  or  value  of  production  are  very  seldom 
published,  and  if  in  rare  instances  such  a  publication  is  considered 
desirable  it  is  never  made  without  express  permission  from  the 
producer. 


872  BUILDING  CONSTRUCTION. 

In  the  following  table  the  outputs  of  Alabama,  Georgia,  West 
Virginia,  and  Virginia  are  combined ;  the  production  of  Kentucky 
is  given  with  that  of  Missouri;  Colorado,  Utah,  Texas,  South 
Dakota,  and  Arizona  are  combined ;  and  in  each  instance  the  total 
sum  of  the  combined  figures  is  placed  against  the  name  of  the 
State  that  contributed  the  largest  quantity  of  cement  to  that  totaL 

In  1906  there  was  great  activity  in  the  Portland  cement  industry- 
States  which  have  heretofore  not  produced  cement  began  the 
erection  of  Portland  cement  plants;  mills  that  were  making  their 
initial  runs  did  well ;  and  some  of  the  centers  of  activity  increased 
their  productive  capacity,  either  by  constructing  new  plants  or  by 
remodeling  old  ones. 

Indian  Territory,  Iowa  and  Arizona  appear  in  1906  for  the  first 
time  in  the  list  of  cement-producing  States. 

TABLE  C* 


Production,  in  Barrels,  of  Portland  Cement  in  the  United- 
States  in  1904- 1906,  by  States. 


1904  d 

1905  a 

1906  h 

No. 

State 

No. 

No. 

of 

of 

Quantity 

Value 

of 

Quantity 

Value 

active 

Quantity 

Value 

w'ks 

w'ks 

w'ks 

Alabama  

1 

1 

1 

1 

1 

1 

California.  .  .  . 

3 

1,014,558 

$1,446,909 

3 

1,225,429 

$1,671,816 

3 

1,310,435 

$2,110,294 

1 

490,294 

638,167 

1 

786,232 

1,172,027 

1 

1,146,396 

2,034,382 

1 

1 

1 

Illinois  

5 

1,326,794 

1,449,114 

5 

1,545.500 

1,741,150 

4 

1,858,403 

2,461,494 

4 

1,350,714 

1,232,071 

6 

3,127,042 

3,134,219 

6 

3,951,836 

4,964,855 

Kansas  

2 

2,643,939 

2,134,612 

4 

4 

3,020,862 

3,908,708. 

Kentucky..  .  . 
Michigan  

.  1 

1 

1 

16 

2,247,160 

2,365,656 

16 

2,773,283 

2,921,507 

14 

3,747,525 

4,814,965 

Missouri  

2 

2 

3,879,542 

4,164,974 

2 

3,350,000 

3,260,000 

New  Jersey.. . 

3 

2,799,419 

2,099,564 

3 

3,654,777 

2,775,768 

3 

4,423  648 

4,445,364 

New  York.. .  . 

11 

1,362,514 

1,257,561 

11 

2,111,411 

2,044,253 

9 

2,414,362 

2,725,744 

Ohio  

7 

910,297 

987,899 

8 

1,312,977 

1,390,481 

8 

1,422.901 

1,709,918 

Pennsylvania; 

17 

11,496,099 

8,969,206 

18 

13,813,487 

11,195,940 

19 

18,645,015 

18,598,439 

South  Dakota 

1 

1 

1 

Texas  

2 

3 

2 

Utah  

1 

1 

1 

.  .  .  1  . 

1 

864,093 

774,360 

1 



1,017,132 

1,033,732 

1 

1,172,041 

1,432,023 

1 

1 

West  Virginia 

1 

1 

1 

Total  

81 

26,505,881 

23,355,119 

89 

35,246,812 

33,245,867 

84 

46,463,424 

52,466,186 

a  The  States  combined  for  1904  and  1905  are  mentioned  in  the  text  of  the  reports  for  those 
years. 

h  The  States  combined  for  1906  are  given  in  the  text  below. 


♦  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


APPENDIX, 


873 


TABLE  D.* 

The  table  which  follows  shows  the  growth  of  the  Portland 
cement  industry  in  the  United  States.  Its  form  was  originally 
determined  by  the  fact  that  the  cement  production  was  confined 
mainly  to  certain  well-defined  centers,  but  changes  in  conditions 
since  1900  have  necessitated  a  change  in  form. 

Under  "All  Other  Sections"  is  included  the  production  of  Ala- 
bama, Arizona,  California,  Colorado,  Georgia,  Illinois,  Indiana, 
Kansas,  Kentucky,  Missouri,  South  Dakota,  Texas,  Utah,  Vir- 
ginia, West  Virginia  and  of  other  counties  in  Pennsylvania  than 
Lehigh  and  Northampton  Counties; 


TABLE  D.  •• 

Development  of  the  Portland  Cement  Industry  in  the 
United  States  Since  1890. 


Section 

1890 

1900 

No. 
of 
w'ks 

Quantity 
(barrels) 

Percent- 
age 

No. 
of 
w'ks 

Quantity 
(barrels) 

Percent- 
age 

Lehigh  and  Northampton  Counties, 
Pa.,  and  Warren  County,  N.  J. .  . 
Ohio  

4 

5 
2 

65,000 

201,000 
22,000 

19.4 

59.9 
6.5 

8 

15 
6 
6 

15 

50 

465,832 

6,153,629 
534,215 
664,750 
663,594 

5.5 

72.6 
6.3 
7.8 
7.8 

All  other  sections  

Total  

5 

47,500 

14.2 

16 

335,500 

100.0 

8,482,020 

100.0 

Section 

1905 

1906 

No. 
of 
w'ks 

Quantity 
(barrels) 

Percent- 
age 

No. 
of 
w'ks 

Quantity 
(barrels) 

Percent- 
age 

New  York  

11 

2,111,411 

6.0 

9 

2,414,362 

5.2 

Lehigh  and  Northampton  Counties, 

Pa  

15 

13,713,910 

38.9 

17 

18,360,965 

39.5 

3 

3,654,777 

10.4 

3 

4,423,648 

9.5 

Ohio  

8 

1,312,977 

3.7 

8 

1,422,901 

3.1 

16 

2,773,283 

7.9 

14 

3,747,525 

8.1 

36 

11,680,454 

33. 1 

33 

16,094,023 

34.6 

Total  

89 

35,246,812 

100.0 

84 

46,463,424 

IQO.O 

*  Taken  from  "Mineral  Resources  of  he  United  States,"  for  1906. 


874  BUILDING  CONSTRUCTION. 

TABLE  E.* 

The  following  table  shows  the  total  production  of  puzzolan  or 
slag  cement  in  the  United  States  in  1904,  1905  and  1906,  together 
with  the  number  of  plants  in  each  State : 

« 

TABLE  E.* 


Production,  in  Barrels,  of  Slag  Cement  in  the  United  States 
IN  1 904- 1 906,  BY  States. 


1904 

1905 

1906 

State 

No. 
of 
w'ks 

Quantity 

Value 

No. 
of 
w'ks 

Quantity 

Value 

No. 
of 
w'ks 

Quantity 

Value 

Alabama.  .  .  . 

2 

187,677 

$141,402 

2 

2 

1 

1 

106,236 

$80,616 

175,942 

$168,160 

1 

Maryland..  .  . 
New  Jersey. . 

1 

1 

1 

1 

64,161 

60,478 

Ohio  

2 

115,368 

85,249 

2 



276,211 

191,998 

2 

251,121 

184,283 

Pennsylvania 

1 

1 

1 

Total.  .  . 

8 

303,045 

226,651 

9 

382,447 

272,614 

10 

481,224 

412,921 

*  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


TABLE  F* 

The  following  table  shows  the  imports  of  all  hydraulic  cements 
into  the  United  States,  by  countries,  from  1903  to  1906: 

Hydraulic  cement  is  recorded  in  the  custom-houses  in  pounds  t 

table  f.* 


Imports,  in  Barrels,  of  Hydraulic  Cements  into  the  United 
States  in  1903- 1906,  by  Countries. 


1903 

1904 

1905 

1906 

United  Kingdom  

146,994 

16,365 

33,978 

464,940 

737,576 

394,368 

335,154 

563,590 

France  

14,866 

34,912 

18,864 

64,227 

Germany  

1,377,414 

585,563 

456,325 

871,579 

Other  European  countries  

27,415 

7,538 

602 

49,770 

British  North  America  

4,421 

566 

417 

9,589 

Other  countries  

9,265 

7,091 

1,237 

182,015 

Total  

2,317,951 

1,046,403 

846,577 

2,205,710 

♦Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


APPENDIX. 


875 


when  brought  into  this  country  from  foreign  places.  Reduced  to 
barrels,  the  total  quantity  imported  in  1906  was  2,205,710,  valued 
at  $2,950,268.  The  total  quantity  withdrawn  for  consumption  in 
1906  was  2,274,677  barrels. 


TABLE  G.* 

The  following  table  is  designed  to  show  the  yearly  increase  in  the 
production  of  Portland  cement  in  the  United  States,  the  fluctua- 
tions in  natural  cement,  and  the  variations  in  imports  for  con- 
sumption of  hydraulic  cements  into  this  country  since  1901. 

The  puzzolan-cement  production,  which  is  not  included  in  this 
table,  and  which  has  been  recorded  in  government  reports  only  since 
1901,  is  as  follows:  1901,  272,689  barrels;  1902,  478,555  barrels; 
1903,  525,896  barrels;  1904,  303,045  barrels;  1905,  382,447  barrels; 
1906,  481,224  barrels. 


TABLE  G.* 

Comparison  of  Production  of  Portland  and  Natural-rock 
Cement,  in  Barrels,  in  the  Unitcd  States  with  . 
Imports  for  Consumption  of  Hydraulic 
Cement,  1901-1906. 


Total  of 

Year 

Natural 

Portland 

natural  and 

Imports 

cement 

cement 

Portland 

cement 

1901  

7,084,823 

12,711,225 

19,796,048 

922,426 

1902  

8,044,305 

17,230.644 

25.274,949 

1,963,023 

1903  

7,030,271 

22,342,973 

29.373,244 

2,251.969 

1904  

4,866,331 

26.505.881 

31,372,212 

968,410 

1905  

4,473,049 

35,246,812 

39,719,861 

896,845 

1906  

4,055,797 

46,463,424 

50,519,221 

2,274,677 

*  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


876 


BUILDING  CONSTRUCTION. 
TABLE  H.* 


In  the  following  table  it  is  impossible  to  make  comparison  between, 
domestic  Portland  cement  and  imported  Portland  cement,  for  the 
reason  that  the  figures  showing  the  .imports  or  exports  of  cement ^ 
to  or  from  this  country  are  not  divided  into  classes,  such  as  Port- 
land, natural,  or  puzzolah  cements,  but  are  received  at  the  Bureau 
of  Statistics  grouped  under  the  general  head  of  ''hydraulic 
cements."  Hence  the  table  shows  a  comparative  statement  of  the 
production  of  Portland  cement  in  the  United  States  with  the  entire 
quantity  of  hydraulic  cement  imported  into  and  consumed  in  the 
United  States,  in  1891,  1904,  1905  and  1906. 

The  apparent  decrease  in  the  percentage  of  production  to  con- 
sumption in  the  United  States  in  1906  is  explained  by  the  fact  that 
notwithstanding  the  greatly  increased  output  of  Portland  cement, 
the  demand  exceeded  the  supply.  On  the  western  coast  this  deficit 
was  most  sharply  felt,  but  it  was  a  factor  in  nearly  every  State  in 
the  Union  in  1906,  and  in  many  places  during  the  early  part  of 
the  year  building  operations  involving  the  use  of  large  quantities 
of  cement  had  to  be  suspended  pending  the  arrival  of  that  material 
from  some  other  than  the  local  market. 

The  result  of  this  shortage  was  an  unusual  and  pronounced' 

». 

TABLE  H.* 

Comparison  of  Domestic  Production  of  Portland  Cement- 
WITH  Consumption  of  Portland  and  All  Imported 
Hydraulic  Cements,  1891,  1904,  1905  and 
1906,  IN  Barrels. 


Production  of  Portland  Cement  in  the 

United  States  '. 

Imports  (entered  for  consumption) .  .  .  . 


Total  

Exports  (domestic). 


Consumption  

Percentage  of  production  of  Portland 
cement  to  consumption  in  the 
United  States  


1891 


454,813 
2,988,313 


3,443,126 


3,443,126 
13.2 


1904 


26,505,881 
968,409 


27,474,290 
774,940 


26,699.350 
99.2 


1905 


35,246,812 
896,845 


36,143,657 
897,686 


35,245,971 
100 


1906 


46,463,424 
2,274,677 


48,738,101 
583,299 


48,154.802 
96.49, 


*  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


APPEXDIX. 


877 


increusie  "in  the  quantin^  of  cement  sent  to  this  cotniTtry  from  abroad 
(dxiriiTg  tlie  latter  po^tson  of  1906. 

This  increase  is 'Wy  clearly  shown  in  the  figures  furnished  by 
Ihe  Bureaia  of  -St^fetics. 


'The  JsDStowiTTg-  table  shows  exports  of  hydraulic  cements  since 


Tke  -iailf^ihat  in  1906  the  quantity  of  cement  exported  from  this* 
(country  amotitited  to  but  little  more  than  500,000  barrels,  or  hut 
.a  trifk  over  .half  as  much  as  was  exported  during  the  preceding 
year,  marks  the  fact  that  the  supply  of  cement  in  the  United  States 
in  i^CjO  was  iiot  equal  to  the  demand. 

Tihe  total  quantity  of  hydraulic  cement  exported  from  the' 
United  "States  in  1906  was  583,299  barrels,  valued  at  $944,886;. 
(deciifedly  dess  than  the  quantity  exported  in  1904  or  1905 : 


TABLE  I.* 

ExpoTXTS  OF  Hydraulic  Cement,  1900- 1906,  in  Barrels. 


Tear 

Quantity 

Value 

^  Year 

Quantity 

Value 

1900  

100,400 
373,934 
340,821 
285,463 

$225,306 
679,296 
526,471 
433,984 

1904  

774,940 
897,686 
583,299 

SI, 104,086 
1,387,906 
944,886 

1901  

i  1905  

1902  

i  1906  

1903  

■*  Xakfiii  Jrom  "Mineral  Resources  of  the  United  States,"  for  1906. 


The  following  table  shows  the  apparent  total  consumption  in  the 
United  States  of  all  hydraulic  cements  in  1906: 

TABLE  J.* 

Total  Consumption  of  Hydraulic  Cements  in  1906,  in  Barrels. 


TABLE  I.^ 


3:900. 


TABLE  J.* 


Total  production  in  United  States.  . 
Imports  with'irawn  (or  consumption 


51,000,445 
2,274,677 


Exports 


Total 


53,275,122 
583,299 


Total  consumption. 


52,691,823 


*  Taken  from  "Mineral  Resources  of  the  United  States,",  for  1906. 


•878 


BUILDING  CONSTRUCTION. 


TABLE  K.* 

The  following  table  shows  the  value  of  the  various  kinds  of 
stone  produced  in  1905  and  1906,  by  States  and  Territories : 

TABLE  K.* 

A'alue  of  Various  Kinds  of  Stone  Produced  in  1905  and  1906, 
BY  States  and  Territories. 


1905 


■  oLutG  or  icriituiy 

Granite 

Sandstone 

Marble 

Limestone 

Total 
value 

A  1  K 

$28,107 

$532,103 

$560,210 
710 
69,393 
304,291 
2,531,928 
816.751 
1,014,064 
178,428 
5,800 
1,754,787 
33,550 
37,870 
3,541,005 
3,204.680 
9,510 
461.126 
1.003.006 
1.025,044 
2,721,223 
1,257,838 
3,263,058 
667,877 
1,331,949 
2,446,429 
274,669 
225,239 
1,500 
838,371 
1,276,781 
110,922 
5,364,222 
585,561 
1,055 
4,595,265 
195.246 
95,159 
7,956,177 
556,664 
297,284 
200,061 
992,566 
427,321 
290,728 
6,993,765 
667,050 
919,110 
842,627 
1,791,447 
59,431 

$710 

S3, 700 
90!312 
1,700,818 
73,802 

178,428 

65,558 
58,161 
685,668 
453,029 
62,618 

135 
154,818 
49,902 
289  920 
'L558 

1.000 
95  540 

5,800 
9,030 

971,207 
33,550 
1,500 

774,550 

22  265 
29!ll5 
15,421 
2,198 
9,335 
79  617 
280!579 

14  105 
3,511,890 
3,189,259 
5,512 
451,791 
923,389 
744,465 
7,428 
149,402 
65.908 
544.754 
555.401 
2,238.164 
103.123 
225,119 

Tllinois 

Tnrii  51  n  a 

1.800 

2,713,795 
2,663,329 

12,984 
367,461 
123,123 
294,640 
27,686 
45,116 
120 
1,500 

138,404 
iuo,ouu 

481,908 
180,579 
126,430 

New  Hampshire  

838,371 
834,709 

New  Jersey  

294,719 
101,522 
al,831,756 
4,483 
1,055 
1,744,472 
12,914 
1,229 
a2,487,939 

147.353 
7,200 
1,970,968 
16,500 

New  Mexico  

2,200 
795,721 

765,777 
564,578 

North  Dakota  

Ohio  

2,850,793 
163,412 
8,600 
4,499,503 
300 

18,920 
85,330 
870,848 
556,364 
297,284 

97,887 

South  Carolina  

193,408 
8,715 
123,281 
43,429 

6,653 
401,622 
171,847 
232,519 

11,095 
212,660 

52,470 
671,318 
804,081 

23,340 

Tennessee  

582,229 

132,193 
13,630 
2,571,850 
452,390 
681,730 

Utah  

1,150 
4,410,820 

Vermont  

2,0.00 
124,910 
171,309 
161,741 
33,591 

60,000 

825,625 

Wyoming  

2,500 

Total  

620,637.693 

al0,006,774 

7,129,071 

26,025,210 

63,798,748 

a  Includes  bluestone.  b  Includes  trap  and  other  igneous  rocks. 


♦  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


APPENDIX. 


8/9 


TABLE  K.  {Continued.) 

Value  of  Various  Kinds  of  Stone  Produced  in  1905  and  1906, 
BY  States  and  Territories. 

1906 


State  or  Territory 


Alabama  

Alaska  

Arizona  ^ 

Arkansas  

California  

Colorado  

Connecticut  

Delaware  

Florida  

Georgia  

Hawaii  

Idaho  

Illinois  

Indiana  

Indian  Territory. 

Iowa  

Kansas  

Kentucky  

Maine  

Maryland  

Massachusetts. . . 

Michigan  

Minnesota  

Missouri  

Montana  

Nebraska  

Nevada  

New  Hampshire. 

New  Jersey  

New  Mexico  

New  York  

North  Carolina. . 

North  Dakota. . . 

Ohio  

Oklahoma  

Oregon  

Pennsylvania.  . . 

Rhode  Island.  .  . 

South  Carolina.  . 

South  Dakota. . . 

Tennessee  

Texas  

Utah  

Vermont  

Virginia  

Washington  

West  Virginia. .  . 

Wisconsin  

Wyoming  


Total   /22,3'J6,276 


Granite 


Sandstone 


$32,042 
118,903 

1,429,207 
65,402 

1,385,369 
146.346 


r92.315 
23,346 
400 


2.560,021 
883.881 
3,790,211 


626,069 
150,009 
114,005 


818,131 
958,110 


027,483 
778,847 


18,847 
58,961 
1,043,140 
622,812 
247,998 


$40,467 


33,149 
55,703 
642,166 
286,544 


11,969 
19,125 
30,740 
615 
5.601 
42.809 
125.123 


9,533 
260.721 
65,395 
285,633 
20,951 
37,462 
6,899 


215,142 
42,574 
del  ,905,892 
3,531 
44 

1,426,645 
40,246 
25,950 
d2,724,874 


168,061 
4,948 
2.941,724 
340.900 
459,975 


798,213 
600 


145,966 
14,136 

111,533 
37,529 


5.100 
169.500 
113,369 
181,986 
24,715 


9,169,337 


Marble 


$85,000 

(a) 


16,900 
103,048 


919.356 


176,495 
271,934 


5,000 


500 
557,954 


171.632 


635,821 


1,400 
,576,913 


59,985 
'  1,666 


7,582,938 


Limestone 


$579,344 


40 
48,844 
80,205 
373,158 
1.171 


1,450 
16,042 


12,600 
2,942,331 
3,725,565 
44,622 
493,815 
849,203 
795,408 
2,000 
170,046 
10,750 
656.269 
632.115 
1,988,334 
141,082 
276,381 


221,141 
125,493 
2,204,724 
30,583 


3,025,038 
127,361 
7,480 
4,865,130 
678 
10,400 


481,952 
239,125 
248,868 
7,829 
260,343 

49,192 
628,602 
891,746 

53,783 


27,320.243 


Total 
value 


$704,811 
(a) 

65,231 
240,350' 
2,254,626 
725.104 
1,386,540' 
146,346 
1,450' 
1.727.713 
23.346- 
24,969 
2,961,456 
3,756,305 
45,237 
499.416 
892,012; 
920,531 
2,562,021 
1,239,95S 
4,333,61S 
721,664 
1.543,817 
2,159,294 
292,549 
283,28a 
5,000 
818,131 
1,394,393 
168,567 
5,596,05a 
812,961 
44 

4,451,68a 
186,454 
92,391 

8,804,776 
623,490 
258,39S 
145,966 

1,131,909 
518.719 
292,745 

7,526,466 
606.34a 
738.652 
741.971 

1,871,945 
80,09S 


,378,794 


a  Included  with  Washington. 
h  Included  with  New  York. 
c  Included  in  hmestone. 
d  Includes  bluestone. 

e  Includes  a  small  output  for  Connecticut. 
/  Includes  trap  rock  and  other  igneous  rocks 


88o  BUILDIXG   COX STRUCTION. 


TABLE  L* 

The  following  tabic  shows  the  rank  of  the  States  and  Territories 
in  1905  and  1906,  according  to  value  of  production  of  stone,  and 
the  percentage  of  the  total  stone  produced  by  each  State  or  Terri- 
tory :  TABLE  L.* 

Rank  of  States  and  Territories  in  1905  and  1906,  According 
TO  Value  of  Production  of  Stone,  and  Percentage  of 
Total  Stone  Produced  by  Each  State  and  Territos^y, 


1905 


1 

2 
3 
4 
5 
6 

8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 
48 
49 


State  or  Territory 


Pennsylvania. ,  .  , 

Vermont  , 

New  York  , 

Ohio  

Illinois  

Massachusetts  .  . 

Indiana  

Maine  

California  

Missouri  

Wisconsin  

Georgia  

Minnesota.  ...... 

New  Jersey  

Maryland  

Kentucky  

Connecticut .... 

Kansas  

Tennessee  

Washington .... 
West  Virginia.  .  . 
New  Hampshire. 

Colorado  

Michigan  

Virginia  

North  Carolina.. 

Alabama  

Rhode  Island.  . .  . 

Iowa  , 

Texas  

Arkpnsas  

South  Carolina..  . 

Utah  

Montana  

Nebraska  

South  Dakota .  . 

Oklahoma  

Delaware  

New  .Mexico  

Oregon  

Arizona  

Wyoming  

Idaho  

Hawaii  

Indian  Territory. 

Florida  

Nevada  

North  Dakota  .  .  . 
Alaska  


Total. 


Total 
value 


$7,956,177 
6,993,765 
5,364,222 
4,595,265 
3,541,005 
3,263,058 
3,204,680 
2,721,223 
2,531,928 
2,446,429 
1,791,447 
1,754,787 
1,331,949 
1,276,781 
1,257,838 
1,025,044 
1,014,064 
1,003,006 
992,566 
919,110 
842,627 
838,371 
816,751 
667,877 
667,050 
585,561 
560,210 
556,664 
461,126 
427,321 
304,291 
297,284 
290,728 
274,669 
225,239 
200,061 
195,246 
178,428 
110,922 
95,159 
69,393 
59,431 
37,870 
33.550 
9,510 
5,800 
1,500 
1,055 
710 


Per- 
centage 
of  total 


12.47 
10.96 
8.41 
7.20 
5.55 
5.11 
5.02 
4.27 
3.97 
3.83 
2.81 
2.75 
2.09 
2.00 
1.97 
1.61 
1.59 
1.57 
1.56 
1.44 
1.32 
1.31 
1.28 
1.05 
1.05 
.92 
.88 
.87 
.72 
.67 
.48 
.47 
.46 
.43 
.35 
.31 
.31 
.28 
.17 
.15 
.11 


.23 


63,798,748  100.00 


1906, 


State  or  Territory 


Pennsylvania..  .  . 

Vermont  

New  Yorka  

Ohio  

Massachusetts. . . 

Indiana  

IHinois  

Maine  

California  

Missouri  

Wisconsin  

Georgia  

Minnesota  

New  Jersey  

Connecticut  

Maryland  

Tennessee  

Kentucky  

Kansas  

New  Hampshire. 
North  Carolina.  . 
West  Virginia.  .  . 
Washington6.  .  .  . 

Colorado  

Michigan  

Alabama  

Rhode  Island  .  .  . 

Virginia   

Texas  

Iowa  

Utah  

Montana  

Nebraska  

South  Carolina.  . 

Arkansas  

Oklahoma  

New  Mexico  

Delaware  

South  Dakota.  .  . 

Oregon  

Wyoming  

Arizona  

Indian  Territory. 

Idaho  

Hawaii  

Nevada  

Florida  

North  Dakota.  . . 


Total 


Total 
value 


$8,804,776 
7,526,466 
5,596,053 
4,451,683 
4,333,616 
3,756,305 
2,961,456 
2,562,021 
2,254,626 
2,159,294 
1,871,945 
1,727,713 
1,543,817 
1,394,393 
1,386.540 
1,239,955 
1,131,909 
920,531 
892,012 
818.131 
812,961 
741,971 
738,652 
725,104 
721,664 
704,811 
623.490 
606.343 
518.719 
499,416 
292,745 
292,549 
283,280 
258,398 
240,350 
186,454 
168.567 
146.346 
145.966 
92,391 
80,098 
65,231 
45,237 
24,969 
23,346 
5,000 
1,450 
44 


66,378,794 


Per- 
centage 
of  total 


13.27 
11.34 
8.43 
6.71 
6.53 
5.66 


46 
86 
40 
25 
82 
60 
33 
10 
09 
1.87 
1.71 
1.39 
1.34 
1.23 
1.23 
1.12 
1.11 
1.09 
1.09 
1.06 
.94 
.91 
.78 
.75 
.44 
.44 
.43 
.39 
.36 
.28 
.25 
.22 
.22 
.13 
.12 
.10 


15 


100.00 


a  Includes  a  small  output  of  sandstone  from  Connecticut:       b  Includes  Alaska  marble. 


*  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


0 


APPENDIX. 


The  four  following  tables,  M,  N,  O  and  P,  with  the  addenda 
relating  to  the  properties  and  chemical  composition  of  building 
stones  and  to  stone  buildings,  have  been  compiled  by  the  author 
from  various  sources  (principally  from  several  volumes  of  Stone 
and  from  Merrill's  "Stones  for  Building  and  Decoration"),  and  are 
'believed  to  be  reliable: 

TABLE  M.§ 

Showing  the  Weight,   Crushing  Strength  and  Ratio  of 
ABSofeJ>TioN  OF  Various  Building  Stones. 


Kind  of  Stone. 


<vr«nite  (Biotite). 


^Qhranite  (Hornblende). 


Granite  (Biotite). 


'Granite  (Hornblende). 


Granite  (Gabbro). 
<;ranite  (Biotite), . 


Limestone  (Dolomite). 
Limestone  (Oolitic). . . 


Limestone  (Dolomite). 


Locality. 


Vinalhaven,  Me. . 
Dix  Island,  Me. . 
Hurricane  Island, 


Me. 


Fox  Island,  Me. 
Keene,  N.  H... 
Cape  Ann,  Mass. 


Rockport,  Mass. 
Quincy,  Mass. . . 


Milford,  Conn. 
Westerly,  R.  I. 


Huron  Island,  Mich. 


East  Saint  Cloud,  Minn, 


Saint  Cloud,  Minn.. 

Duluth,  Minn  

Tarrytown,  N.  Y..., 
Staten  Island,  N.  Y. 

Gunnison,  Colo  


Platte  Canon,  Colo. 

Joliet,  111  

Lemont,  111  

Quincy,  111  

Bedfcrd,  Ind  


Salem,  Ind. 
Stillwater,  Minn. 


(buff)  .... 


^  4, 


c 

o 

rength  per 
uare  inch. 

/^eight  per 
ubic  foot. 

Ratio  of 
bsorption. , 

C/2 

< 

Bed 

15.698 

163 

— — 
.  •  ■  • 

15,000* 

166.5 

. .  •  • 

Bed 

14.425* 

166.9 

. . .  • 

Edge 

14,937* 

166.9 

•  •  •  • 

14,875* 

164. 1 

...» 

Bed 

10,375 

166 

Bed 

12,423* 
19,500* 
16,300  I 
19,750  J 

Bed 

Bed 
Edge 

163.2 

I7,750t 

166.2 

•  •  »  • 

i4,75ot 

168.7 

22,610 
17.500 

165.6 

Edge 

14.937* 

166.9 

Bed 

18,125 

164.4 

Edge 

14,425 

163.7 

Bed 

28,000  ) 

168.2 

Edge 

26,250  ) 

Bed 
Edge 

16,000  } 
18,500  f 

168.2 

Bed 

17,631 

175 

Bed 

i8,25of 

162.2 

Bed 

22,250f 

178.8 

Bed 

12,976  I 

169.4 

Edge 

15,594  ) 

Bed 

14,585  / 

163.8 

Edge 

14.634  ) 

Bed 

14,775* 

160 

Bed 

12,000* 

165.3 

1 

Bed 

9,687* 

160.6 

6,500 

147 

10,125 

152.4 

i4,ooo:|: 
8.625 

Bed 
Edge 

144-3 

25,000  I 
25,000  1 

172.6 

irix 

Bed 
Edge 

10,750  [ 
12,750  [ 

160.4 

*  Burst  suddenly.  f  Gracked  before  bursting. 

t  Tests  made  at  U.  S.  Arsenal,  Watertown,  Mass.  §  See  also  Addenda  to  this  Table. 
Consult  also  Art.  229,  Chap.  V.,  for  a  list  of  some  recent  publications  on  building 
atones,  in  which  the  various  properties  of  other  stones  are  given. 


882 


BUILDING  CONSTRUCTION, 


TABLE  M  (Continued.) 


Kind  of  Stone. 


Limestone  (Dolomite). . . 
Limestone  (Magnesian).. 


Marble  (Dolomite). 


Red  Wing,  Minn   . 

Glens  Falls,  N.  Y  

Lake  Champlain,  N.  Y. 

Lee,  Mass  

C  intre  Rutland,  Vt  

Dorset.  Vt  

"Cherokee,"  Georgia... 


Marble  (Pink).., 
Marble  (White), 


Marble  (Dark  Pink).. .  . 
Sandstone  (Brownstone) 


Sandstone  (Con.) 

Brown  (soft)., 
"  (hard), 
(Kibbe)  , 


(lilac  color). . 
(light)  


Locality. 


"Creole,"  Georgia. 


"  Etowah,"  Georgia. .  . 

"Kennesaw,"  Georgia. 
East  Tennessee  


Portland,  Conn. 


Cromwell,  Conn  

East  Longmeadow,  Mass 

Potsdam,  N.  Y  

Medina,  N.  Y  

North  Amherst,  Ohio . . . 


Berea,  Ohio. 


(hard,  red), . 
(hard,  gray). 

(light  red). . . 


Cleveland,  Ohio. . . 
Hummelstown,  Pa. 
Fond  du  Lac,  Wis. 
Saint  Vrains,  Colo. 
Fort  Collins,  Colo. 

Stout,  Colo  

Manitou,  Colo  


SLATE. 


Locality. 

Modulus  of 
Rupture. 

Weight  per 
cubic  foot. 

Porosity. 

Corrodibility. 

7,150  lbs. 

173.2 

0.238 

0.547 

9,810  " 

173-5 

0.145 

0.446 

11,260  " 

180.4 

0.224 

0.226 

*  Burst  suddenly.  f  Cracked  before  bursting. 

t  Tests  made  at  U.  S.  Arsenal,  Watertown,  Mass. 


'APPENDIX. 


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CO  (M  (N  C^l  (M  (M 


CD-* 


COIM 
X  X 


CO 
X  X 

rHCO 


X  x' 

Olio 
■03 


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CO 


o  fto 


=  2 


c  c  c  c  . 
aj  O)  s3  g  . 


OO 


ci2 

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^  i 


3~ 

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11°  d 

—  3  w  a> 

om 

2«i.i 


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-2  O 


c  ft 


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!/5 


'884  'BUILDING  CONSTRUCTION. 

TABLE  N.* 

Showing  the  Chemical  Composition  of  Various  Building 

STONES.f 

granites. 


Description. 


Light  

Dark  

Hornblende. 


Diabose 
'  Gabbro . 


Locality. 

ci 

u 

c 
S 

B 

tash 
Sod 

3 
< 

73-47 

15-07 

1. 15 

4-48 

5.97 

69 -35 

18.83 

2.00 

5.94 

3.78 

East  Saint  Cloud,  Minn. 

65.12 

16.96 

4.69 

4-77 

5-25 

74-43 

12.68 

3.82 

1.28 

3.88 

50.43 

23.83 

17.63 

4-79 

2.40 

48.51 

13-79 

19-34 

8-34 

T.86 

SANDSTONES. 


Description. 


Maynard  (red)  

Worcester  (red). . . . 

Kibbe  quartz  

Brownstone  

Sandstone  

Portage  Entry  (red) 

'Quartzite  

Buff  

Berea  

Euclid  Bluestone. . 

Columbia  

Red  

Elyria  

'Sandstone  


Locality. 


E.  Longmeadow,  Mass. 

Portland,  Conn  

Stony  Point,  Mich  

Lake  Superior,  Mich. . . 

Pipestone,  Minn  

Amherst,  Ohio  

Berea,  Ohio  

Euclid  County,  Ohio. . . 

Columbia,  Ohio  

Laurel  Run,  Pa  

Grafton,  Ohio  

Fond  du  Lac,  Minn.  .  . 

Flagstaff,  Arizona  

Dorchester,  N.  Brunsw'k 


Silica. 

Alumina. 

Iron 
Oxides. 

Lime. 

Water 
and  Loss. 

79-38 

8.75 

2.43 

2.57 

2.79 

88.89 

5.95 

1.79 

.27 

1.83 

81.38 

9-44 

3-54 

.76 

4-49 

69.94 

13-15 

2.48 

3-09 

1 ,01 

70.  II 

13-49 

4-85 

2.39 

7-37t 

84-57 

5.90 

6.48 

1 .92 

94-73 

0. 36 

2.64 

0.69 

.83 

84.52 

12.33 

2.12 

0.31 

2.31 

97.00 

1. 00 

1.15 

.21 

96.90 

1.68 

.55 

•32 

95-00 

2.  50 

1. 00 

1.50 

96.50 

2.00 

94.00 

1 .90 

1. 10 

1 .92 

87.66 

1.72 

3-52 

.17 

2.03 

78.24 

10.88 

3-83 

•95 

79.19 

3 

75 

7.76 

3.26 

82.52 

7.07 

3-55 

1.83 

3-61 

t  Some  minor  elements  occurring  in 
durability  of  the  stone  are  omitted. 

*  See  also  Art.  229,  Chap.  V.,  for  a  list 
in  which  the  chemical  composition  of  other 


very   smalf  quantities   and   not   affecting  the 

I  Potash  and  soda, 
of  some  recent  publications  on  building  stones, 
stones  are  given. 


APPENDIX 


885 


TABLE  N  {Continued.) 
LIMESTONES  OTHER  THAN  MARBLES. 


Description. 


Dolomite  

Oolitic  

"  (buff) .*.*.*.'!.* 

"  (blue)  

Oolitic  

-Dplomite  

<« 

Ximestone  

-Dolomite  

Limestone  (Caen). . 

(Oolitic) 


Locality. 


Lemont,  111. 


Bedford.  Ind. 


Spencer,  Ind  

Bowling  Green,  Ky. 
Minneapolis,  Minn  . 


Kasota,  Minn  

Stillwater,  Minn. . . 
Frontenac,  Minn.. 

Dayton,  Ohio  

Springfield,  Ohio.. 
Aubigney,  France, 
Portland,  England. 


Carbonate 
of  Lime. 

Carbonate 
of  Mag- 
nesia. 

Oxides  of 
Iron. 

Oxide  of 
Aluminum. 

45.80 

2.30 

7.00 

96,60 

0.13 

0. 

98 

97.26 

0.37 

0.49 

98.20 

0.39 

0.39 

97.26 

0.37 

0.49 

96.80 

0.  II 

0.91 

95.31 

1. 12 

0.39 

54-53 

36 

0.90 

3. 16 

41.88 

24-55 

4-03 

75.48 

6,81 

1 , 70 

49.16 

57.53 

1 .09 

50,22 

37-39 

0.78 

0.64 

54-78 

42.53 

0.36 

0.31 

92,40 

1 . 10 

0.58 

54-70 

44-93 

0.20 

97.60 

95.16 

1.20 

0.50 

15.90 

0.50 
1.69 
0.63 
1.69 
0.70 
1,42 
16.22 
29-93 
14-45 
13.06 

8-54 
2.93 
1.70 
o.  10 
1.70 
1.20 


(U  o 

6.90 

0.96 
o.  19 


0.92 
1,76 
0.375 


1 .60 


1.08 


94 


MARBLES. 


Description. 


Dolomite  , 

(white)  

«« 

"  (white).!.*!.*!!!! 

Limestone  (white)  

•*  (greenish)  

**  (white)  

"  (bluish  gray). . 
"        (light  colored) 

Georgia  Marble  Co  

Southern  Marble  Co  

Carrara  (white)  


I^ocality. 


Hastings,  N.  Y. . . 
Sing  Sing,  N.  Y. . . 
Tuckahoe,  N.  Y. , . 
Pleasantville,  N.  Y 

Lee,  Mass  

Rutland,  Vt  

West  Rutland,  Vt. 
Proctor,  Vt  

East  Tennessee. . . 
Georgia  

Italy.  


Carbonate 
of  Lime. 

Carbonate 
of  Mag- 
nesia. 

Oxides  of 
Iron  and 
Aluminum. 

Insoluble 
Residue. 

52.82 

45.78 

53.24 

45-89 

61.75 

38-25 

54.62 

45-04 

0.23 

54.62 

43-93 

.365 

97-73 

•59 

i!68 

85-45 

14-55 

98,00 

0.57 

98.37 

0.79 

0.005 

0.63 

96.30 

3.06 

0.63 

98.78 

0.67 

o!26 

.08 

97-32 

1 .60 

.26 

98.96 

0.13 

.22 

98-52 

0.88 

99.24 

0.28 

98.76 

0.9 

i!o8 

0.16 

886 


BUILDING  CONSTRUCTION. 


TABLE  N  (Continued.) 
ONYX  MARBLES. 


Source. 


Hacienda  del  Carmen,  Mexico  

Mayer's  Station,  Arizona  

Cave  Creek,  Arizona  

Suisin  City,  California  

Sulphur  Creek,  "   

San  Luis  Obispo,  California  

Rio  Puerco,  Valencia  County,  New 

Mexico  

New  Pedrara,  Lower  California, . . . 

<<  <• 

<(  It 

<«  «< 
Near  Lehi,  Utah  


Color. 


Light  green  

Red  brown  

Light  green  

Dark  amber  

White  

Light  green  

Faintly  green  

White,  rose  tinted. . 

White  

Faintly  green  

Yellow  


Weight  per 
cubic  foot. 

Carbonate 
of  Lime. 

Carbonate 
of  Mag- 
1  nesia. 

Carbonate 
1   of  Iron. 

171.87 

89.36 

3.00 

5.24 

171.87 

93.93 

0.  56 

5.50 

166.87 

93.82 

0.53 

4.06 

171.87 

93-48 

1.07 

5.19 

170.62 

95-48 

2.20 

167.5 

170 

93*68 

1-43 

3-93 

179-37 

174-37 

90. 16 

i*.66 

6.97 

173 

93-48 

1.68 

4.19 

174 

96.86 

0.24 

2.^9 

174-37 

91.09 

0.64 

7-49 

170 

97-61 

0.23 

.... 

SLATES. 


Source. 


Rutland  County,  Vt.  (sea  green)  , 

"  (unfading  green), 

(purple)  

Granville,  N.  Y.  (red)  

Old  Bangor,  Penn.  (dark)  

Albion,  Penn.  (dark)  *. . 

Peach  Bottom  Region,  Penn.  (dark). . . 


Silica.* 

Alumina.* 

Protoxide 
of  Iron.* 

Peroxide 
of  Iron.* 

Magnesia. 

Alkalies. 

65.02 

16.02 

5-44 

2.99 

2.00 

4. 16 

64.71 

7.84 

5-44 

7-23 

1 .63 

6.92 

62.37 

13.40 

4.21 

7.66 

0.90 

7.20 

73-97 

5.16 

1-74 

10. 17 

1.43 

3.92 

56.97 

26.05 

2.6g 

2.31 

55.18 

25 . 57I  carbon 

2.10 

4.00 

58.37 

21.98 

10.66 

0.93 

1.20 

1.93 

*  These  are  the  valuable  constituents.  "Peroxide  of  iron  is  probably  the  coloring 
matter." 


APPENDIX. 


887 


TABLE  O.* 

List  of  Important  Stone  Buildings  in  the  United  States, 
granite  buildings. t 


Locality  of  Quarries. 


Dix  Island,  Me. 
Hallowell,  Me.. 


Cape  Ann,  Mass, 
Milford,  Mass... 
Quincy,  Mass. . . . 


Concord,  N.  H  

Gunnison,  Colo  

Little  Cottonwood  Canon, 
Utah  


Name  of  Building. 


Post  Office  

(New)  Post  Office  

State  Capitol  

State  Capitol  

Equitable  Insurance  Co.  Building  

Post  Office  

City  Hall  

U.  S.  Custom  Houf=e  

Bunker  Hill  Monument  

Post  Office  

Astor  House  

Philadelphia  National  Bank  

Presbyterian  Church  

U.  S.  Custom  House  

U.  S.  Custom  House. . ,  

Congressional  Library  

State  Capitol  

State  Capitol  

Mormon  Assembly  House  and  Temple. 


City. 


New  York  City. 
Philadelphia,  Pa. 
Albany,  N.  Y. 
Augusta,  Me. 
Boston,  Mass. 

Albany,  N.  Y. 
Boston,  Mass. 
Charlestown,  Mass. 
Providence,  R.  I. 
New  York  City. 
Philadelphia. 
Savannah,  Ga. 
Mobile,  Ala. 
New  Orleans,  La. 
Washington,  D.  C. 
Concord,  N.  H. 
Denver,  Colo. 

Salt  Lake  City,  Utah. 


limestone.  BUILDINGS. J 


Locality  of  Quarries. 


Name  of  Building. 


City. 


Lockport,  N.  Y  

Bedford,  Ind  

(( 
it 
(( 
{( 

({ 
** 

I 

(( 

*' 

Lemont,  111  

(( 

St.  Paul,  Minn  

Kaosta,  Minn  

Bowling  Green,  Ky 


Lenox  Library  

Algonquin  Cliib  Building  

Residence  of  Mr.  Robert  Goelet  

Manhattan  Life  Insurance  Building  

Mail  and  Express  Building  

American  Fine  Arts  Society  Building  

Residences  of  Cornelius  Vanderbilt  and 

W.  K.  Vanderbilt  

Manufacturers'  Club  Building  

Tioga  Baptist  Church  

State  Capitol  

Auditorium  Building  

Union  Station  

Cotton  Exchange  Building  

Biltmore  

St.  Paul  Universalist  Church  

Central  Music  Hall  

Catholic  Cathedral  

Post  Office  

U.  S.  Custom  House  


New  York  City. 
Boston,  Mass. 
Newport,  R.  I, 
New  York  City. 


"  (Fifth 

Avenue). 
Philadelphia,  Pa. 
<( 

Indianapolis,  Ind. 
Chicago,  IlL 
St.  Louis,  Mo. 
New  Orleans,  La. 
Biltmore,  N.  C  . 
Chicago,  111. 
(( 

St.  Paul,  Minn. 
Nashville,  Tenn. 


*  See  also  Addenda  to  this  Table,  This  table  and  the  addenda  are  given  as  a  guide 
to  architects  in  judging  of  the  appearance  and  weathering  properties  of  different  stones. 

Some  of  these  stones  are  used  in  a  great  -many  other  buildings  in  the  cities  men- 
tioned, the  idea  of  the  author  being  to  give  only  one  or  two  examples  in  each  city. 

t  See  also  Chap.  V.,  Art.  230,  for  new  classified  lists  of  buildings  recently  erected, 
in  which  various  kinds  of  granite  are  used, 

X  See  also  Chap.  V.,  Art.  232,  for  new  lists. 


888 


BUILDING  CONSTRUCTION. 


TABLE  O  {Coniinued.) 
MARBLE  BUILDINGS." 


Locality  of  Quarries. 


Rutland,  Vt  

Lee,  Mass  

(( 

Tuckahoe,  N.  Y  

(( 

Montgomery  County,  Pa 
East  Tennessee  

i( 

(( 

<( 

Georgia  


Name  of  Building. 


(Old)  Parker  House,  on  School  Street 

St.  Patrick's  Cathedral  (in  part)  

New  City  Buildings  

Washington  Monument  (in  part)  

U.  S.  Capitol  Extension  

New  York  Life  Insurance  Building. . . 

Hotel  Vendome  (new  part)  

Girard  College  

Blackstone  Memorial  Library  

U.  S.  Custom  House  and  Post  Office.. 
U.  S.  Custom  House  and  Post  Office.. 
U.  S.  Custom  House  and  Post  Office.. 

Trimmings,  Ames  Building  

St.  John's  Episcopal  Church  

Grand  Opera  House  

U.  S.  Custom  House  and  Post  Office.. 


City. 


Boston,  Mass. 
New  York  City. 
Philadelphia,  Pa. 
Washington,  D.  C. 

Boston,  Mass.  • 

a 

Philadelphia,  Pa. 
Branford,  Conn. 
Knoxville,  Tenn. 
Memphis,  Tenn. 
Chattanooga,  Tenn, 
Boston,  Mass. 
Knoxville,  Tenn. 
Atlanta,  Ga. 
Jacksonville,  Fla. 


SANDSTONE   BUILDINGS. f 


Locality  of  Quarries. 


Name  of  Building. 


City, 


Longmeadow,  Mass.  (red 
stone)  

Longmeadow,  Mass.  (red 
stone)  

Portland,  Conn. 

(brownstone) . . 


Potsdam,  N.  Y.  (red  stone) 


Ohio  Sandstone  (buff  stone) 
((  i( 

Portage  Entry,  Mich,  (red 
stone)  

Fond  du  Lac,  Minn,  (red- 
dish brown  stone)  

Kettle  River,  Minn  

Fort  Collins,  Colo,  (dark 
red  stone)  

Fort  Collins,  Colo,  (dark 
red  stone)  

Fort  Collins,  Colo,  (dark 
red  stone)  

Manitou,  Colo,  (red  stone). 


Trimmings,  Trinity  Church. 
Union  League  Club  House. , 


Technology  (original)  Building  

Alumni  Hall,  Jjibrary  and  Art  School, 

Yale  College  

Residences  of  Wm.  H.  Vanderbilt  and 

Messrs.  Twombly  and  Webb  : . . 

Astor  Library.  

Academy  of  Design  (Montague  Street)  

Music  Hall  

Union  League  Club  Building  

Residence  of  Geo.  H.  Pullman  

Savings  Bank  of  Baltimore  

Parliament  Buildings  

Columbia  College  

All  Saints  Cathedral   

Palmer  House  

State  Capitol  


State  Mining  School  Buildings. 


Westminster  Presbyterian  Church. 
Board  of  Trade  Building  


Grace  Methodist  Church. 


Union  Pacific  Depot. 


American  Exchange  Bank. 
Boston  Building  


Boston,  Mass. 

Chicago,  111. 

Boston,  Mass. 

Hartford,  Conn. 

New  York  City  (Filth 

Avenue). 
New  York  City. 
Brooklyn,  N.  Y. 
Buffalo,  N.  Y. 
Philadelphia,  Pa 
Chicago,  111. 
Baltimore,  Md. 
Ottawa,  Ont. 
New  York  City, 
Albany,  N.  Y. 
Chicago,  111. 
Lansing,  Mich. 

Houghton,  Mich. 

Minneapolis,  Minn. 
West  Superior,  Wis, 

Denver,  Colo. 

Cheyenne,  Wy. 

Kansas  City,  Mo. 
Denver,  Colo 


*  See  also  Chap.  V.,  Art.  235,  for  new  classified  lists  of  buildings  recently  erected,, 
in  which  various  kinds  of  marble  are  used. 

t  See  also  Chap.  V.,  Art.  239,  for  new  lists. 


APPENDIX, 


889, 


addenda*  for  table  o.. 

List  of  Some  of  the  More  Important  Stone  Structures  of  the 

United  States. 


locality 


STRUCTURE 


material 


Allegheny,  Pa. 
Ashland,  Wis. 


Astoria,  Ore  

Baltimore,  Md  .  .  . 

Boston,  Mass  

.  .  .  .do  

.  .  .  .do  

....  do  

Bridgeport,  Conn. 
Brooklyn,  N.  Y... 

Camden,  N.  J  

Charleston,  S.  C. 


Chicago,  111  

Cincinnati,  Ohio. 
Columbus,  Ohio. 
Dayton,  Ohio.  .  . 
Des  Moines,  la. . 


Detroit,  Mich .  .  .  , 
Duluth,  Minn.  .  .  . 
Evansville,  Ind.. . 
Fort  Wayne,  Ind. 
Frankfort,  Ky.  .  .  . 
Jacksonville,  Fla. 
Kansas  City,  Mo. 

Lafayette,  Ind.  .  . 
Little  Rock,  Ark . 

Lowell,  Mass  

Madison,  Ind  


Milwaukee,  Wis. 


Minneapolis,  Minn. 
New  Albany,  Ind. , 

Newark,  N.  J  

Newhaven,  Conn.  . 
New  York  City. . . . 
... .do  


Post-ofRce . 
.  .  .do  


Custom-house  

Court-house  and  P.  O.  . 

Tremont  building  

Chamber  of  Commerce  . 
Exchange  Building.  .  .  . 
S.  Union  R.  R.  Station. 

Post-office  

.  .  .do  

Custom-house  and  P.  O. 
Custom-house  


Newberry  Library  

Chamber  of  Commerce. 
Court-house  and  P.  O.. 

Post-office  

Court-house  and  P.  O.. 


.do. 
.do. 
.do. 

.do. 
.do. 
.do. 
.do. 


Post-office  

Court-house  and  P.  O. 

Post-office  

...  do  


Court-house,  Post-office,  and 

Custom-house  

Post-office  

Court-house  and  P.  O  

Custom-house  and  P.  O  

Osborn  Memorial  Hall  

Court-house  and  P.  O  

Library,  Columbia  U  


Granite,  HoUowell,  Me  

Sandstone,    Prentice  Quarry, 

Houghton,  Wis  

Sandstone,  near  Astoria  

Granite,  Cape  Ann,  Mass  

Granite,  Milford,  Mass  

. . . .do.  

.  .  .  .do.  .  .Stony  Creek,  Conn  

.  . . .do  

Sandstone,  Middlesex  Co.,  Conn.. 

Granite,  Vinalhaven,  Me  

Marble,  Proctor,  Vt  

Marble,    Hastings,    N.    Y.,  and 

Tuckahoe,  N.  Y  

Granite,  Stony  Creek,  Conn  

Granite,  Milford,  Mass  

Sandstone,  Berea,  Ohio  

.  .  .  .do  

Limestone,     Keokuk,     111.,  and 

Joliet,  111  

Limestone,  Bedford,  Ind  

,  .  .  .do  

. . .do  

Sandstone,  Sand  Point,  Mich  

Limestone,  Bedford,  Ind  

Georgia  Marble  

Granite,  South  Park,  Colo.,  and 

Llano  Co.,  Tex  

Berea  Sandstone  

...  do  

Granite,  Deer  Island,  Me  

Sandstone,    Portage,   Mich.,  and 

Limestone,  Bedford,  Ind  

Granite,  Frankfort,  Me  

Sandstone,  Berea,  Ohio  

. . .do  

Sandstone,  Belleville,  N.  J  

Granite,  Stony  Creek,  Conn  

Granite,  Dix  Island,  Me  

Granite,' Stony  Creek,  Conn.,  and 
Milford  Mass  


*  Taken  by  permission  from  1903  edition  of  "Stones  for  Building  and  Decoration,"  by. 
George  P.  Merrill. 


.890  BUILDING  CONSTRUCTION. 


ADDENDA    FOR  TABLE  O. 
{Continued.) 

Important"  Stone  Structures  of  the  United  States. 


LOCALITY 


Pensacola  

Peoria,  111  

Philadelphia,  Pa. 
Pittsburg,  Pa.. . . 

....  do  

....do  

Portland,  Me  


Portland,  Ore  

Port  Townsend,  Wash. 


Providence,  R.  I  

.  .  .  .do  

Quincy,  111  

Raleigh,  N.  C  

Rochester;  N.  Y  

Rockford,  111  

San  Francisco,  Cal. ...... 

San  Jose,  Cal  

Savannah,  Ga  

Scranton,  Pa  

Sioux  City,  la  

Sioux  Falls,  S.  D  

Springfield,  111  

Springfield,  Mass  

St.  Augustine,  Fla  

St.  Louis,  Mo  

Stanford  University,  Cal. 

Trenton,  N.  J  

Washington,  D.  C  

.  .  .  .do  

.  .  . .do  

Wichita,  Kansas  

Wilmington,  N.  C  

Worcester,  Mass  


STRUCTURE 


Court-house  and  P.  O  

.  .  .  .do  

Custom-house  

Court-house  and  P.  O  

Allegheny  Co.,  Court-house. 

Pittsburg  Bank  

Custom-house  


Custom-house  and  P.  O. 
.  .  .do  


State-house  

Custom-house  and  P.  O..  . 

Court-house  and  P.  O  

.  .  .do  

...  do  

Post-office  

.  .  .do  , 

.  . .do  

Court-house  and  P.  O  

Post-office  

Court-house  and  P.  O  

.  .  .do  

.  .  .do  

Post-office  

Court-house  and  P.  O  

.  .  .do  

University  buildings  

Custom-house  and  P.  O. .  . 

Post-office  

New  Corcoran  Art  Gallery 

New  Public  Library  

Court-house  and  P.  O  , 

Custom-house  and  P.  O..  . 
City  Hall  


MATERIAL 


Limestone,  Bowling  Green,  Ky. .  . 

Sandstone,  Amherst,  O  

Marble,  Montgomery  Co..  Pa  

Granite,  E.  Blue  Hill,  Me  

Granite,  Milford  Mass  

Granite,  Troy,  N.  H  

Granite,  Concord,  N.  H.,  and  Hol- 
lowell,  Me  

Sandstone,  near  Astoria  

Sandstone,  BeUingham  Bay,  Wash- 
ington  

Marble,  Pickens  Co.,  Ga  

Granite,  Quincy,  Mass  

Oohtic  Limestone,  Bedford,  Ind.. 

Granite,  Goldsboro,  N.  C  

Sandstone,  Portland,  Conn  

Red  Sandstone,  Portage,  Mich..  .  . 

Granite,  Rocklin,  Cal  

Sandstone,  San  Jose,  Cal  

Cherokee  Marble,  Pickens  Co.,  Ga. 

Granite,  Hurricane  Island,  Me..  .  . 

Limestone.  Bedford,  Ind  

Quartzite,  East  Sioux  Falls,  S.  D. 

Limestone,  Nauvoo,  111  

Sandstone,  Longmeadow,  Mass. .  . 

Coquina,  St.  Augustine,  Fla  

Granite,  Hurricane  Island,  Me..  .  . 

Sandstone,  Santa  Clara  Co.,  Cal..  . 

Sandstone,  Amherst,  O  

Granite,  Vinalhaven,  Me  

Marble,  Pickens  Co.,  Ga  

Marble,  Proctor,  Vt  

Limestone,  Bedford,  Ind  

Sandstone,  Sanford,  N.  C  

Granite,  Milford,  Mass  


4 


APPENDIX. 


TABLE  P. 

The  Effect  of  Heat  on  Various  Building  Stones.* 


Kind. 


Light  colored  granite  

Red  granite  

Carter's  Quarry  granite. . . 

Syenite  

Oomraon  granite  

'Old  Dominion  Quarry  gran 

ite  

Light  colored  granite  

Sandstone  

Sandstone  

Sandstone  

Potsdam  sandstone  

Berea  sandstone  

Limestone  

Limestone  

Cincinnati  limestone.    . . . 

Potts'  blue  limestone  , 

Dolomite  limestone  , 

Trenton  limestone  , 

Limestone  , 

Tuckahoe  marble  

Ashley  Falls  marble  , 

Snowflake  marble  

Tennessee  marble  , 

Duke  marble  

Black  marble  , 

Sutherland  Falls  marble. . , 

Conglomerate  , 

Potomac  stone    , 

Conglomerate  

Artificial  stone  


Locality. 


Hallowell,  Me  

Stark,  N.  H   

Woodbury,  Vt  

Quincy,  Mass  

Woodstock,  Md  

Richmond,  Va  

St.  Cloud,  Minn  

Portland,  Conn  

Seneca,  Md    

Nova  Scotia  

McBride's  Corners,  O  

Berea,  O  

Baltimore,  Md   

Bedford,  Ind  

Hamilton  County,  O  

Springfield,  Penn  

Owen  Sound,  P.  O  

Montreal,  P.  Q  

Isle  La  Motte,  Vt  

Westchester  County,  N,  Y. 

Ashley  Falls,  N.  Y...  

Westchester  County,  N.Y. . 

Dougherty's  Quarry,  East 
Tennessee    

Near  Harper's  Ferry,  Va. . . 

Isle  La  Motte,  Vt  

Rutland,  Vt  

Roxbury,  Mass  

Point  of  Rocks,  Md  

'  aps  a  La  Aisle,  P.  Q  

MclMurtire  and  Chamber- 
lain Patent   


Weight  per  cubic 
foot  in  pounds. 

Ratio  of 
absorption. 

1  First  appearance 
of  injury.  De- 
grees F. 

First  appearance 
of  cracking  or 
crumbling.  De- 
grees F. 

General  cracking 
and  friability. 
Degrees  F. 

Rendered  worth- 
less.   Deg.  F. 

Melted  or  de- 
stroyed. I)e- 

164.8 

1-79U 

800 

900 

95ri 

1,000 

1,100 

164.1 

1-534 

600 

700 

800 

850 

950 

165.8 

1-784 

800 

900 

950 

1,000 

1,200 

166.2 

1-650 

750 

800 

8.0 

900 

1,000 

165.5 

1-394 

700 

750 

800 

900 

900 

167.7 

1-402 

750 

800 

850 

900 

1,000 

168.2 

1-280 

700 

700 

800 

850 

900 

148.7 

1-27 

850 

900 

9.50 

1,000 

1,100 

150.6 

1-40 

900 

1,000 

1,100 

1,200 

1,200 

151.5 

1-240 

900 

950 

1,000 

1,000 

1,100 

145.8 

1-28 

800 

850 

900 

1.000 

1,100 

140.8 

1-20 

850 

900 

9.50 

1,000 

1,000 

181.8 

2-340 

900 

1,000 

1,100 

1,200 

1,200 

ln4  8 

1-280 

850 

900 

1,000 

1.200 

1,200 

137.7 

1-28 

850 

900 

950 

1,200 

1,200 

it;6.6 

1-280 

850 

850 

90(1 

1,0(0 

1,200 

160.6 

1-480 

850 

900 

1,100 

1,200 

1,200 

169.1 

1-316 

900 

950 

1,000 

1,200 

1,200 

168.5 

1-320 

950 

l.COO 

1.100 

1,200 

1,900 

174  6 

1-298 

900 

1,000 

1,200 

1,200 

1,200 

171.3 

1-280 

900 

1,000 

1,100 

1,200 

1,200 

178.0 

1-380 

950 

950 

1,000 

i,-.oo 

1,200 

169  4 

1-320 

950 

9.M) 

1,000 

1,200 

1,200 

175.7 

1-340 

1,000 

1,000 

1,100 

1,200 

1,200 

176.6 

1-320 

1.000 

l.ono 

1,100 

1.200 

1,200 

166.6 

1-342 

1,000 

1,000 
800 

1,100 

1,200 

1,200 

169.2 

1-49 

700 

900 

1,000 

1,000 

170  2 

1-60 

600 

700 

800 

900 

900 

165.3 

1-80 

600 

700 

800 

000 

900 

139.7 

1-280 

750 

m 

1,100 

1,200 

*  From  "Notes  on  Buildinpr  Stones,"  by  Dr.  Hiram  Cuttins;.  Montpelier,  Vt.,  i88o. 

"The  experience  of  the  citizens  of  North  Arkansas  is  that  marble  is  much  superior 
to  the  sandstone  in  withstanding  heat;  and  because  of  this  fact,  where  chimneys  are 
built  of  sandstone  the  fireplaces  are  lined  with  marble." 

See  also  "The  Fire-Resisting  Qualities  of  Some  New  Jersey  Building  Stones,"  by 
W.  E.  McCourt,  in  Annual  Report  of  the  State  Geologist,  1907. 


892 


BUILDING  CONSTRUCTION. 


TABLE  Q.* 

Table  Q  shows  the  principal  mineralogical,  chemical,  and  physical 
characteristics  of  38  kinds  of  slate  described  by  Mr.  T.  Nelson  Dale 
in  Bulletin  No.  275,  Series  A.,  Economic  Geology,  63,  "Slate 
Deposits  and  Slate  Industry  of  the  United  States,"  for  1906,  as  far 
as  these  manifestly  bear  upon  their  economic  value.  These  slates 
are  from  Arkansas,  California,  Maine,  Maryland,  New  York,  Penn- 
sylvania, Vermont,  Virginia  and  West  Virginia.  The  columns 
headed  ''strength"  and  "toughness"  refer  to  the  tests  by  Professor 
Mansfield  Merriman,  whose  methods  of  experimentation  are 
described  on  page  47  of  the  Bulletin  referred  to.  "Microscopic 
texture,"  refers  primarily  to  the  matrix  or  body  of  the  slate.  By 
"crystalline"  is  meant  that  the  matrix  consists  of  interlacing  and 
overlapping  scales  and  fibers  of  muscovite  and  is,  therefore,  a  mica- 
slate  or  technically  a  phyllite-slate,  although  it  may  inclose  unaltered 
particles  of  sedimentary  origin.  Such  a  slate  should  have,  other 
things  being  equal,  greater  elasticity  (toughness)  and  strength  than 
one  in  which  there  is  no  such  texture,  or  in  which  it  is  only  incipient. 
The  fineness  or  coarseness  of  this  crystalline  texture  probably  has 
a  bearing  upon  the  strength  and  toughness  of  the  slate,  but  physi- 
cal data  are  not  sufficient  to  show  this.  The  coarse-textured  Peach 
Bottom  slates,  which  really  approach  a  mica  schist,  are  the  strongest 
of  the  twelve  kinds  of  American  slates  tested,  but  they  are  less 
flexible  than  all  the  other  kinds  tested.  In  the  "grade  of  fissility,"  i 
signifies  a  perfect  slaty  cleavage  and  4  a  very  imperfect  one.  The 
column  of  "chief  mineral  constituents"  includes  only  the  four  or  five 
principal  ones  seen  under  the  microscope,  or  whose  presence  has 
been  otherwise  determined,  and  these  are  given  in  the  descending 
order  of  their  probable  abundance. 


APPENDIX. 


893 


^  O 


5  5 


=  O 
w  0-0 


e4 


its 


U    Q    O  O 


o  ;S 

TJ  to 


C  m 

aj  o 

>  Pi 


c  ^ 

c 


PQ    Q    K    O    1-1  Q 


w  ,  , 


3  c  o 


£  c  - 

c  ^  5 


is 


O       OtS  O  O)  M 

dPL,  uCl,  30.  b 


W     M  CO 


J!L  ►-^  ►-I 

1^    ^    ^    H  O 


:5  o 

^  . 

o     c  c 

M  ^  c3  3 

O  ^ 


•56 
"HQ 


a  to 
^  o 


H.2 


894  BUILDING  CONSTRUCTION. 


^  o 


a    c    c  .  c 


2  o 


o 


-  ►5' 


-3 


c  >i 


>    >  ^ 


brown . 

c 

c 

>> 

gray 

brow 

aek. 

0) 

bi 

^  >> 

>> 

k  gra 

>-  c3 

o3  (-1 

c3 
i-> 

r/3 

a 

m 
5 

plis 

ish 

-a  M 

-0 

>. 

0) 

3 

a; 

Pi 

O 

P. 

m 

> 

Q 

> 

P^  o 


o 


ass 


11 

w)  S 


M     O  Ph 


S 

P-i  P> 


o  o 


2 

O  > 


APPENDIX. 


89s 


M  CO 
3  to 


+i  a    CO  - 


.2 

to"3 

2 


P  cc  a>  o 
C  C-C 
to  Oj::  t« 

o  o  =3  c 


2  aj:S+3 
ft  -1^ 


ft  os 

O  yi 


■5S  1^ 

Cft=  ° 

=^  £     3  -S  ^ 

to  Oj  O  £  Q> 

a^  a>t-  g-3  ^  to 

5  «  .  cfQ  o  o 

O      ftC^  g  g 

6  c  ^-«:>  oca 
:=i  oj  "55  «o     o  o 

«  S  -CD 


O  OJ 
ft^ 


o 


3  3  to 

O  o  to  . 

^  2  te 

O  O  c  g 

C  "3  ^ 


c  &  o  c  c 
h-!  +^  01  ^  ^ 

ftTH 

a;  u-^  ^  G 
^H  c3  ^  .0 

3  ft°0=  t„ 


fcC      O  4j  rt 

CO 


S  C  ,0^ 
i=  ft 
5  ^  O  G 

?  c 

o 
ft 


^  >-<  c 

0)  OJ  o 

>>a2 


C  O  •  0)-" 
O  ^^^^ 


c  S  c 

O  3  r  (H  — 

oQ    to  a  _ 
cj        c  o 

to  o  fS, 


(N  O 
CO  o 

(M  r-( 


"  /Tl 


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•  CO  -2; 


c  a 
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H  a 


c  .:=;  0)  o 


a; 


bjo 


0 


-^^  f-i  ic  C  ^ 
uO-^  o 

s_  t<  t-.  s-i  :3 

c3  03 
3  3  3  3 

cr  cr  cr  cr 


ftX3- 

sT  6 


ft-i3 


to  to  t»  to  to 


-(-^  -t^  'J^ 


to  to  to  to  CO 
3  3  3  3  3 


to  .S 
3  — 


£3 

O)  rj 
3  Ct 

o 

rS  r 

>  > 

O  c  o 

O  o  u 

to  r  to 

3-^  3 


O  o  ft 


c5  c3  o3 
3  3  3  3 

cr  cr  o"  c 

(j3  c«  c3 
0000 


>  >  >  > 
0000 
0000 

to  73  CO  CO 

3  3  3  3 


Grade 
of  fis- 
sility 

<u 

to 

Arkanf 

CO      rH      (M  (M      (M  . 


COCOIMiMCO 


BUILDING  CONSTRUCTION. 


£i  D  c  o  • 


-2  >''Sr- 
5  ^  o  c 


sal 


S  «^  o  2  S 

3  o  .  S 

&  a  c  o 


oi-^  a;  .2  »  a=:    -s ^ 

(-^      rr,  Q,o  Js 


^  S  O  S  ^fe  I  3 


;2  >■ 


O  ci3  N  , 


?  c 


T^^-S  C  O  ^  O 

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■3  C  CO  O  03  O  , 

^          g-^  O**-  OJ  D 

fcl   3   O  L,  fcn 

_M^^oc;oc.  o 


0^ 

Si  o  l-S'S'S  S  I       o|  1^  I  ° 


m  >-  c3 p-4 »J 0:;  ■♦^  t»  C  M  ?' 

5^  p 


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c|i 

a 

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^  §S  2 

C  0}  o 
C  OJ  o 

P5  Q 


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g  So 

m  0)  a 


o 

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o  . 

CO 

Pi  3 
o 

§^ 


o§ 

o  « 
c  2  o 

S  c 


S  5  aEH 


a  to 


3j3 


lOGO 

oo 


OiMOOOO 


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1,  > 


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J3  OJ 


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>  > 

o  o  c 

to  OJ-C 

3  3  « 


a^  ^ 


^  o 
S3 


t-  s-      tH  _, 


O 

3  •■^ 


^  c3  ; 


>>J=  3 

a  «  cr 

3  3  ^  cs 


>  >  O  >  _  _ 

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3  3  «^  ^3  3  a 


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:  :  ^ 

6  6> 


APPENDIX. 


897 


ADDITION  DATA  TO  ACCOMPANY  TABLES  Q.  * 

To  the  comparative  data  of  the  preceding  Tables  Q  should  be 
wadded  the  results  of  a  few  tests  not  easily  tabulated. 

Professor  Mansfield  Merriman's  later  corrosion  tests  show  the 
following  percentages  of  loss  in  weight  after  immersion  in  acid  solu- 
tion for  360  hours:  Pennsylvania  slates,  1.68  to  2.76;  Peach  Bot- 
tom, I.I  I  to  1.29;  red  of  New  York  and  Vermont,  0.25.  During 
this  test  the  Pennsylvania  slates  become  a  grayish  white,  some  of 
the  Peach  Bottom  slates  change  but  slightly,  others  are  almost  un- 
affected ;  the  red  slates  likewise  remain  almost  unaffected.'^ 

Mr.  E.  H.  S.  Bailey's  tests  of  porosity  give  these  indices  of  poros- 
ity:  ''Hard  Vein"  Pennsylvania  Chapman,  o.ii — 0.14;  Daniel  quarry, 
0.14;  Belfast  quarry,  0.25;  red  of  New  York  and  Vermont,  0.21.^ 

Mr.  J.  F.  William's  tests  of  the  compression  of  columns  of  slate  10 
inches  in  length  by  i  inch  in  cross-section  with  the  cleavage  vertical, 
show  that  the  purplish  of  the  unfading  green  series  of  Vermont 
stands  20,000  pounds,  the  unfading  green,  16,020  pounds  and  the  red 
of  New  York  and  Vermont,  17,730  pounds. 

The  following  results  of  various  tests  of  Maine  (Monson)  slate 
made  at  the  United  States  Arsenal  at  Watertown,  Mass.,  were 
republished  from  the  War  Department  reports  in  the  Twentieth 
Annual  Report  of  the  United  States  Geological  Survey,  Part  VI 
(continued),  1899,  p.  395: 

POUNDS. 

Maximum  fiber  stress  per  square  inch   7'67i 

Shearing  test  per  square  inch   2,192 

Ultimate  compressive  strength  per  square  inch   19^510 

Coefficient  of  expansion,  0.000005. 

The  relative  commercial  value  of  several  slates  is  an  index  of 
their  physical  characteristics.  Mathews,  in  1898,  gave  these  prices 
for  slates  14  by  7  inches,  three-sixteenths  thick,  per  square;  Peach 
Bottom,  $4.85;  Northampton  County,  Pa.,  $3.50;  Lehigh  County, 
Pa.,  $3.40— $3.95;  Maine  (No.  i),  $6.40;  Arvonia,  Va.,  $3.60; 
unfading  green,  Vermont,  $4.50;  red,  New  York,  $11. 


a  Trans.  Am.  Soc.  Civ.  Eng.,  vol.  32,  p.  538. 
h  Loc.  cit.,  p.  542. 

c  Loc.  cit.,  p.  132  (see  Bibliography,  p.  145  of  Mr.  Dale's  Bulletin,  No.  275). 


898 


BUILDING  CONSTRUCTION. 


'  The  following  prices  per  square  for  slates,  No.  i  quality,  16  by 
8  inches,  f.  o.  b.,  were  obtained  by  Doctor  Day  from  producers 
for  January,  1905:  Peach  Bottom,  $6.35;  Monson,  Me.,  $7.20; 
red.  New  York,  $11;  Bangor,  Pa.,  $5.75;  Albion,  Pa.,  $5;  Pen 
Argyl,  Pa.,  $4.75  ;  Chapman,  Pa.,  hard  vein,  $5.25  ;  Slatington,  Pa., 
$4.50  to  $5  ;  unfading  green,  Vermont,  $4.50  to  $5.25  ;  sea  green, 
Vermont,  $3.50;  Virginia,  $5  to  $5.50. 
Slates  may  be  classified  as  follows : 


CLASSIFICATION  OF  SLATE. 

(I)  Aqueous  sedimentary. 

(A)  Clay  slates:    Matrix  without  any  or  with  but  very  faint 

aggregate  polarization. 

(B)  Mica  slates:    Matrix  with  marked  aggregate  polarization. 

(1)  Fading:    With  sufficient  FeCOg   to   discolor  con- 

siderably on  prolonged  exposure. 

(a)  Carbonaceous  or  graphitic. 

(b)  Chloritic  (greenish). 

(c)  Hematitic  and  chloritic  (purplish). 

(2)  Unfading:    Without  sufficient  FeCOg  to  produce 

any  but  very  slight  discoloration  on  prolonged 
exposure. 

(a)  Graphitic. 

(b)  Hematitic  (reddish). 

(c)  Chloritic  (greenish). 

(d)  Hematitic  and  chloritic  (purplish). 

(H)  Igneous. 

(A)  Ash  slates. 

(B)  Dike  slates. 

In  accordance  with  this  scheme  of  classification  of  slates,  most 
of  the  slates  whose  characteristics  are  given  in  the  preceding  Table. 
Q  are  here  arranged  systematically : 


APPENDIX. 


899 


(A)  Clay-slates  (Fading)  Martinsburg,  W.  Va. 

(a)  Carhonace- 


(B)  Mica- slates 


(Fading^ 


Lehigh  and  Northhamp- 
ton counties,  Pa. 
Benson,  Vt. 


(Unfad- 
ing) 


o  u  s  or 
graphitic 
(Black- 
ish). 

(b)  Chloritic  (greenish).    "Sea  green," 

Vermont. 

(c)  Hematitic  and  Chloritic  (purplish). 

Purplish  of  Pawlet  and  Poultney, 
Vt. 

Peach  Bottom,  Pa.  and 

(a)  Graphitic  Md. 

or  carbo-  Arvonia,  Va. 
naceous  [Northfield,  Vt. 
(black-  Brownville,Monson,Me. 
ish).  North  Blanchard,  Me. 

West  Monson,  Me. 

(b)  Hematitic!  Granville,  Hampton, 

(reddish).  J     N.Y.;  Polk  Co.,  Ark. 

(c)  Chloritic    (greenish).  ''Unfading 

green,"  Vermont. 

(d)  Hematitic 


and  chlo- 
ritic (pur- 
phsh). 


Purplish  of  Fair  Haven, 
Vt. 

Thurston,  Md. 


TABLE  R.* 


The  following  table  shows  the  number  of  permits  and  the  cost  of 
buildings  erected  thereunder  in  the  leading  cities  of  the  country  in 
1905  and  1906,  the  increase  or  decrease  in  the  cost  of  the  buildings 
erected  in  each  city  in  1906,  and  the  total  increase,  together  with 
the  percentage  of  increase  or  decrease  in  each  case,  and  the  per- 
centage of  the  total  increase ;  also  the  number  and  value  of  the 
fire-proof  buildings,  with  their  cost,  and  the  number  of  wooden 
buildings,  with  their  cost.  In  some  instances  more  than  one  build- 
ing is  erected  under  the  same  permit;  the  cost  given  is  that  of. 
the  building  or  buildings  erected.  » 


900 


BUILDING  CONSTRUCTION. 


TABLE  R.* 

Building  Operations  in  the  Leading  Cities  of  the  United 
States  in  1905  and  1906. 


1905 

1906 

Number 

Number 

Percent- 

of per- 

Cost of 

of  per- 

Cost of 

Gain  (+)  or 

age  of 

mits  or 
build- 

buildings 

mits  or 
build- 

buildings 

lo 

ss  (, — )  in 
1906 

gain  or 
loss  in 

ings 

ings 

1906 

816 

$2,412,570 

713 

$2,080,634 

$331,936 

3,499 

3,312,931 

3,741 

5,156,149 

+ 

1,843.218 

+ 

55 

63 

2,976 

16,638,200 

2,826 

12,619,970 

4,018,230 

24 

15 

2,249 

12,364,747 

3,328 

23,064,741 

+  10,699,994 

+ 

86 

53 

19,679 

73,017,706 

18,083 

71,442,148 

1  ^^7^  fi'^S 
1 ,0  1  tJ,OOo 

2 

15 

2,886 

7,401,006 

2,867 

8,686,030 

+ 

17 

36 

470 

1,659,875 

457 

1,458,105 

901  770 

12 

15 

16,150 

65,000,000 

10,641 

64,709,325 

290,675 

44 

3,307 

9,709,450 

2,130 

7,065,746 

2,643,704 

27 

22 

4,976 

9,777,145 

7,553 

12,972,974 

+ 

3,195,829 

+ 

32 

68 

2,133 

5,107,400 

2,025 

4,006,175 

1,101,225 

21 

56 

1,176 

2,350,000 

1,223 

2,898,380 

+ 

548,380 

+ 

23 

33 

2.455 

6,374,537 

2,461 

7,000,996 

626,459 

+ 

9 

82 

4,021 

10,462,100 

4,105 

13,275,250 

+ 

2,813,150 

+ 

26 
6 

88 

291 

885,625 

275 

939,325 

+ 

53,700 

+ 

06 

1,486 

2,145,265 

1,250 

2,181,307 

+ 

36,042 

+ 

1 

68 

664 

3,076,092 

652 

3,732,915 

+ 

656,823 

+ 

21 

35 

4,041 

7,225,325 

3,825 

5,530,998 

1,694,327 

23 

44 

1,352 

3,330,522 

1,503 

4,334,244 

+ 

1,003,722 

+ 

30 

13 

818 

1,172,093 

541 

3,622,670 

+ 

2,450,577 

+  209 

07 

4,437 

10,917,024 

3,993 

10,765,480 

151,544 

38 

9,543 

15,382,057 

9,358 

18,502,446 

+ 

3,120,389 

+ 

20 

28 

2,255 

4,506,382 

2,916 

5,116,917 

+ 

610,535 

+ 

13 

54 

251 

878,090 

353 

901,745 

+ 

23,655 

+ 

2 

69 

2,882 

3,554,883 

2,549 

4,346,767 

+ 

791,884 

+ 

22 

27 

4,166 

9,806,729 

3,782 

9,713,284 

93,445 

95 

4,825 

8,905,205 

4,724 

9,466,150 

+ 

560,945 

+ 

6 

29 

5,636 

2,609,889 

5,124 

2,840,212 

+ 

230,323 

+ 
+ 

8 

82 

2,379 

10,214,615 

1,946 

10,411,328 

+ 

196,713 

1 

92 

'467 

2,143,240 

687 

3,018,890 

+ 

875,650 

+ 

40 

85 

1,970 
10,043 

4,070,077 
178,032,527 

5,098,773 
154,964,655 

1,028,696 
23,067,872 

+ 

25 
12 

27 
95 

8,573 

885 

4,387,464 

1,093 

4,273,050 

114,414 

2 

60 

15,933 

34,416,745 

17.872 

40,711,510 

+ 

6,294,765 

+ 

18 

28 

4,273 

17,159,443 

3,738 

15,370,047 

1.789,396 

10 

42 

1,358 

4,562,950 

1,350 

3,983.300 

579,650 

12 

70 

1.548 

2,791,065 

1,347 

1,645,135 

1,145,930 

41 

05 

451 

1,501,000 

740 

2,504,895 

4- 

1.003,895 

+ 

66 

88 

1,707 

5,676,624 

1,373 

6,175,478 

+ 

498,854 

+ 

8 

78 

877 

670,195 

898 

1,052,746 

+ 

382.551 

+ 

57 

08 

8,285 

23,434,734 

8,988 

29,938,693 

+ 

6,503.959 

+ 

27 

74 

1,657 

8,536,345 

2,813 

9,537,449 

+ 

1.001,104 

+ 

11 

72 

5,420 

18,268.753 

5,686 

34,927,396 

+  16,658,643 

+ 

91 

18 

1.144 

2,212,929 

1,097 

2,174,075 

38,854 

1 

75 

7,677 

6,704,784 

7,194 

11,875,397 

+ 

5,170,613 

+ 

77 

11 

837 

2,275,610 

1,057 

3,313,261 

+ 

1,037,651 

+ 

45 

59 

1.139 

3,087,142 

1,759 

4,696,058 

+ 

1,608,916 

+ 

52 

12 

7,577 

12,308,943 

8,453 

11,668,347 

640,596 

5 

20 

739 

2,182,840 

912 

2,939,403 

+ 

756,563 

+ 

34 

65 

185,806 

644,620,873 

180,574 

678.710,969 

+  34,090,096 

+ 

5 

29 

City 


Allegheny,  Pa.. .  . 

Atlanta,  Ga..  . .  .  . 

Baltimore,  Md.  .  . 
Boston,  Mass .... 

Brooklyn,  N.  Y... 
Buffalo,  N.  Y. .  .  . 

Cambridge,  Mass. 

Chicago,  III  

Cincinnati,  Ohio.. 
Cleveland,  Ohio.  . 
Columbus,  Ohio.  . 
Dayton,  Ohio.  . .  . 

Denver,  Colo  

Detroit,  Mich  

Fall  River,  Mass  .  . 
Grand  Rapids, Mich 
Hartford,  Conn .  . 
Indianapolis,  Ind 
Jersey  City,  N.  J. 
Kansas  City,  Kans 
Kansas  City,  Mo. 
Los  Angeles,  Cal . 
Louisville,  Ky  .  .  . 

Lowell,  Mass  

Memphis,  Tenn .  . 
Milwaukee,. Wis.  . 
Minneapolis,  Minn 
Nashville,  Tenn.  . 

Newark,  N.  J  

New  Haven,  Conn 
New  Orleans,  La. 
New  York,  N.  Y.. 
Omaha,  Nebr.  ... 
Philadelphia,  Pa.. 

Pittsburg,  Pa  

Providence,  R.  L. 

Reading,  Pa.  

Richmond,  Va.  .  . 
Rochester,  N.  Y.. 
St.  Joseph,  Mo. .  . 

St.  Louis,  Mo  

St.  Paul,  Minn.  .  . 
San  Francisco,  Cal 

Scranton,  Pa  

Seattle,  Wash  

Syracuse,  N.  Y..  . 

Toledo,  Ohio  

Washington,  D.  C 
Worcester,  Mass.. 


*  Taken  from  "Mineral  Resources  of  the 


United  States,"  for  1906. 


APPENDIX. 


901 


TABLE  S.* 

In  1906  the  attempt  was  made  for  the  first  time  to  obtain  the 
statistics  of  the  brick  and  stone  or  fire-proof  buildings  as  compared 
with  those  of  wood.  Of  the  49  cities  reporting,  35  were  able  to 
give  figures  showing  these  classes  of  buildings,  and  the  results  are 
given  in  the  following  table: 


TABLE  S.* 

Character  of  Buildings  Erected  in  the  Leading  Cities  of  the 
United  States  in  1906. 


Brick  and  stone 


Atlanta,  Ga  

Boston,  Mass  

Brooklyn,  N.  Y  

Chicago,  ill  

Cincinnati,  Ohio.  .  . . 
Cleveland,  Ohio.  .  .  . 
Columbus,  Ohio. .  .  . 

Dayton,  Ohio  

Grand  Rapids,  Mich 

Hartford,  Conn  

Indianapolis,  Ind.  .  . 
Kansas  City,  Mo.. .  . 
Los  Angeles,  Cal .  .  . 

Louisville,  Ky  

Lowell,  Mass  

Memphis,  Tenn  

Milwaukee,  Wis.  .  .  . 
Nashville,  Tenn.  .  .  . 

Newark,  N.  J  

New  Haven,  Conn. . 
New  York.-N.  Y.... 

Omaha,  Nebr  

Philadelphia,  Pa  

Providence,  R.  L.  . . 

Reading,  Pa  

Richmond,  Va  

Rochester,  N.  Y..  .  . 

St.  Louis,  Mo  

iSan  Francisco,  Cal.. 

Scranton,  Pa!  

Seattle,  Wash  

Syracuse,  N.  Y  

Toledo,  Ohio  

Washington.  D.  C. . 
Worcester,  Mass. ... 

Total  


Wood 


Number 

Number 

of  per- 

Value 

of  per- 

Value 

134 

S2, 189.327 

1,336 

$2,167,921 

479 

14,255  431 

1,156 

5,855,231 

5,802 

55,586,860 

2,782 

9,479,465 

5,967 

58,238,393 

4,674 

6,470,932 

503 

4,691,400 

748 

1,617,290 

694 

6,694,580 

3,582 

4,953,193 

594 

2,193,075 

1,125 

1,687,300 

126 

1,319,080 

910 

1,411.870 

73 

698,681 

763 

1,175,424 

127 

2,748,900 

136 

637,800 

721 

1,954,594 

1,903 

3,030,592 

413 

5,544,000 

1,621 

3,783,710 

273 

6.489,367 

6,564 

10,536.473 

201 

2,877,015 

1,415 

1,566,530 

12 

304,109 

164 

421.155 

154 

2,193,458 

1,373 

1,782,214 

179 

3,532,328 

1,633 

4,433,820 

259 

2,056,750 

458 

484,579 

155 

5,067,445 

1,791 

4,740,929 

87 

1,571,600 

257 

1.183,100 

2,588 

129,927,135 

1,279 

5,673,110 

157 

2,614,400 

712 

1.493,560 

10,987 

33,034,770 

67 

123,450 

53 

1,187,400 

719 

1,979.400 

884 

1,631,245 
1,549,576 

293 

337 

333,207 

159 

2,414,739 

779 

3,031,702 

2,640 

27,223,734 

3,956 

993,332 

599 

16,374,092 

3,258 

14,458,894 

60 

538,015 

518 

1,197,800 

81 

5,001,150 

3,170 

4,751,329 

81 

1,564,959 

511 

1,360,737 

110 

1,629,997 

1,542 

2,525,960 

1,349 

9,405,200 

1,181 

1,089,177 

72 

1,135,295 

394 

1,067.105 

37,066 

415.438,100 

52.814 

107,498.291 

Of  the  total  number  of  permits  or  buildings,  37,066,  or  41.24  per 
cent,  were  brick  or  stone  buildings,  and  52,814,  or  58.76  per  cent, 


*  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


902 


BUILDING  CONSTRUCTION. 


were  wooden  buildings.  The  total  value  of  the  new  buildings  in 
these  cities  was  $522,936,391.  Of  this,  $415,438,100,  or  79.44  per 
cent,  represented  buildings  of  stone,  brick,  or  other  so-called  fire- 
proof material,  and  $107,498,291,  or  20.56  per  cent,  represented 
wooden  buildings.  The  number  of  wooden  buildings  even  in  these 
large  cities  is  considerably  greater  (42.49  per  cent)  than  the  num- 
ber of  fire-proof  buildings,  but  the  value  of  the  wooden  buildings 
was  only  a  little  more  than  one-fourth  of  that  of  the  fire-proof 
buildings.  The  average  value  of  each  of  the  fire-proof  buildings 
was  $11,208,  while  the  wooden  buildings  averaged  only  $2,035. 

New  York  leads  in  the  value  of  its  fire-proof  buildings,  though 
the  number  erected  was  not  very  large.  The  average  value  per 
building  was  $50,204.  There  were  no  wooden  buildings  erected  in 
the  borough  of  Manhattan,  but  in  the  Bronx  1,279  were  erected  in 
1906,  with  an  average  value  of  $4,436.  Chicago  was  second  in  value 
of  fire-proof  buildings,  though  the  average  value  per  building  was 
but  $9,760,  and  Brooklyn  was  third,  with  an  average  value  of  $9,581. 
Philadelphia  reported  the  largest  number  of  brick  buildings,  10,987, 
of  an  average  value  of  $3,007.  In  St.  Louis  the  average  value  of 
fire-proof  buildings  was  $10,312. 


TABLE  T.* 

In  the  following  table  will  be  found  a  comparison  of  the  several 
varieties  of  clay  products  marketed  in  1905  and  1906,  showing  the 
actual  gain  or  loss  in  each  variety  and  the  percentage  of  gain  or 
loss  in  each  variety : 

This  table,  more  than  any  other,  exhibits  the  industry  in  1906  as 
compared  with  1905  and  is  interesting  as  giving  the  status  of  the 
various  branches.  It  will  be  observed  that  only  three  products 
showed  a  decrease  from  1905,  and  in  the  only  important  one,  com- 
mon brick,  the  loss  was  so  small  as  to  be  negligible.  All  other 
important  branches  showed  large  gains  in  1906. 

The  product  showing  the  largest  actual  gain  was  fire-brick,  which 
increased  $1,471,464,  or  11.55  P^^  cent.  Next  to  common  brick  this- 
is  the  product  of  largest  value,  reporting  $14,206,868,  as  against 
$12,735,404  in  1905. 

The  next  largest  actual  gain  was  in  vitrified  paving,  $1,154,058,. 


APPENDIX. 


903 


TABLE  T.* 

Value  of  the  Products  of  Clay  in  the  United  States  in  1905 
AND  1906,  WITH  Increase  or  Decrease. 


i  Cell 

Increase  in 

age  of 

Product 

1905 

1906 

1906 

increase 

in  IQOfi 

- 

«R1    QOy)  QQQ 

CA1    QOO  AO^ 

a$VJo,D8/ 

aO .  15 

Vitrified  paving  brick  or  block  

6,703,710 

7.857,768 

1,154,058 

17.22 

Front  brick  

7,108,092 

7,895,323 

787,231 

11  .08 

Fancv  or  ornamental  brick  

293,907 

207,119 

«86,788 

a29 . 53 

636,279 

773,104 

136.825 

21.50 

Drain  tile  

5,850,210 

6,543,289 

693.079 

11.85 

Sewer  pipe  

10,097.089 

11,114,967 

1,017,878 

10.08 

Architectural  terra-cotta  

5,003,158 

5,739,460 

736.302 

14.72 

Fire-proofing  and  terra-cotta  lumber  . 

3,004,526 

3,652,181 

647,655 

21.56 

Hollow  buikling  tile  or  blocks  

1,094.267 

934,357 

al59,910 

al4.61 

3,647,726 

4,634,898 

987,172 

27.06 

645,432 

743,414 

97,982 

15.18 

12,735,404 

14.206.868 

1,471.464 

11.55 

3,564,111 

3,988,394 

424,283 

11.90 

Total  brick  and  tile  '.  . 

121,778,294 

129,591,838 

7,813,544 

6.42 

27,918,894 

31,440,884 

3,521.990 

12.62 

149,697,188 

161,032,722 

11,335,534 

7.57 

a  Decrease. 


or  17.22  per  cent.  The  year  1905  was  unquestionably  below  the 
normal  in  this  industry,  owing  to  local  conditions,  and  in  1906  the 
industry  was  where  it  should  normally  have  been.  The  undoubted 
merit  of  vitrified  brick  when  properly  laid  as  a  paving  material  is 
becoming  realized  more  and  more,  partly  as  a  result  of  the  educa- 
tional campaign  carried  on  by  the  makers  of  this  product,  and  its 
future  increased  use  seems  assured.  The  use  of  this  variety  of  brick 
in  buildings  also  is  increasing,  as  its  advantages  for  this  character 
of  work  become  known. 

The  product  showing  the  largest  proportional  gain  was  tile  (not 
drain)  including  wall,  floor,  and  roofing  tile;  this  product^showed  a 
gain  of  27.06  per  cent  and  is  likely  to  continue  to  show  large  propor- 
tional gains,  though  the  actual  gain  was  but  $987,172.  This  product 
is  the  fourth  in  actual  gain,  being  exceeded  only  by  fire-brick, 
vitrified  brick,  and  sewer  pipe. 


*  Taken  from  "Mineral  Resources  of  the  United  States,"  for  1906. 


904 


BUILDING  CONSTRUCTION. 


TABLE  U.* 

The  following  table  shows  the  products  of  clay  in  the  United 
States  from  1897  to  1906  inclusive,  by  varieties  of  product,  together 
with  the  total  for  each  year  and  the  number  of  operating  firms 
reported. 

This  table  shows  the  wonderful  growth  of  this  industry  and  its 
great  importance.  In  these  ten  years  the  value  of  clay  products 
has  ^increased  nearly  100,000,000,  or  158.23  per  cent,  the  exact 
figures  being  from  $62,359,991  in  1897  to  $161,032,722  in  1906. 

Only  three  products  failed  to  reach  their  maximum  value  in  1906^ 
namely :  common  brick,  fancy  or  ornamental  brick,  and  hollow 
building  tile  or  block,  and  in  the  value  of  these  products  the 
decrease  from  the  maximum  was  very  slight.  In  fact,  although  the 
value  of  the  common  brick  did  not  equal  the  maximum  of  1905, 
the  quantity  reached  a  maximum  of  10,027,039,000.  Fancy  or 
ornamental  brick  and  hollow  building  brick  or  tile  have  for  some 
years  been  decreasing  almost  steadily.  Common  brick  increased 
from  the  minimum,  5,292,532,000  in  1897,  to  10,027,039,000  in 
1906,  an  increase  of  4,734,507,000,  or  89.45  per  cent,  in  ten  years ; 
the  value  ranged  from  $26,430,207  in  1897  to  the  maximum, 
$61,394,383  in  1905,  a  gain  of  $34,964,176  or  132  per  cent.  The 
price  per  thousand  varied  from  $4.99  in  1897  to  $6.25  in  1905. 


• 


APPENDIX. 


905 


TABLE  U.* 

Products  of  Clay  in  the  United   States,   1897 — 1906,  by 

Varieties. 


No.  of 

Common  brick 

Vitrified  paving  brick 

Year 

operating 
firms  re- 
tJorting 

Quantity 
(thousands) 

Value 

Average 
price  per 
thousand 

Quantity 
(thousands) 

Value 

Average 
price  per 
thousand 

1897 .... 

1898  

1899  

1900  

19€1 .... 

1902  

1903  

1904  

1905  

1906  

5,424 
5,971 
6,962 
6,475 
0,421 
6.046 
6,034 
6,108 
5,925 
5,857 

5,292,532 
5,867,415 
7,695,305 
7,140,622 
8,038,579 
8,475,067 
8,463,683 
8,665,171 
9,817,355 
10,027.039 

$26,430,207 
30,980,704 
39,887,522 
38,621.514 
45,503,076 
48.885,869 
50,532,075 
51,768,558 
61,394,383 
61,300,696 

$4.99 
5.28 
5.18 
5.41 
5.66 
5.77 
5.97 
5.97 
6.25 
6.11 

435,851 
474,419 
580,751 
546,679 
605,077 
617,192 
654,499 
735,489 
665,879 
751,974 

$3,582,037 
4,016,822 
4,750,424 

.4,764,124 
5,484,134 
5,744,530 
6,453,849 
7,557,425 
6,703,710 
7,857,768 

.     $8  22 
8.47 
8.18 
8.71 
9.06 
9.31 
9.86 
10.28 
10,07 
10.45 

Front  brick 

Fancy  or 

Enam- 

Year 

Quantity 

Average 

ornamen- 

eled 

Fire-brick 

Stove 

Drain  tile 

Value 

price  per 

tal  brick 

brick 

(value) 

lining 

(value) 

(thou- 

thou- 

(value) 

(value) 

(value) 

sands) 

sand 

1897. . . . 

310,918 

$3,855,033 

$12.40 

$685,048 

(a) 

$4,094,704 

(6) 

$2,623,305 

1898. . .  . 

295,833 

3,572,385 

12.08 

358,372 

$279,993 

6,093,071 

{b) 

3,115,318 

1899. . . . 

438,817 

4,767,343 

10.86 

476,191 

329,969 

8,641,882 

$416,235 

.3,682,394 

1900. . .  . 

344,516 

3,864,670 

11.09 

289,698 

323,630 

9,830,517 

462,541 

2,976,281 

1901. . . . 

415,343 

4,709,737 

11.34 

372,131 

463,709 

9,870,421 

423,371 

3,143,001 

1902. .  .  . 

458,391 

5,318,008 

11.60 

335,290 

471,163 

11,970,511 

630,924 

3,506,787 

1903. . . . 

433,016 

5,402,861 

12.48 

328,387 

569,689 

614,062,369 

ih) 

4,639,214 

1904... . 

434,351 

5,560,131 

12.80 

300,233 

545,397 

11,167,972 

il>) 

5,348,555 

1905... . 

541,590 

7,108,092 

13. 12 

293,907 

636,279 

12,735,404 

645,432 

5,850,210 

1906. . . . 

617,469 

7,895,323 

12.79 

207,119 

773,104 

14,206,868 

743,414 

6,543,289 

Archi- 

V 

Hollow 

Sewer 

tectural 

Fire- 

building 

Tile, 

Miscella- 

Year 

pipe 
(value) 

terra- 

proofing 

tile  or 

not  drain 

Pottery 

neous 

Total 

cotta 

(value) 

blocks 

(value) 

(value) 

(value) 

value 

(value) 

(value) 

1897. 

$4,069,534 

$1,841,422 

$1,979,259 

(c) 

$1,476,638 

$10,309,209 

$1,413,595 

$62,359,991 

1898. 

3,791,057 

2,043,325 

1,900,642 

(c) 

1,746,024 

14,589,224 

2,000,743 

74,487,680 

1899. 

4,560,334 

2,027,532 

1,665,066 

ic) 

1,276,300 

17,250,250 

6,065,928 

95,797,370 

1900. 

5,842,562 

2,372,568 

1,820,214 

ic) 

2,349,420 

19,798,570 

2,896,036 

96,212,345 

1901. 

6,736,969 

3,367,982 

1,860,269 

(c) 

2,867,659 

22,463,860 

2,945,268 

110,21 1,.587 

1902. 

7,174,892 

3,526,906 

3,175,593 

ic) 

3,622,863 

24,127,453 

3,678,742 

12?,!  69,531 

1903. 

8,525,369 

4,672,028 

2,708,143 

$1,153,200 

3,505,329 

25,436,052 

3,073,856 

131,062,421 

1904. 

9,187,423 

4,107,473 

2,. 502, 603 

1,126,498 

3,023,428 

25,158.270 

3,669,282 

131,023,248 

1905. 

10,097,089 

5,003,158 

3,004,526 

1,094,267 

3,647,726 

27,918,894 

3,564,111 

149,697,188 

1906. 

11,114,967 

5,739,460 

3,652,181 

934,357 

4,634,898 

31,440,884 

3,988,394 

161,032,722 

a  Enameled  brick  not  separately  classified  prior  to  1898. 

b  Stove  hning  not  separately  classified  prior  to  1899  is  included  in  fire-brick  in  1903;  in  mis- 
cellaneous in  1904. 

c  Hollow  building  tile  or  blocks  included  in  fire-proofing  prior  to  1903. 


*  Taken  from  "Mineral  Resources  of  the  United  States,'*  for  1906. 


9o6 


BUILDING  CONSTRUCTION 


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APPENDIX.  907 

TABLE  W. 
Safe  Working  Loads  for  Masonry. 

From  the  "  Architect's  and  Builder's  Pocket-Book,"  by  Frank  \\.  Kidder. 

BRICKWORK  IN  WALLS  OR  PIERS. 

Tons  per  square  foot.  Eastern  Wtstrrit 

Red  brick  in  lime  mortar   7  5 

'*  hydraulic  lime  mortar   6  » 

*'            natural  cement  mortar,  i  to  3   10  8 

Arch  or  pressed  brick  in  lime  mortar   8  6 

*'            "       "        natural  cement   12  9 

*'            "       *'        Portland  cement   15  12J 

Piers  exceeding  in  height  six  times  their  least  dimensions  should  be  increased  4  inches  in 
size  for  each  addititional  6  feet. 

STONEWORK. 
(Tons  per  square  foot.) 

Rubble  walls,  irregular  stones  „ . .  3 

**         coursed  soft  stone   2\ 

'*  '*      hard  stone   5  to  16 

Dimension  stone,  squared  in  cement : 

Sandstone  and  limestone   10  to  20 

Granite   20  to  40 

Dressed  stone,  with  |-inch  dressed  joints  in  cement: 

Granite   60 

Marble  or  limestone,  best   40 

Sandstone   30 

Height  of  columns  not  to  exceed  eight  times  least  diameter. 

/ 

CONCRETE. 

Portland  cement,  i  to  8,  6  months,  10  tons  ;  i  year,  15  to  20  tons  

Rosendale  cement,  i  to  6,  6  months,  3  tons  ;  i  year,  5  to  8  tons  

Hydraulic  lime,  best,  i  to  6   5 

HOLLOW  TILES. 
(Safe  loads  per  square  inch  of  effective  bearing  parts.) 

Hard  fire-clay  tiles   80  lbs.* 

ordinary  clay  tiles    60  " 

Porous  terra-cotta  tiles   40  '* 

MORTARS. 

(In  ^-inch  joints,  3  months  old,  tons  per  square  foot.) 

Portland  cement,  i  to  4   40< 

Rosendale  cement,  i  to  3   13 

Lime  mortar,  best   8  to  10 

Best  Portland  cement,  i  to  2,  in  ^-inch  joints  for  bedding  iron  plates   70 


*  These  loads  are  those  alh.wed  by  the  Chicag-o  Building  Ordinance. 


9o8  BUILDING  CONSTRUCTION. 


TABLE  X.* 

Thickness   of   Walls   for   the   Dwelling-house   Class  of 

Buildings. 

This  classification  includes  the  following  kinds  of  buildings:  Apartment- 
houses,  asylums,  club-houses,  dormitories,  convents,  hotels,  dwellings, 
schools,  hospitals,  studios,  laboratories,  tenements,  lodging-houses  and 
parish  buildings. 

The  total  heights  cannot  be  increased,  but  the  intermediate  heights  may 
be  varied,  the  various  heights  being  measured  to  the  nearest  tier  of  beams. 

The  following  numbers  refer  to  the  sections  in  Diagram  X,  reading 
from  left  to  right. 

No.  I.  The  walls  above  the  basement.  Dwelling-houses  not  over  three 
stories  and  basement  in  height,  not  over  20  feet  in  width  and  not  over 
55  feet  in  depth  shall  have  side  and  party-walls  at  least  8  inches  thick, 
iind  front  and  rear  walls  12  inches  thick. 

No.  2.  Walls  of  dwellings  over  20  feet  in  width  and  not  over  40  feet 
•in  height  shall  be  at  least  12  inches  thick.  Walls  of  dwellings  26  feet  in 
width  between  bearing  walls,  and  '  over  40  feet  in  height  but  not  over 
$0  feet  in  height,  shall  be  at  least  12  inches  thick  above  the  foundation 
walls.  No  wall  shall  have  a  12-inch  portion  measuring  more  than  50  feet 
in  height. 

No.  3  If  over  50  feet,  and  not  over  60  feet  in  height,  the  walls  shall 
be  at  least  16  inches  thick  in  the  story  above  the  foundation  walls  and 
thence  at  least  12  inches  thick  to  the  top. 

No.  4.  If  over  60  feet  and  not  over  75  feet  in  height,  the  walls  shall 
be  at  least  16  inches  thick  above  the  foundation  walls  to  a  height  of  25 
feet  or  to  the  nearest  tier  of  beams  and  thence  at  least  12  inches  thick  to 
the  top. 

No.  5.  If  over  75  feet,  and  not  over  100  feet  in  height,  the  walls  shall 
be  at  least  20  inches  thick  above  the  foundation  walls  to  a  height  of  40 
fee,  or  to  the  nearest  tier  of  beams;  thence  at  least  16  inches  thick  to  a 
height  of  75  feet,  or  to  the  nearest  tier  of  beams;  and  thence  at  least  12 
inches  thick  to  the  top. 

No.  6.  If  over  100  feet  and  not  over  125  feet  in  height,  the  walls  shall 
be  at  least  24  inches  thick  above  the  foundation  walls  to  a  height  of  40 
teet,  or  to  the  nearest  tier  of  beams;  thence  at  least  20  inches  thick  to  a 
llieight  of  75  feet,  or  to  the  nearest  tier  of  beams;  thence  at  least  16  inches 
thick  to  a  heigh,  of  110  feet,  or  to  the  nearest  tier  of  beams;  and  thence 
jit  least  12  inches  thick  to  the  top. 

No.  7.  If  over  125  feet,  and  not  over  150  feet  in  height,  the  walls 
shall  be  at  least  28  inches  thick  above  the  foundation  walls  to  a  height 
of  30  feet,  or  to  the  nearest  tier  of  beams;  thence  at  least  24  inches  thick 
to  a  height  of  65  feet  or  to  the  nearest  tier  of  beams;  thence  at  least  20 
inches  thick  to  a  height  of  100  feet  or  to  the  nearest  tier  of  beams;  thence 
at  least  16  inches  thick  to  a  height  of  135  feet  or  to  the  nearest  tier  of 
teams;  and  thence  at  least  12  inches  thick  to  the  top. 

♦Tables  X  and  Y,  with  the  accompanying  diagrams,  were  compiled  by  Mr.  Louis  A. 
Abramson,  and  are  based  upon  the  requirements  of  the  New  York  City  building  laws. 


9IO 


BUILDING 


CONSTRUCTION. 


TABLE  Y.* 

Thickness  of  Walls  for  the  Warehouse  Class  of  Buildings. 

This  classification  includes  the  following  kinds  of  buildings:  Armories, 
breweries,  churches,  cooperage  shops,  court-houses,  factories,  foundries, 
ja'ls,  libraries,  light-houses,  power-houses,  machine-shops,  markets,  mills, 
museums,  obervatories,  office-buildings,  police-stations,  printing-houses, 
public  assembly  buildings,  pumping  buildings,  railroad  buildings,  refriger- 
ating houses,  slaughter-houses,  stables,  stores,  sugar  refineries,  theaters, 
warehoui^es  and  wheelwright  shops. 

The  following  numbers  refer  to  the  sections  in  Diagram  Y,  reading 
from  left  to  right : 

No.  I.  The  walls  of  all  warehouses  25  feet  or  less  in  width  between 
walls  or  bearings  shall  be  at  least  12  inches  thick  to  a  height  of  40  feet 
above  the  foundation  walls. 

No.  2.  If  over  40  feet  and  not  over  60  feet  in  height,  the  walls  shall 
1)6  at  least  16  inches  thick  above  the  foundation  walls  to  a  height  of  40 
feet,  or  to  the  nearest  tier  of  beams  and  thence  at  least  12  inches  thick 
to  the  top. 

No.  3.  If  over  60  feet  and  not  over  75  feet  in  height,  the  walls  shall 
be  not  less  than  20  inches  thick  above  the  foundation  walls  to  a  height  of 
25  feet  or  to  the  nearest  tier  of  beams  and  thence  at  least  16  inches  thick 
to  the  top. 

No.  4.  If  over  75  feet  and  not  over  100  feet  in  height  the  walls 
shall  be  at  least  24  inches  thick  above  the  foundation  walls  to  a  height 
of  40  feet,  or  to  the  nearest  tier  of  beams;  thence  not  less  than  20 
inches  thick  to  a  height  of  75  feet,  or  to  the  nearest  tier  of  beams;  thence 
at   least   16   inches   thick   to   the  top. 

No.  5.  If  over  100  feet,  and  not  over  125  feet  in  height,  the  walls 
shall  be  at  least  28  inches  thick  above  the  foundation  walls  to  a  height 
of  40  feet,  or  to  the  nearest  tier  of  beams ;  thence  not  less  than  24 
inches  thick  to  a  height  of  75  feet  or  to  the  nearest  tier  of  beams; 
thence  not  less  than  20  inches  thick  to  a  height  of  110  feet  or  to 
the  nearest  tier  of  beams ;  thence  at  least  16  inches  thick  to  the  top. 

No.  6.  If  over  125  feet  and  not  over  150  feet  in  height,  the  walls  shall 
be  at  least  32  inches  thick  above  the  foundation  walls  to  a  height  of  30 
feet  or  to  the  nearest  tier  of  beams;  thence  at  least  28  inches  thick  to  a 
height  of  65  feet  or  to  the  nearest  tier  of  beams ;  thence  at  least  24  inches 
thick  to  a  height  of  100  feet  or  to  the  nearest  tier  of  beams ;  thence  at 
least  20  inches  thick  to  a  height  of  135  feet  or  to  the  nearest  tier  of  beams ; 
thence  at  least  16  inches  thick  to  the  top. 

For  walls  over  150  feet  in  height,  each  additional  25  feet  in  height,  or 
part  thereof,  next  above  the  foundation  walls  shall  be  increased  4  inches 
in  thickness.  The  uppermost  150  feet  of  wall  shall  remain  the  same  as 
specified  for  a  wall  of  that  height. 


•See  footnote  for  Table  X. 


APPENDIX, 


The  White  System  of  Fire-proofing, 


ON  pages  518  and  519  will  be  found  a  description  and  sec- 
tional drawings  of  the  system  of  fire-proofing  of  the  White 
Fire-proof    Construction    Company,    i    Madison  Avenue, 
New  York  City. 

The  system  of  reinforcement  used  by  this  company  in  its  work 
was  one  of  the  first  put  on  the  market,  and  that  at  a  time  when 
the  theory  and  method  of  reinforcing  concrete  were  comparatively 
little  understood.  It  is  interesting  to  note  that  the  successive  steps 
and  developments  in  the  line  of  concrete  reinforcement  have  dem- 
onstrated that  the  system  put  into  use  by  this  company  at  so  early 
a  date  was  correct  in  principle,  and  accords  with  the  best  practices 
of  the  present  day. 

In  addition  to  this,  it  has  always  been  the  contention  of  the 
White  Fire-proof  Construction  Company  that  the  work  covered 
under  the  head  of  *'Fire-proof  Construction"  in  a  specification 
should  include  not  only  the  fire-proof  floor  work  between  the  steel 
beams,  but  also  the  fire-proofing  with  concrete  of  all  columns  and 
other  structural  steel  members  of  a  building,  as  well  as  all  metal 
furring  and  lathing  for  ceilings,  partitions,  outside  wall  furring  and 
ornamental  plaster  effects — i.  e.,  girders,  transoms,  cornices,  vaulted 
ceilings,  penetrations,  etc.  In  a  word,  the  claim  is  made  that  the 
fire-proofing  contractor  should  follow  the  steel  framework  and  the 
outside  masonry  walls  by  installing  all  the  above-mentioned  work, 
one  part  after  the  other,  so  as  to  leave  the  entire  building  ready 
for  the  plasterer  to  start  his  work. 

As  an  illustration  of  one  of  the  many  instances  where  such  a 
course  is  desirable  may  be  mentioned  a  case  very  common  in  fire- 
proof buildings,  where  the  hangers  for  the  metal  lath  ceilings  and 
the  ornamental  framework  for  the  plaster  must  be  attached  to  the 
steel  beams  before  the  concrete  floors  are  installed,  so  as  to  avoid 
much  damage  by  cutting  and  patching  later  on.  If  all  the  above 
work  has  been  specified  and  contracted  for  under  one  head,  no 
question  of  divided  responsibility  in  connection  with  this  work  can 
arise.  Numerous  other  instances  can  be  quoted  along  the  same 
lines. 

It  would  seem  that  this  method  of  procedure  has  many  points 
in  its  favor,  not  only  from  the  builder's  standpoint,  but  from  the 
standpoint  of  the  architect  also,  both  of  whom  by  specifying  or 

912 


contracting-  for  all  of  this  work  as  a  unit  will  avoid  all  risks  of 
duplications  or  omissions. 

The  White  Fire-proof  Construction  Company  has  prepared  a 
number  of  different  skeleton  specifications  which,  in  conjunction 
with  its  catalogue,  makes  the  writing  of  the  fire-proofing  part  of 
a  building  specification  a  very  simple  matter  for  any  one,  insur- 
ing at  the  same  time  a  thoroughly  first-class  and  economical 
result.  The  very  wide  use  which  these  specifications  have  attained 
among  architects  indicates  that  specification  writers  are  quick  to 
avail  themselves  of  anything  that  proves  of  real  assistance  to  them. 

In  fire-proof  construction  there  are  a  number  of  points  which 
very  few  architects  take  the  trouble  to  mention  specifically  in  their 
specifications,  but  which  are  of  the  utmost  importance  to  the  general 
results  to  be  obtained.  Among  these  may  be  mentioned  the 
proper  spacing  of  the  tension  rods  in  the  concrete  and  the 
proper  location  of  these  rods  in  relation  to  the  under  side  of  the  con- 
crete slab.  It  is  needless  to  say  that  the  proper  location  of 
these  rods  increases  the  efficiency  of  the  construction  many  times 
over  one  in  which  they  are  put  in  in  an  improper  manner. 

Another  matter  of  the  utmost  importance  to  architects  in  specify- 
ing the  furring  and  lathing  is  the  method  in  which  the  same  should 
be  assembled.  In  the  last  few  years  the  custom  of  tying  together 
the  furring  bars  to  form  the  framework  for  the  lath  has  come 
largely  into  use,  especially  on  the  poorer  grades  of  work,  and  it  is 
a  fact  that  such  work  has  occasionally  been  passed  by  architects 
who  ordinarily  demand  a  good  quality  of  workmanship.  A 
moment's  thought  will  convince  any  one  that  the  only  proper  and 
safe  method  of  assembling  furring  is  by  bolting  the  various  parts 
together,  thus  making  a  rigid  frame  which  is  practically  proof 
against  deterioration  and  will  therefore  hold  the  plastering  together 
for  an  indefinite  period.  Furring  which  is  tied  up  has  proved  to 
be  entirely  inadequate  as  a  permanent  support  for  plastering,  and 
many  an  ornam_ental  ceiling  has  been  entirely  ruined  and  the  owner 
put  to  great  expense  within  a  few  years  of  the  completion  of  his 
building  on  this  account.  As  the  difference  in  cost  between  the 
methods  of  bolting  and  of  tying  up  furring  is  very  slight,  there 
would  not  seem  to  be  a  single  good  argument  in  favor  of  the 
latter  way  of  erecting  furring.  The  specifications  above  referred 
to  cover  these  points  very  thoroughly. 

The  White  Fire-proof  Construction  Company  also  acts  in  an 
advis(!)ry  capacity  in  connection  with  building  projects  which  offer 
new  and  difficult  problems  of  fire-proofing. 


913 


i 


» 


INDEX. 


Absorpti< 

A 

Absorption, 

bricks,   323,  328. 
sand-lime,  331,  332. 
cement  bricks,  334. 
concrete  blocks,  tests,  867. 
slates,  243. 
stones,  257. 

ratio  of,   granites,   88 r,   883,  891. 
limestone,  881,  882,  891. 
marbles,  88r,  891. 
sandstones,  881,  891. 
stone,  artificial,  891. 
stones,  881,  882,  883,  891. 
Abutments, 
arches,  285. 
concrete,  595. 

reinforced,  635. 
elliptical  arches,  286. 
stone  arches,  283. 
mortar  in,  285. 
Acid-resistance  tests, 

bricks,  sand-lime,  332. 
Acme  wall  plaster,  786,  787,  789. 
Adamant  wall  plaster,  787. 
Adhesion, 

concrete  and  reinforcements,  665. 
reinforcements  in  concrete,  663. 
steel  to  concrete  in  reinforced  work,  660. 
Adhesive  resistance, 

reinforcements,    concrete,  715. 
Adjacent  excavations, 

to  foundations  on  clay  soils,  7. 
Adjacent  lots, 

staking  out  buildings,  3. 
Agatite  wall  plaster,  786,  787,  789. 
Aggregates, 

color  of,  in  concrete  blocks,  744. 
concrete,  594. 
reinforced,  674. 
specifications,  857. 
size  for  concrete  blocks,  730,  731. 
Air-ducts  for  cold  air, 
specifications,  828. 
Air-lock, 

caissons,  plenum  system,  74. 
Moran,  used  in  caisson  works,  82. 
Air-pumps, 

caisson   foundation   construction,  75. 
Air-spaces,  hollow  walls,  372. 
Alarms,   automatic,  582. 
Alignum,  flooring,  534. 
Allunited  furring  strips, 

column  fire-proofing,  453,  454. 
steel  "furring  studs,  571,  574. 
studding,  565,  566. 
Alluvial  soils, 

safe   bearing   strength,  10. 
Alumina,   silicate  of, 

bricks,  312. 
American  Concrete  Steel  Co.,  Newark,  N. 
J., 


'R— Angle. 

concrete,    reinforced,    type    of  construc- 
tion, 703. 

American  Railway  Eng.   and  Maintenance 
of  Way  Ass'n., 
natural  cements,  specifications,  154. 
Portland  cements,   specifications,  177 
American  Society  of  Civil  Engineers, 

standard  American  form  of  briquette  for 
cement  strength  tests,  183. 
American  Society  for  Testing  Materials, 
definitions  of  Portland  cements,  161. 
fineness  of  Portland  cements,  174. 
natural  cements,  152. 

specifications,  154. 
Portland  cements,  specifications  176. 
setting  of  Portland  cements,  173. 
soundness  of  Portland  cements,  173. 
specific  gravity  of  Portland  cements,  173. 
weight  of  Portland  cements,  172. 
specifications    for    tensile     strength  of 
Portland   cements,  176. 
American   Steel   and   Wire   Co.,  Chicago, 
111., 

concrete  columns,   reinforced,   697,  698. 
steel    fabric   reinforcements,  508. 
wire  floor  reinforcement,  522. 
American    System   of    reinforced  concrete 

construction,  703. 
American  System  of  Reinforcing  for  Con- 
crete  Construction,   Chicago,  111., 
columns,     concrete,     spiral  reinforcing, 
699. 

concrete,    reinforced,    type    of  construc- 
tion, 704,  705. 
Anchor,  Anchors, 
ashlar,  296,  300. 
belt-courses  of  brick,  342. 
brick  facing  on  concrete,  860. 
brick  walls,  354. 
brickwork,  359,  366. 

concrete  block  walls,  to  joists,  740,  741. 

coping  stones,  293. 

cornices  of  brick,  342. 

gable  copings,  293. 

iron,  stone  columns,  292. 

joists  to  concrete  block  walls,  740. 

relieving-beams,  285. 

rust,  300. 

stone   architraves,  292. 

columns,  292. 

cornices,  292. 

entablatures,  292. 

friezes,  292. 

porches,  292. 
stonework,  specifications,  823. 
terra-cotta,  architectural,  836. 
Anchoring, 

ashlar  work,  309. 

cantilever  foundation  construction,  86. 
finials  of  stone,  310. 
gable  copings  of  stone,  309,  310. 
Angle,  Angles, 

brick  walls,  bonding,  359. 

15  • 


9i6  INDEX. 

Ans;le-bars — Ashlar. 


steel,  under  stone  caps,  277. 
stone  walls,  99, 
Angle-bars,    stone    lintel    supports,  289. 
Angle-draft  lines,  271, 
Angular  block  construction, 
concrete  blocks,  741,  742. 
Annealing,  bricks,  paving,  323. 
Apartment-houses,  . 

computing  weight  on  footings,  16. 
roofs,  brick  paving,  322. 
walls,  thickness  of,  908. 
Aqueducts,  concrete,  594. 
Arch,  Arches, 

abutments,  283,  285. 
for  bracing  area  walls,  106. 
brick,  325,  341,  379. 
backing,  284. 
cement  mortar,  285. 
factor  of  safety,  402. 
over   pavement   vaults,   asphalt  cover- 
ing, 115. 
roofs  for  sidewalk  vaults,  114. 
soffit  joints,  338. 
stability  of,  335. 

to  span  rock  fissures,  foundations,  6. 

or  stone  to  span  rock  fissures,  6. 
concrete,  595. 

blocks,  746. 
coursed-ashlar  work,  283. 
cracks,  281. 
cut-stone,  cracks,  310. 

setting,  310. 
elliptical,  282,  285. 

joints,  286. 
flat,  terra-cotta,  420. 

stone,  288,  289. 
keystones,  288. 
strength  of,  288. 
four-centered,  287. 
Gothic,  287. 
groups  of,  285. 
inverted,  93. 

long  span,  use  of  cement  mortars,  188. 
pointed,  287. 

Portland  cements,  use  of,  170. 
relieving,  277. 

Renaissance   architecture,  283. 
Richardson,  H.  H.,  284. 
rock-faced,  282. 
rowlock,  94. 

sectional  area,  of  inverted,  95. 
segmental,  285,  288. 
semi-circular,  stone,  283. 
settlements,  281. 
stability,  284. 
stilted,  281,  283. 
stone,  280. 

backing,  284. 

built-up,  284. 

centers  for,  289,  290,  291. 

cost  of,  283. 

cracks  in,  285. 

keystones,  284. 

label-moldings,  284. 

relieving-beams  over,  285. 

rubble,  289. 

spandrels,  285. 

stability  of,  281,  284. 

strength  of,  283. 

thickness  of,  284. 
terra-cotta,  flat,  420. 

and  stone  construction,  compared,  420. 
three-centered,  286, 
thrust,  285. 

trimmer  arches  of  brick,  fireplaces,  388, 

390. 
Tudor,  287. 

vault  walls,  thickness  of,  106. 


Arch-bricks,  319,  324. 
Arch-girders,  iron,  751. 
Architecture,  suburban, 

rubble  stonework  for,  264. 
Architectural  terra-cotta, 

(see  terra-cotta). 
Architraves,  stone,  292. 
Arch-rings, 

depth  of,  283,  284. 

molded,  284. 

stone  arches,  281. 

thickness  of,  for  inverted  arches,  95. 
Area,  Areas, 
bottom  of,  IT2. 
deep,  excavation  for,  113. 
draining  of,  112. 
entrance,  113. 

non-fire-proof  buildings,  438. 

semicircular,  112. 

window  and  entrance,  112. 
Area  line,  115. 
Area  steps,  1 13. 

bearing  \yall,  middle  support,  114. 

construction  of,  113. 

foundations,  level  of,  114. 

iron  string  to  support  middle,  114. 

on  hard  and  compact  soil,  113. 

plank,   supported  by  plank  strings,  114, 

setting  and  pointing,  113. 

stone,  foundation  for,  level  of,  114. 
pitch  of,  114. 

support   of  treads,  113. 
Area  walls,  loi. 

batter,  105. 

bracing,  105. 
by  arches,  106. 

coping  of,  112. 

excavation  for,  105. 

filling,  105. 

general   description,  105. 
level  of  footings,  113. 
materials,  105. 
stiffening  by  buttresses,  106. 
sustaining  street  or  alley,  105. 
thickness,  105,  112. 
Armored    concrete     (see    concrete,  rein- 
forced). 

Armories,  walls,  thickness  of,  910. 
Artificial  stone  (see  stone,  artificial). 
Asbestic  plaster  (see  plaster'). 
Asbestolith,  flooring,  534. 
Asbestos, 

flooring,   composition.  534. 
partition  plaster-blocks,  543. 
Asbestos  granite,  flooring,  534. 
Ashlar,  264. 

anchors,  296,  309. 
backing  for,  299. 
bonding,  300,  309. 
broken,  265,  295,  296. 
picked  finish,  274. 
cost  of,  265. 
general  description,  265. 
height  of  stones,  265. 
when  used,  265. 
cheapest,  264. 
coursed,  264. 
arches  in,  283. 
drawings  of,  295,  296. 
courses,  heights  of,  296. 
defects,  309. 

dimensions  for  strength,  304. 
imitated,  264. 
irregular-coursed,  265. 
laying  out,  295,  296. 
limestone,  sawed,  296. 
manner  of  laying,  264. 


INDEX. 


917 


Aslilar-'tvork— Beams. 


marble,  296. 

anchoring,  300. 
measurement  of,  307, 
natural  beds  of  stone,  309. 
•over  stone  lintels,  277. 
random-coursed,  266. 
regular-coursed,  265. 
rock-faced,  309. 

cost  of,  271. 

joints,  298. 
sandstone,  anchoring,  300. 

rubbed,  273. 

sawed,  296. 

and  limestone,  264. 
size  of  stones,  265. 
specifications,  822. 
stone,  released,  592. 
thickness,  296,  309. 
terra-cotta,  architectural,  416,  417. 
Ashlar  work,  superintendence  of,  309. 
Ash-pits,    specifications,  830. 
Ash  slates,  898. 

Aspdin,  Joseph,  inventor  of  Portland  Ce- 
ments, 163. 
Asphalt, 

application  to  walls,  109. 

coating  for  brick  arches  over  pavement 

vaults,  115. 
coating  for  cast-iron,  96. 
for  damp-proofing,  109. 
for  steel  grillage  beams,  59. 
damp-proof  courses,  367. 
damp-proofing  brick-work,  401. 
Asphalt  flooring,  533. 
Asphalt  roofing,  536. 

Associated  Expanded-Metal  Companies,  562. 
Asylums,  walls,  thickness  of,  908. 
Atlas  Portland  Cement  Co.,  New  York, 

wood  forms,  concrete  construction,  613. 
Atmospheric    action,     effect    on  building 

stones,  252. 
Atlantic  Terra-cotta  Co.,  New  York, 

terra-cotta  details,  415. 
Auger,  post,  used  to  test  character  of  soil, 
4. 

Auger  machines,  brick  manufacture,  315. 

Avistrian  tests,  floor  arches,  476. 

Axe  for  stone  dressing,  269,  271,  274. 


Backing, 
brick,  299. 

cement-brick,  concrete  block  walls,  742, 

743. 
cost  of,  299. 
cut-stonework,  299. 
of    concrete    block    walls,  863. 
plastering  in  brick  and  stone,  299. 
stone,  299. 

measurement  of,  307. 
arches,  284. 
for  rubble  walls,  264. 
with  concrete  blocks,   737,  738. 
Back-plastering,  specifications,  837. 
Baker,  Ira  O., 

bricks,  absorption,  328. 

estimating    quantities    of    materials  for 

mortars,  193. 
mortars  impervious  to  water,  196. 
Balconies, 

concrete,   reinforced,   specifications,  860. 
terra-cotta,  428. 
Ball-clay,  brick  manufacture,  glazed  bricks, 
320. 

Balusters,  iron,  stone  stairs,  294. 
Balusters     and     Balustrades,  terra-cotta, 
architectural,  417,  418,  427,  428,  431. 


Band-courses,  bricks,  colored,  346. 

Bars,  reinforcing  (see  reinforcements). 

Bars,   ribbed,   reinforcements,  506. 

Bars  versus  wire  fabrics  as  reinforcements 

for  concrete  floors,  499. 
Base,  Bases, 

center  of,  bearing  power  of  foundations, 
20. 

concrete   columns,  717. 

stone   columns,  291. 
Base  or  wall  floor  angles,  sanitary,  534. 
Baseboards,    tile,    molded,    hollow,  578. 
Base-courses   in   stone   vermiculated  work, 

274. 
Basement, 

insufficient  headroom,  cantilever  construc- 
tion, 85. 

water-proofing,  no. 
Basement  floors, 

damp-proofing  course,  no. 

thickness  when  affected  by  water,  no. 
Base-plate, 

bedding,  67. 

built-up,  67. 

cantilever  construction,  85. 
cast-iron  or  steel,  67. 
columns,  girders,  etc.,  768. 
substitution  for  beams  in  upper  course  of 
footing,  67, 
Batter-boards,  i. 
Bay-windows, 
bricks  for,  325, 
masonry,  supports  for,  752. 

supports  for  in  skeleton  construction, 
766. 

Beach  sand,  filling  for  made  land,  founda- 
tions, 9. 
Beam,  Beams, 
bearing,  295. 

bending  moments,  reinforced  concrete  de- 
sign, 661. 
cantilever,  concrete,  reinforced,  635. 
concrete,  reinforced,  647. 

adhesion  of  reinforcement,  665. 
amount   and    disposition   of  reinforce- 
ment,   652,  662. 
breadth  of,  663. 
compression  rods,  665. 
compressive    stresses,    graphical  repre- 
sentation, 651. 
constants  used  in  formulas,  652,  653, 

654,  655- 
design  of,  649. 
determination  of  size,  655. 
diagonal  tension,  648,  660. 
distribution  of  compressive  fiber  stress, 
649. 

extreme  fiber  stress  allowed,  660. 
factor   of  safety,  649. 
failure  of,  648. 

by  diagonal  tension,  650. 

by  splitting  of  concrete,  650. 

ideal,  by  steel  tension,  650. 
formulas,   650,   651,  659. 

rectangular  beams,  655. 

sources  of   differences  in,  649. 
reinforcement,  percentage  of,  652. 
stirrups,  664. 

stresses,   vertical   shear   and  diagonal 
tension,  664. 

stress-strain   curve,  649. 

T-beams,  657,  659. 
continuous,  661,  644,  645. 
false,  470,  573,  574,  576,  833. 
fire-proofing,  531,  532,  533, 

concrete,  533. 

general  considerations,  530. 
tile,  531. 


9i8 


INDEX. 


Beam-footings — Break^vatersi. 


flexure,  notes  on,  644. 

floor,  stone  lintel  supports,  306, 

furred  tile,  833. 

I-beams,  wrought-iron,  465,  466. 
laws  of  static  equilibrium,  644. 
neutral  surface,  646 
principal  stress,  lines  of,  646,  647. 
proportioning  sizes  in  needling,  120, 
restrained,  645. 
shear,  vertical,  645. 
simple  beams,  644,  645. 
steel  (see  steel  beams), 
stone,  strength  of,  305. 
strength,  comparative,   of  plain  and  re- 
inforced, 648. 
stresses  in,  644. 

supports,  concrete  block  walls,  745. 

T-beams,   reinforced   concrete,   657,  659. 
Beam-footings,  steel,  58, 
Bearing,  Bearings, 

beams  and  girders,  295. 

lintels  and  caps,  279. 

stone  lintels,  289. 
steps,  293. 
templates,  295. 
Bearing-plate,  (see  base-plate). 
Bearing-stones,  295. 

Bearing  strength  (see  strength,  bearing). 
Bearing  wall, 

to  support  middle  of  area  steps,  114. 
Bed,  Beds, 

dressing  in  dimension  stone  piers,  303.  . 
footings,  brick,  92. 

heavy  buildings,  107. 
footing-stones,  90. 

irregular,  107. 
foundation,  of  gravel,  9. 

partly  on  rock,  partly  on  soil,  6. 
of  sand,  how  considered,  9. 
level,    rock    excavation,    foundations,  5, 
masonry,  264. 
stone,  backing,  300. 

sills,  301 
stonework,  hammer-dressed,  264. 
Bed-joints, 

ashlar  work,  267,  309. 
cut-stonework,  296. 
stone  tracery,  298. 
Bed-plate  (see  base-plate). 
Bed-rock, 

depth  at  site  of  Singer  building,  New 
York,  79. 

at  site  of  U.  S.  Express  building,  New 
York,  80. 

filled-in  fissures,  foundations,  6. 
Bee-hive  kilns,  319. 
Belgium,  Portland  cements,  164. 
Belgium,  Tournai,  Roman  cement,  144. 
Belt-courses,  275. 

ashlar  bond  and  support,  300. 

brick,  341,  342. 
washes,  341. 

bricks,  colored,  346. 

flashing  brick  with  lead,  342. 

measurement  of,  307. 

terra-cotta,   architectural,  835. 

washes,  276,  277. 
Bench-marks,  i. 

use  of,  in  staking  out  buildings,  2, 
Bending  moments, 

in  beams,  644,  645,  646,  648,  661. 

in  floor  slabs,  662. 

reinforced  concrete  design,  661,  662. 
slabs,  reinforced  concrete,  662. 
Berger  Manufacturing  Co.,  Canton,  Ohio, 
corrugated  steel  plate,  reinforcement,  514. 
prong-lock  metal  studs,  555. 
prong-lock  steel  furring,  571,  575, 


Berger   prong-lock   studs    (see    also  studs, 
Berger). 

Berger  steel  plate  concrete  floor  construc- 
tion (see  floors,  fire-proof). 
Best's  Keene's  cement,  807. 
Beton  Coignet,  260. 
Revelled  joints,  in  stonework,  274.. 
Bevier  patent  reinforced  tile  partition,  548. 
Bevier,  P.  H.,  ^  ^  . 

New  York  reinforced  tile  floor  arch,  489- 
Bins,  concrete,  reinforced,  636. 
Bituminous  concrete  (see  concrete,  bitumin- 
ous). 

Blackboards,  fastening  to  walls,  548. 
Block,  Blocks, 

concrete   (see  concrete  blocks). 

granite,  measurement  of,  306. . 

radial,  chimney  construction,  325. 

in-course  brick  bond,  381. 
Block-stones,  mortar  used  with.  97. 
Blue  clay,  foundations,  firm  soils,  7. 
Blue  shale,  248. 
Bluestone, 

production,   1896-1906,   205,  206. 

flagging,  modulus  of  rupture,  305. 
Blunt  piles,  27. 
Boards, 

batter,  i. 

fence,  2. 
Bologna,  Italy, 

San  Stefano,  Baptistry,  cornice,  345- 
Bolts,  drift   (see  drift-bolts). 
Bond. 

arches,  brick,  380. 

ashlar  work,  309. 

between  walls  of  different  heights,  302. 

bricks,  sand-lime,  332. 

brick  walls  at  angles,  359. 

brickwork.  349- 

concrete  block  walls,  863. 

mechanical,  concrete,  reinforced,  680. 

plumb,  coursed  ashlar,  295. 

cut-stonework,  300. 

gable  copings,  293. 

hollow  walls,  371- 

jamb-stones,  267. 

kneelers  of  gable  copings,  293. 

pier  stones  to  walls,  295. 

plumb  bond  in  regular  coursed  ashlar,  265. 

radial  block  chimney  construction,  325. 

rubble  stone  walls,  97. 

strength  of  walls,  97. 
Bond-stones,  294,  295.  ' 

specifications,  97. 

three-quarter  bond,  97. 

trimmings,  275. 
Bond-timbers,  364. 
Book-tiles,  roof  construction,  536. 
Borings,  test  for  character  of  original  soil, 

foundations,  4. 
Boston, 

building  laws,  regarding  piles,  33- 
subway,  entrance  at  Old  South  Meeting 

House,  124. 
Trinity  church,  loads  on  piles,  35. 
Bostwick,  perforated  sheet-metal  lath,  566, 
567,  568. 

Bostwick  Sheet  Lath  Co.,  Niles,  Ohio,  568. 
Boulders, 

bed  joints.  97. 

rubble  walls,  264. 
Box-anchors,  356,  357. 
Boxing,  cut-stonework,  301. 
Bracing  buildings,  118. 

inclined  braces,  126. 

spreading  braces,  125. 

trusses,  126. 
Breakwaters,  concrete,  595,  610. 


INDEX.  ^ 

Breast-^vall — Brick  Arches. 


919 


Breast-wall    (see   retaining-wall,  loi). 
Breweries, 

floor  arches,  segmental,  472. 

walls,  thickness  of,  910, 
Brick,  Bricks  (see  also  brickwork). 

absorptive  properties,  328. 

acids  of  atmosphere,  311. 

bays,  325. 

bevelled  in  belt-courses,  341. 
brittleness,  312,  324. 
burning,  318. 
cement,  334. 

cinders  in  manvifacture,  313. 
circle,  325,  339. 
circular  towers,  325. 
classification,  324. 
clay,  312. 

cohesive  strength,  317. 
color,  311,  312,  325. 
colored,  341,  346. 
common,  324,  336. 

modulus  of  rupture,  328. 

production,  value  of,  903,  905. 

specifications,  824. 
comparison   of   soft-mud    and  stiff-mud, 
317. 

composition,  311. 
curved,  339. 
dampness,  311. 
density,  317. 

deterioration  from  fi'ost,  88. 

from  saturation,  88. 
dry-clay,  315. 
drying,  318. 
dry-pressed,  316. 
durability,  311,  317. 
enamelled,  320. 

production,  value  of,  903,  905. 

size,  322. 
end-cut,  315. 
face  (see  face-bricks), 
fire  (see  fire-bricks), 
fire-clay,  hollow,  826. 
fire-proof  floors,  465. 
front,  production,  value  of,  903,  905. 
floor  arches,  kinds  used  in,  467. 
general  description,  311. 
glazed,  320. 

color,  321. 
hand-made,  313. 
hard-burned,  323,  324. 

durability,  underground,  88. 
hardness,  312. 
Haverstraw  size,  473. 
heat-resistance,  311,  441. 
heating  before  laying,  339,  340, 
hollow,  441,  826. 

floor  arches,  467. 
segmental,  473. 
interior  of  walls,  313. 
iron  oxide  in,  312. 
kinds  of,  311. 
laminated,  317. 
laying,  336. 

floor  arches,  467. 

in  freezing  weather,  339. 
machine-made,  313. 
magnesia,  312. 
manufacture,  313. 

capital  invested,  311. 
molded,  317,  325,  341,  342,  343,  344,  345. 

cornices,  342. 

specifications,  824. 

warped,  342. 
molds  for,  312. 
number  one,  320. 


ornamental,  325. 

production,  value  of,  903,  905. 
oxide  of  iron  in,  312. 
painting,  317. 
partitions  (see  partitions), 
paving,  322. 

annealing,  323. 

production,  value  of,  903,  905. 

strength,  crushing,  323. 
pitted,  313. 
porous,  31 1»  339- 

grouting  for,  337. 
pressed,  325. 
pressed,  clay  for,  313. 

color,  326. 

dry  process,  317. 

laying  dry,  339. 

sorting,  338. 

specifications,  824. 
qualities  of,  311,  312,  328. 
quicklime  in,  312. 
radial,  tile  fire-proof  columns,  449. 
radial  block,  387, 
raw,  313. 

red  or  well-burned,  319,  324. 
repressed,  317,  318,  325. 

paving  bricks,  322. 
Roman,  size,  327. 
roof  paving,  322. 
.salmon,  319,  324. 
sand  or  silica,  312. 
sand-lime,  261,  329. 

absorbtive  properties,  332. 

colors,  332. 

general  description,  329. 
heat-resistance,  332. 
manufacture,  329. 
modulus  of  rupture,  332. 
physical  characteristics,  332. 
production  in  1906,  333. 
quality,  331. 
strength,  crushing,  332. 
tests,  331. 

value  of  production  in  1903-1906,  333. 

sand-struck,  313. 

sawdust  in  manufacture,  313. 

shaky,  328. 

shape,  311,  312. 

shrinkage,  327. 

side-cut,  315. 

size,  275,  311,  326. 

slip  on  glazed  bricks,  320. 

slop-molded,  313. 

soft,  311. 

soft-mud,  314. 

specifications,  311. 

stiff-mud,  314. 

stock,  325. 

specifications,  824. 

strength,  312,  313,  326,  328. 
compressive,  317. 

substitute    for    concrete    in  water-proof 
basement  floors,  iii. 

tests  by  ringing  sound,  328,  331. 

texture,  312. 

use  of,  311. 

vitrified,  319,  326,  367. 

production,  value  of,  903,  905. 

warping,  312. 

weathering,  311. 

wetting,  339. 

weigth,  326. 

from  wetting,  339. 
Brick  and  concrete  construction,  621. 
Brick  and  stone  buildings  erected  in  Uni- 
ted States  in  1906,  901. 
Brick  arches  (see  arches,  brick). 


Q20 


INDEX. 


Brick  Backing' — Building  Laws. 


Brick  backing  (see  backing,  brick). 
]?rickbuilder,  The,  terra-cotta  details.  764. 
Brick  buildings,  stone  trimmings,  275. 
Brick  chimneys  (see  chimneys,  brick). 
Brick  construction  (see  construction,  brick). 
Brick  cornices  (see  cornices,  brick). 
Brick  facing. 

concrete,  860. 
walls,  703,  718. 
Brick  fireplaces  (see  fireplaces,  brick). 
Brick  footings,  91. 

bed  for,  92. 

bottom  course,  92. 

concrete  foundations,  93. 

coursing,  92. 

joints,  9T. 

mortar  for,  92. 

quality  of  bricks,  92. 

stepj)ing,  93. 
Brick  jambs,  for  rubble  walls,  264. 
Brick  lining,  basement  walls,  iii. 
Brick  nogging  (see  nogging,  brick). 
Brick  patterns,  341,  346. 
Brick  pavements   (see  pavements). 
Brick  piers   (see  piers). 
Brick  quoins,  for  rubble  walls,  264. 
Brick  stairs   (see  stairs,  brick). 
Brick  surface  patterns  (see  surface  patterns, 

brick). 
Brick  trimmings,  263. 
Brick  vaults  (see  vaults,  brick). 
Brick  veneer  (see  veneer,  brick). 
Brick  veneer  construction,  concrete  walls, 
718. 

Brick-veneered  walls,  concrete  block  walls, 

737.  7.38. 
Brick  walls,  wide  openings,  280. 
Brickwork   Csee  also  brick,  bricks). 

amount  of  cement  mortar  required  with 

difTerent  thicknesses  of  joints,  194. 
anchoring,  359. 

backing,  proportions  of  cement  and  sand 

in  mortar,  190.  « 
below  grade,  335. 
bond,  349. 

bond,  hoop-iron,  354. 
circular,  339. 
cleaning  down,  398. 

specifications,  830. 
climate,  effect  on,  340. 
color  affected  by  moisture,  340. 
columns,  311. 
common,  joints  in,  335. 

specifications,  825. 
cost  of,  311. 
cutting  and  fitting,  829. 
damp-proofing,  399. 
details,  miscellaneous,  379. 
diaper  work,  346,  347. 
drips,  340. 
dry  soils,  311. 
efflorescence,  541,  398. 
face,  proportions  of  cement  and  sand  in 

mortar,  190. 
first   class,    proportions   of   cement  and 

sand  in  mortar,  190. 
flashing  with  lead,  342. 
foundations,  311. 
frost,  effect  of,  328,  339. 
general  considerations,  335. 
grouting,  92. 

specifications,  827. 
joints,  335. 
laying,  336. 

in  freezing  weather,  831. 
lime  mortar  in  chimneys,  136. 
measurement  of,  402. 

for  stone  trimmings,  275. 


moistening  bricks  in  hot  weather,  197. 
moisture,  340. 
mortar,  826. 

colored,  199. 

joints,  thickness,  333. 

lime,  odinary  use  of,  136. 

natural  cements,  147. 

proportions  of  cement  and  sand.  189 
number  of  bricks  per  cubic  foot,  193. 
ornamental,  340. 

specifications,  825. 
piers,  311. 

pointing,  specifications,  830. 
pressed,  joints  in,  33b. 
projections  in,  341. 
protection  from  storms,  340. 

specifications,  825. 

while  building,  339,  340. 
specifications,  824. 
stains,  340,  341. 
strength,  335. 

crushing,  328,  401. 

effect  of  moisture  on,  340. 

transverse,  328. 
suggestions  in,  345. 
superintendence,  311,  403. 

ditlficulty  connected  with,  192. 
pressed,  sand  for  mortar,  132. 
surface  patterns,  347,  348,  349,  352,  353. 
weight,  906. 

wetting  bricks  before  laying,  93,  195,  339. 
wire  lath,  840. 
Bridges, 

arched,  Portland  cements,  use  in,  171. 

concrete,  595. 

reinforced  concrete,  635. 
Briquettes, 

cement,  strength  testing,  182. 
British   Fire   Prevention  Committee, 

tests  on  fire-proof  floors,  461. 
Brittleness, 

bricks,  312,  324. 
Broached  work, 

271,  272. 

Broken-ashlar  (see  ashlar,  broken). 
Broken  stone, 

with   concrete,   filled-in   rock   fissures,  6. 
Brown,    Alexander   E.,    ferroinclave  dove- 
tailed steel  sheets,  515. 
Brown,  Charles  C, 

cements  for  various  works,  171. 
estimate   on  quantities  of  cements,  etc., 
157. 

mortar  colors,  201. 
Brown  coat, 

plastering,  783. 
Brown  Hoisting  Mashinery  Co.,  Cleveland, 
Ohio., 

ferroinclave  partitions,  '559,  560. 
steel  sheets,  515. 
Brushes, 

bristle,  cleaning  stonework,  302. 

wire,  cleaning  stonework,  302, 
Buckling, 

brick  piers,  295. 
Bucks  or  frames,  for  doors, 

partitions,  tile,  548. 
Buffalo,  N.  Y.,  _ 

tests  for  bearing  power  of  piles,  34. 
Business  blocks  (see  buildings,  office). 
Building  codes  (see  building  laws). 
Building  laws,  11, 

bond-stones,  294. 

concrete  block  construction,  746. 
building  blocks,  862. 

footings,  concrete,  88. 

foundations,  11,  15,  16. 
walls,  thickness  of,  100. 


INDEX. 


921 


Building:  Lines — Ceilings. 


lime  mortar,  136. 

New  York  requirements,  130. 
masonry,  loads  on,  303. 
party  lines,   foundations,  83. 
piles,  Boston  requirements,  33. 
Chicago  requirements,  33. 
New  York  requirements,  33. 
Philadelphia  requirements,  33. 
reinforced  concrete,  allowable  stress,  50. 
sand-lime  bricks,  332. 
soils,  safe  bearing  strength,  11. 
vaults  under  sidewalks,  115. 
Building  lines, 

staking  out  city  buildings,  3. 
Building  materials, 

processes  of  manufacture,  145. 
Building  operations  in  leading  cities  of  the 
United  States,  in   1905  and  1906,  900. 
Building  ordinances  (see  building  laws). 
Building  permits  in  United  States  in  1906, 
901. 

Building  regulations  (see  building  laws). 
Jiuildings, 

brick  and  stone  in  United  States  in  1906, 
901. 

character  of,  erected  in  leading  cities  of 

United  States  in  1906,  901. 
cost  of,  in  leading  cities  of  the  United 
States,  in  1905  and  1906,  900. 

of,  in  United  States  in  1906,  901. 
fire-proof,  cost,  average,  in   1906,  902, 
granite,  lists  of,  S«7,  66g,  890. 
heavy,  built  on  gravel  foundations,  9. 

Colorado,  footings,  how  laid,  8. 
high,  cut-stonework,  298. 
isolated,  designing  foundations,  13. 
Jight,  foundations,  3. 
limestone,  lists  of,  887,  889,  890. 
marble,  lists  of,  888,  889,  890. 
office  (see  office-builduigs; . 
on  rock,  foundations,  6. 
public,  drawings  for  cut-stone,  295. 
sandstone,  lists  of,  888,  889,  890. 
stone,  lists  of,  887,  889,  890. 
wood,  erected  in  United  States  in  1906. 
901. 

J]uilt-up  stone  arches,  284,  289. 
J3uilt-up  .stone  lintels,  289. 
Bumpers,  jamb  protectors,  769. 
Burning  bricks,  318. 

Bush-hammer,  for  stone  dressing,  270,  271. 

Bush-hammered  work,  273,  274. 

Butler,  David  B.,  Portland  cements,  color, 

172. 
Buttresses. 

area  walls,  stiffening,  106. 
concrete  blocks,  864. 
Byrne,  Austin  T.,  Portland  cements,  color 
of,  172. 

C 

Cabot's  brick  preservative,  400. 
Caissons, 

boulders,  78. 

classes  of,  74. 

construction  of,  in  ^Manhattan  Life  Ins. 

Co.'s  Bldg.,  N.  Y.,  79. 
deflection  in  sinking,  78. 
erect,  74. 
filling,  75. 
inverted,  74. 

bracing,  74. 
[Manhattan  Life  Ins.  Co.'s  Bldg.,  N.  Y. 
75- 

materials,  74. 

Moran  air-lock,  principles,  82, 
open,  74. 

plenum  system,  75. 


admission  of  workmen,  75, 
air-lock.  75. 

disposal  of  excavated  material,  75. 
shapes,  74. 
sinking,  74. 
stepping  off  rock,  78. 

sunk  to  hard-pan  through  mud,  founda- 
tions, 9. 

time  of  sinking,  78. 

vacuum  system,  74. 
Caisson  foundations,  general  description,  74. 
California,   South   Riverside,   hydraulic  ce- 
ment analysis,  145. 
Calcium  silicate,  bricks,  sand-lime,  330. 
Cambering,  floor  arches,  tile,  468. 
Canadian  Society  of  Civil  Engineers, 

fineness  of  Portland  cements,  175. 
Canals,  New  York  State, 

specifications  for  natural  cement,  844. 
for  Portland  cements,  848. 
Cantilever  beams, 

concrete,  reinforced,  635. 
Cantilever  foundation  construction, 

anchoring  with  excessive  leverage,  86, 

bed-plate,  85. 

built-up   plate  girder,  85. 
footings,  84. 

girders,   stiffening-angles,  86. 
grillage  beams,  85. 
headroom  in  basement,  85. 
reducing  cost  by  use  of  reinforced  con- 
crete, 86. 
relative  cost,  86. 
stability,  conditions,  84. 
support  of  girder  by  column,  86. 
Cap,  Caps, 

chimney,  cast-iron,  770. 
concrete  block  construction,  864. 
concrete,  reinforced,  742,  864. 
stone,  267,  277,  279. 

building  ends  into  walls,  278,  279. 
strength  of,  305. 
columns,  291. 
window,  terra-cotta,  architectural.  835. 
Capitals,   stone,   washes,  276. 
Capitol,    Albany,    N.    Y.,    quality    of  soil 

under,  11. 
Capping, 

grillage    (see  grillage   capping,  38). 
piles,  818. 

best  arrangements,  37. 
concrete,  37. 

with  embedded  rods,  38. 
number    of    piles    supporting  capping 

stones,  36. 
wooden,  36. 
Carbonates,  slates,  amount  of  carbonates  in, 

895,  896. 
Carborundum,  flooring,  534. 
Carthagenians,  early  use  of  cements,  141. 
Carton-pierre,  797. 
Carving, 

bricks,  sand-lime,  332, 
stone,  cleaning,  302. 

estimating  cost  of,  307. 
door   and   window  tile,   molded,  hollow. 

Cast-iron  arch-girders  (see  arch-girders) 

Cast-iron,  fire-resistance,  446. 

Caustic  lime  (see  lime,  common,  127). 

Cast-iron,   in  foundations,  coating,  96. 

Ceiling  tiles,  539,  540. 

Ceilings, 

suspended,  air-spaces,  539. 
fire-proof  buildings,  539. 
metal  lath  and  plaster,  540. 
tile,  539. 
tile  fire-proof  floor  arches,  470. 


922 


INDEX. 


Cellars — Cement. 


vaulted,  495. 

terra  cotta,  430,  431. 
Cellars,  draining,  24. 
Cellar  walls   (see  walls,  foundation). 
Cement,  Cements  (see  also  cements,  natu- 
ral, Portland,  etc.). 

analysis  of,  table,  140. 

barrels,  average  sizes  of,  157. 

brands,  selection  of,  159. 

carload  lots,  158. 

cheaper  brands,  economy  in,  160. 

choice  of,  159. 

classification,  139. 

cloth  bags,  returning,  159. 

color  of,  as  affecting  concrete  blocks,  744. 

coloring  matter,  199. 

concrete  blocks,  864. 

constancy  of  volume,  674. 

consumption  in  1906,  877. 

exports  in  1900-1906,  877. 

exterior  work,  171. 

imports  compared   with   production  and 

consumption,  876. 
imports  in  1901-1906,  875. 
kinds   used  in   reinforced  construction, 

674.  .  , 

lime  mortar  mixed,  335. 
matrix,  594. 

mortar,  natural  (see  mortar,  natural  ce- 
ment). 

mortar,  Portland  (see  mortar,  Portland 
cement). 

packages,  cloth  and  paper  bags,  158. 
plaster  (see  plaster). 

plastered  on  outside  walls,  foundations, 

clay  soils,  8. 
quality  in  reinforced  work,  849. 
quantities,  estimates  of,  157. 
setting,  time  required  for,  674. 
setting  under  water,  189. 
sand  in  Portland  cement,  169. 
sidewalks,  utility  and  durability,  114. 
soundness,  674. 
special  tests,  153. 
storage,  849. 

strength  of  mortars,  compressive,  186. 
tensile,  185. 
tensile,  table,  186. 
tests,  182. 

adhesive,   182,  187. 
briquettes,  182. 
form,  183. 
molds  for,  183. 
storing,  184. 
clips,  to  hold  briquettes,  183. 
compression,  182,  186. 
concrete  blocks,  864. 
flexural,  182,  187. 
machines,  184. 

simple   testing,  184. 
mixing,  methods  of,  184. 
mixtures,  182. 
neat  cement,  182. 
object  of,  182. 
Portland  cements,  182. 
rate  of  applying  load,  185. 
reinforced  concrete  work,  849. 
shearing,   182,  187. 
Taylor,  W.  Purves,  150. 
tensile,  182. 
transverse,  187. 
with  sand,  185. 
suitability  to  work,  171. 
use  of,  determined  by  economy,  171. 
weight  per  cubic  foot,  156. 
Cement,  European,  classes  of,  143. 
Cement,  hydraulic,  i.^q. 

imports  into  the  United  States  in  1903- 


1906,  by  countries,  874. 
Cement,  Keene's,  795. 

non-hydraulic   cement,  139. 

trim,  interior,  fire-proof  buildings,  578. 
Cement,  Lafarge,  pointing  stonework,  302. 

(see  also  limes,  hydraulic). 

setting,  cut-stonework,  301. 
Cement,  natural,   139.   (See  also  cements). 

accelerated  test  for  soundness,  150. 

activity,  or  time  of  setting,  149. 

American  and  European,  Prof.  J.  B. 
Johnston,  144. 

analysis  of,  table,  145. 

average  size  of  barrels,  157. 

burning,   145,  146. 

carbon  dioxide,  140. 

checking,  151. 

chemical  analysis,  American,  144. 
color,  148. 

comparison    of    setting    with    that  of 

Portland  cement,  150. 
competition  with  Portland  cement,  141. 
cracking,  151. 
crushing,  146. 
definition  of,  140. 
deformation,  150. 
disintegration,  151. 
distortion,  151. 

distribution  in  United  States,  141. 
early  use,  141. 

economy   of    use   compared   with  that 
of  Portland  cement,  159. 

Edwin    C.    Eckel,    regarding   shale  at 
Defiance,  Ohio,  143. 

effects  of  grinding,  151. 

European,  143. 

competition    with    Portland  cement 
and  hydraulic  lime,  143. 

dimensions  of  barrels,  156. 

field  inspection,  148. 

final   set,  149. 

fineness,   151,  844,  846. 

first  in  United  States,  141. 

fuel  for  burning  limestone,  146. 

grinding,  140,  145,  146. 

hardening  of,  in  air  or  water,  140. 

hydraulic,  139. 

hydraulicity,  140. 

initial  set,  149. 

kilns,  146. 

localities  of  manufacture  arranged  by 

States,  142. 
loss  by  non-uniform  burning,  146. 
Madison  Co.,  New  York,  141. 
manufacture  of,  145. 
manufacture,    breaking    and,  crushing 

rock,  146. 
layers  of  rock  and  fuel,  146. 
quarrying  rock,  146. 
market  area  of  different  brands,  161. 
miscellaneous  data,  156. 
mixed  with  lime  mortar,  147. 
mixed  with  Portland  cement,  Taylor  & 

Thompson,  147. 
mixture  for  concrete,  88. 
mortar   (see  mortar,   natural  cement), 
mortar,  freezing,  147. 
non-hydraulic,  139. 
non-slaking,  140. 

non-uniformity  of  hardening,  148. 
normal  test  for  soundness,  150. 
packages,  148. 
packing,  147. 

produced  by  John  Smeaton,  141. 
production,  141. 

comparison    with    that    of  Portland 
cement   in    1901-1906,  ,  875. 


INDEX. 


9^3 


Cement,  Portland. 


in  1904,   1905  and  1906  by  States, 
870. 

properties,  148. 

proportions  of  sand  in  mortar,  159,  189. 
quality  due  to  manufacture,  142. 
ratio  of  compressive  to  tensile  strength, 
186. 

requirements,  148. 
Roman   cements,  141. 
European,  143. 
composition,  144. 
%     setting  of,  144. 
Strength,  144. 

with  sand,  144. 
weight  per  cubic  foot,  156. 
sampling,  148. 
screening,  146. 
setting,  140. 

time  required,  846. 
soundness,  845. 

tests  for,  150. 
specific,  gravity,  effect  of  burning  on, 
149. 

specifications,  154,  844. 

Engineer  Corps,  U.  S.  Army,  1901, 
845. 

New  York  state  canals,  1896,  844. 
Rapid-Transit    Subway,    New  York 
City,   1 900- 1 90 1,  844. 
staining  stonework,  138. 
storage  in  damp  places,  148. 
strata  of  limestone,  146. 
strength  depending  upon  fineness,  151. 
required    by    various  specifications 

table,  153. 
tensile,  186,  844,  846. 
tests,  152, 
substitution  for  lime  in  mortar,  147. 

for  Portland  cements,  147. 
temperature,  burning,  140,  146. 
testing  hardening  of,  150. 

mixed  lots,  148. 
uniformity,  147. 
unsoundness,  cause  of,  150. 
use  of,  141,  147. 

in  mortars,  188. 
variety  of  products,  i6r. 
volume,  constancy  of,  150. 
weight,  845,  846. 
per  bag,  157. 
per  barrel,   156,  157. 

in  different  localities,  149. 
per  cubic  foot,  149,  156. 
Cement,  Portlands  (see  also  cements), 
activity  or  time  of  setting,  173. 
alkali  waste  and  clay,  166. 
American  made,  specifications,  163. 

weight,  per  cubic  foot,  156. 
anhydrous     sulphuric     acid,  reinforced 

■  work,  850. 
artificial  stone,  163. 

barrels,  weights,  measures  and  contents, 
179. 

brands,  choice  of  and  selection  of,  ,179. 
calcining,  167. 

character  of  materials,  table,  165. 
checking,  cracking,  174. 
chemical  analysis  of,  165. 
classification,  place  in,  139,  161. 

composition  affecting  color,  171. 
coefficient  of  elasticity,  188. 
color,  171. 

affected  by  everburning,  171. 
color,  ingredients  affecting,  171. 
composition  of  a  good  cement,  167. 
cooling  after  calcining,  167. 
composition,  uniform,  170. 


concrete  blocks,  730,  865. 

construction,    revolution    in  engineering 

and  architectural,  164. 
consumption,   compared  with  production 

and  imports  in  1891,  1904,  1905  and 

1906,  876. 
crushing  materials,  167. 
damp-proof  courses,  367. 
definitions  of,  161. 
disintegration,  174. 
distortion,  174. 
drying  before  grinding,  167. 
dry  process  of  manufacture,  descriptiort 

of,  168. 

early  history  and  use  of,  163. 
economy,    comparison    with    natural  ce- 
ments, 159. 
English,  strength  of,  with  different  pro- 
portions of  cement  and  sand  in  mar- 
tar,  191. 
weight  per  cubic  foot,  156. 
exposure  to  elements,  170. 
field  inspection,  171.  ' 
fineness,  174,  848. 

in  reinforced  work,  849. 
French,  weight  per  cubic  foot,  156. 
fuel  vsed  in  rotary  kilns,  168. 
fusion,  161. 

German,  weight  per  cubic  foot,  156. 
grinding,  167.  ' 

after  calcining,  167. 

machinery,  167. 
hot  test,  174. 

improvement  in  quality,  164. 
in  contact  with  water,  170. 
industry,  development  of,  163. 
industry,  development  of,  since  1890,  873- 
geographic  distribution  of,  in  1905  and 
1906,  871. 
kilns,  rotary,  description  of,  168. 
stationary  and  rotary,  167. 

intermittant  and  continuous,  167. 
limestones  used,  166. 
limestones  and  clays,  shales,  166. 
manufacture,    rapidity    of  development^ 
164. 

miscellaneous  data  and  memoranda,  179. 
mixing,  wet  and  dry  processes,  167. 
mixture  for  bedding  beams,  58. 

for  concrete,  88. 
mortar  for  piers  and  arches,  188. 
natural  Portlands,  European,  143. 

European  manufacture,  144. 

comparison  with  true  Portland  cements, 
144. 

rank,    compared   with   true  Portlands, 
163. 

neat  cement,  strength  tests,  176. 
origin  of  name  on  account  of  color,  172. 
packages,  171. 
packing,  167. 

place  in  classification,  161. 
production,  comparison  of  domestic,  with 
consumption    of    cements    in  1891, 
1904,  1905  and  1906,  876. 
comparison  with  that  of  natural  cement 

in  1901-1906,  875. 
in  1904-1906,  by  states,  872. 
production,  variety  in  methods,  167. 
present  use,  164. 
process  of  manufacture,  167. 
proportions  of  mixture,  165. 

of  sand  in  mortar,  159,  189. 
properties,  characteristic,  171. 
quality  not  indicated  by  color,  171. 
ratio  of  compressive  to  tensile  strengths, 
186. 


INDEX. 


Cement,  Puaissolan — Chemieal  Composition. 


of  lime  to  other  ingredients,  162. 
raw  materials  available,  165. 
raw  materials,  localities  and  varieties  of, 
166. 

references   to  literature   on  constitution 

of,  167. 
requirements,  171. 
sampling,  171. 

set,  in  reinforced  work,  849. 

setting,  time  of,  compared  with  that  for 
natural  cements,  173- 

setting,  comparison  with  natural  ce- 
ments, 150. 

sidewalks,  117. 

silicates  in,  330. 

slag,  166. 

soundness,  or  constancy  of  volume,  173. 
848. 

importance  of  tests,  173. 

in  reinforced  concrete  work,  849. 
specific  gravity,  162,  173. 

in  reinforced  work,  849. 
specifications,  176,  847. 

for  acceptance,  177. 

for  definition  of  cement,  177. 

for  fineness,  177. 

for  J^Jew  York  State  canals,  1896,  848. 
for^apid  Transit  subway,  New  York 

City,   1900-1901,  848. 
for  requirements,  177. 
for  sampling,  177. 
for  setting  time  of,  178, 
for  soundness,  178. 
for  specific  gravity,  177. 
for  sulphuric  acid  and  magnesia,  178. 
for  tensile  strength,  178. 
for  tests,  177. 
for  weight,  177. 
for  packages,  177. 
staining  stonework,  138. 
strength,  170. 

increased  by  addition  of  sugar,  197. 
tensile,  848. 

reinforced  work,  850. 
table,  186. 
tests,  175. 
typical  method  of  manufacture,  168. 
use,  170. 

in  damp-proofing,  109. 
under  water,  188. 
value  in  comparison  with  other  cements, 

170. 
.  weight,  172. 

depending  upon  age,  172. 
upon    burning,  172. 
upon    fineness,  172. 
per  bag,  157. 
per  barrel,  156,  157, 
per  cubic  foot,  172. 
wet  process  of  manufacture,  description, 
169. 

description  of  vat  or  wash  mill,  169. 
with  rotary  kilns,  169. 
widening  field  of  application,  170. 
with  hydrated  lime,  131. 
with  natural  cements,   quick-setting  with 
great  strength  mixture,  148. 
Cement,  Puzzolan,  179. 
activity,  181. 

characteristics  and  properties,  181. 
chemical  analysis,  180. 
classification,  179. 
color,  181. 
definition,  179. 
disintegration,  181. 
effect  of  mechanical  wear,  181. 
exposure  to  dry  air,  181. 
to  moisture,  180, 


fineness,  182. 

for  white  mortars,  202. 

hardness,  180. 

in  underground  work,  181, 

manufacture,  180. 

materials,   artificial,  180. 

materials,  natural,  180. 

mechanical  mixture,  179. 

non-staining,   138,  181. 

production  (see  cements,  slag). 

setting,  181. 

soundness  and  constancy  of  volume,  <(8i. 

specific  gravity,  181. 
specifications,  182. 
strength,  182. 

ratio  of  compressive  to  tensile,  186. 
tensile,  186. 
toughness  and  non-brittleness,  180. 
uses  of,  180. 
weight,  181. 
Cement,  selenetic;  Scott's  cement,  197. 
Cement,  silica-portland,  169. 
effect  of  moisture  on,  170. 
introduction  of  process,  170. 
mixture  with  sand,  169. 
Cement,  slag  (see  also  cement,  Puzzolan). 
production   in   1904- 1906   by   States,  874 

(see  also  cement,  Puzzolan). 
weight  of,  gross  and  net,  158. 
Cement,  white,  English,  201. 
Cement  blocks  (see  concrete  blocks). 
Cement  bricks  (see  bricks,  cement). 
Cement-brick  backing,  concrete  block  walls, 

742,  743- 
Cement  flooring,  533,  860. 
Cement  floor  surface,  472. 
Cement  grout,  filling  hollow  concrete  block 

columns,  699. 
Cement-lime  mortars  (see  mortars). 
Cement  mortars  (see  mortars,  cement). 
Cement  pavements,  861. 
Cement  plaster,  non-hydraulic,  139. 
Cement  walks,  117. 
covering,  118. 
durability,  117. 
finishing,  117. 

coat  application,  117. 
foundation,  117. 
levelling,  118. 
mixture  of  concrete,  117. 
tamping  concrete,  117. 
Cementing  outside  of  walls,  specifications, 
820. 

Cements,  limes  and  mortars,  127. 
Centering, 

concrete-and-tile  systems  of  floor  construc- 
tion, 713. 

concrete,  reinforced,  specification,  851. 
floor  arches,  tile,  468. 
Center  of  base,  20. 

Center  of  gravity,  weight,  foundations,  20. 

Center  of  pressure,  19. 

Centers, 

arches  and  vaults  of  brick,  338. 

floor  arches,  segmental  tile,  476. 

wood,  stone  arches,  289,  290,  291. 
Chair-rails,    grounds    for,    on  metal-and- 

plaster  partitions,  557,  558. 
Channel-block  metal  wall  furring,  571,  572. 
Chemical  changes, 

lime  burning,  128. 

slaking  lime,  129. 

probable  action  between  lime  and  sand  in 

setting  of  mortar,  133. 
setting  of  lime  mortar,  according  to  Mr. 
C.  F.  Mitchell,  134. 
Chemical  composition, 
cements,   Portland,  165. 


INDEX. 


925 


Chemical  Pla 

pranites,  884.  I 
limestones.  885. 

marbles,  885.  ' 
onyx  marbles,  886.  ! 
sandstones,  884.  | 
slates,  886. 
stones,  884. 
Chemical  plaster  (see  plaster). 
Chicaro,  111., 

building  law,  33. 

regarding  foundations,   11,  15, 
griilaee  capping  for  piles,  38. 
Illinois    Central    Railroad    Station,  piles 

supporting,  27. 
N.   Y.   Life  buildinp-,   foundations  under 

old  wall  of  adjoining  building,  123. 
Northern   Pacific   Railroad   Station,  load 

on  piles,  35. 
pile   foundations   under  grain  elevators, 

35-  . 

Public   Library   building,   load   on  piles, 

piling,  34. 
Rand-McNally  building,   footings,  59. 
Schiller  building,  load  on  piles,  35. 
Stock  Exchange  building,  masonry  wells, 
72-. 

supporting  power  of  soil,  25. 
timber  footings,  68. 
underlying  soil,  25. 

use  of  railroad  rails  in  spread  footings, 
59. 

World's  Fair  buildings,  foundations  of  71. 
Chimneys, 

brick,  383. 

specifications,  828. 

cements,  Portland,  use  of,  170. 

concrete,  595. 
reinforced,  636. 

fire-brick  lining,  324. 

radial  blocks,  325. 

salmon  brick  lined,  324. 

strength,  325. 
Chisels  for  stone  dressing,  271. 
Churches, 

computing  weight  on  footings,  16. 

walls,  thickness  of,  910. 
Cinders, 

brick  manufacture,  313. 

concrete  blocks,  730. 

in  concrete,  stains  on  plaster,  cause  of, 
469. 

Circle  bricks,  325,  339, 
Circular  stairs,  294. 
City  buildings,  3. 

depth  of  foundations,  14. 

staking  out,  3. 
City  ordinances  (see  building  laws). 
Clamps, 

ashlar,  300. 

coping  stones,  293. 

stone  entablatures,  292. 

stonework,  823. 

trying  stone  voussoirs,  284,  285. 

iron,  stone  columns,  292. 
Clark,  Addison  H.,  strength  of  mixture  of 

silica-cement  and  sand,  170. 
Clay, 

Clay,  ball  (see  ball-clay), 
brick  manufacture,  311. 

mining  for,  313. 
flint,  fire-brick,  324. 
foundations,  4. 

with  stone  drains,  8.  * 
freezing  to  outside  of  foundation  walls, 

prevention  of,  8. 
heavy  blue,  firm  soils,  7. 
mining,  for  bricks,  316. 


ster — Color. 

plastic,  for  fire-brick,  324. 

pressed  bricks,  313. 

safe  bearing  strength,  10. 

sand-lime  bricks,  331. 

shale  clay  in  brick  making,  322. 

terra-cotta,  architectural,  405. 

with  sand  or  gravel,  foundations,  8. 
supporting  power  of,  foundations,  8. 
Clay  pits,  brick  making,  314. 
Clay  products,  value  of,  in  United  States 

in   1905  and  1906,  903. 
Clay  slates,  898,  899. 
Clay  soils, 

adjacent  excavations,  7. 

bearing  power,  7. 

danger  when  wet,  foundations,  7. 

effect  of  freezing  and  thawing,  7. 

footings,  7. 

heavy  buildings,  7. 

pressure  of  walls  on,  7. 
,  shale,  7. 

slate,  7. 

sub-soil  drains,  7. 
water  excluded,  7. 
Clay  wares,  burning  in  kilns,  319. 
Cleaning, 

brickware,  398,  830. 
cut-stonework,  302. 
stonework,  824. 

compressed  air,  302. 
sand-blast,  302. 
steam,  302. 
terra-cotta.  architectural,  836. 
Cleavage,  slates,  803,  894. 
Climate,  stones,  effect  on,  250. 
Clincher   perforated   sheet-metal   lath,  567, 
S68. 

Clinton  Wire  Cloth  Company,  454,  456,  458. 

welded  metal  fabric  reinforcement,  523. 
Clinton  wire  fabric  for  reinforcing  concrete, 
•15- 

Clinton  wire  lath,  t;6i.  c;62,  563. 
Clips  for  suspended  ceilings, 

Streeter,  540. 

White,  540,  541. 
Club-houses,  walls,  thickness  of,  908. 
Coal,  brick  manvifacture,  311. 
Coal-dust,  brick  manufacture,  314. 
Coal  hole  covers  and  frames,  771. 
Coal-tar,  use  of  in  damp-proofing,  no. 
Coating  for  cast-iron  work  in  foundations, 
96. 

Coating  outside  of  walls,  109. 
Cobble  stones,  97. 
Coefficient  of  expansion, 

concrete,  601. 

steel,  679. 

Coefficient   of   elasticity    (see   modulus  of 

elasticity). 
Codes,  building  (see  building  laws). 
Cohesion, 

brick  materials,  317. 

bricks,  312. 
Cold-air  duct,  specification,  828. 
Cold-twisted  lug  bar   (see   concrete,  rein- 
forced). 
Color, 

aggregates  for  cement  bricks,  334. 
bricks,  311,  312,  324,  325, 

glazed,  321. 

pressed,  338. 

sand-lime,  332. 
cement  in  concrete  blocks,  744. 
clay  for  pressed  bricks,  313. 
concrete  blocks,  744. 
mineral,  for  lime  mortar,  133. 
mortar  (see  mortar  colors), 
plaster,  exterior,  798, 


926 


INDEX, 


Colorado — 

sand  finish,  809. 
sand  in  concrete  blocks,  744. 
sandstones,  308. 
slates,  243,  893,  894. 

stone  screenings  in  concrete  blocks,  744. 
stones  for  building,  254. 
terra-cotta,  architectural,  408. 
Colorado, 

bedding  of  pavement  stones,  116. 
nature  of  soil,  foundations,  8. 
top  soil,  of  what  composed,  foundations, 
8. 

Colored  mortar  (see  mortar,  colored). 
Columbia   University,   tests,   bricks,  sand- 
lime,  332. 

Columbian  concrete  floor  construction  (see 
also  floors,  fire-proof,  and  concrete,  re- 
inforced). 

Columbian  Fire-proofing  Co.,  Pittsburg,  Pa., 
concrete,  reinforced,  type  of  construction, 

704,  706. 
floor  construction,  506. 

Columbian  flat  concrete  floor  construction, 
different  systems,  506,  507,  508,  509, 
510. 

Columbian  system  (see  floors,  fire-proof  and 

concrete,  reinforced). 
Column,  Columns, 

box  concrete  covering,  453. 

tile  covering,  450. 
brickwork  in,  311. 
cast-iron,  667. 

heat-resistance,  447,  448. 
Concrete  block,  698. 
Concrete,  reinforced,  667,  695. 

American   Steel   and  Wire  Company's 

system,  697. 
bases  of,  717. 

Cummings  hooped  columns,  696,  704, 

705,  706. 
examples  of,  670. 
Hennebique  reinforcement,  695. 
hooped  reinforcement,  672,  673. 
hooping  and  spacing  bars,  696,  697,  705, 

706. 

Hinchman-Renton   system  of  reinforc- 
ing, 697. 

Kahn  trussed  bar  reinforcement,  699. 
loads  on,  717. 

longitudinal  reinforcement,  amount  and 

disposition  of,  671. 
longitudinally,  strength  of,  668. 
structural  steel  core,  719. 
wrapped  reinforcement,  672,  673. 
T.  I.  M.  patent  column,  701,  702. 
false,  steel  and  concrete,  456,  458. 
fire-proofing,  447, 

allunited  furring,  454. 
composition-block,  459. 
concrete,  451. 

and  plaster  on  wire  lath,  434,  455, 
.      456,  457. 
Fair_  building,  Chicago,  111.,  471,  472. 
gypsite  tile  covering,  459. 
Hennebique  system,  453. 
Hinchman-Renton  system,  452,  453,  455, 
4S6. 

"Ideal,"  tile,  449. 
lath-and-plaster,  451,  454.- 
plaster,  454. 
plaster-block,  459. 
Rapp  Fire-proofing  Co.,  456,  457. 
Roebling  Construction  Co.,  456. 
specifications,  832. 

Standard  Concrete  Steel  Co.,  concrete 

blocks,  458,  459. 
tile,  449. 


■Concicte. 

White  Fire-proof  Construction  Co.,  456, 
457- 

footings    "New    York    Times"  building, 
foundations,  6. 
reinforced  concrete,  50. 

example,  54. 
spread,   reinforced  concrete,  52. 
ftirred  and  wire-lathed,  841. 
oak,  667. 
pine,  yellow,  667. 

white,  667. 
sizes  reqvtired  for  different  materials  to 

support  same  load,  667. 
spruce,  667. 
steel,  667. 

heat-resistance,  447,  448. 
structural,   concrete-incased,  719. 
on  rock  foundations,  6. 
stone,  291. 
cracks,  310. 
loads,  safe,  305. 
setting,  310. 
strength,  304. 
strength  of  wrapped  or  hooped  reinforced 

concrete,  672. 
terra-cotta,   architectural,  414,  415,  419. 
420. 

wall,  skeleton  construction,  768. 
wrought-iron,  fire-resistance,  447. 
Z-bar,  concrete  covering,  453,  455. 
tile  covering,  450. 
Combination  tile  floor  arch,  477. 
Combined  footings,  steel  beam,  67. 
Common  bricks  (see  bricks,  common). 
Common  lime  (see  lime,  common). 
Compacting  soil,  by  driving  piles,  26. 
Composite    concrete    and    structural  steel 

system  (see  concrete,  reinforced). 
Composite  piles,  concrete  piles  in  conjuc- 

tion  with  timber  piles,  44. 
Composite  stone  lintels,  279. 
Composition-block,    fire-proofing,  columns, 

459;  , 

Composition  of  bricks,  311. 
Composition  of  soils,  foundations,  4. 
Compressed  air,  cleaning  stonework,  302. 
Compressible  soils, 

footings  for  heavy  walls  on,  93. 
foundations  on,  25. 
location,  25. 
Compression, 

joints  in  masonry,  278. 
mortar  joints,  303. 
soil  in  trenches,  by  ramming,  24. 
Compression    rods,    concrete    beams,  rein- 
forced, 665. 
Compressive   strength    (see  strength,  com- 
pressive). 

Compressol  system,  concrete  piles,  45. 
Concave  joints,  stonework,  302. 
Concrete  (see  also  concrete,  reinforced), 
adhesion  to  steel,  660. 
aggregate,  594. 

amount  obtained  with  different  mixtures, 
194. 

availability,  87. 

basement     floors,     thickness  depending 
upon  outside  water  level,  iii. 
watertight,  110. 
beam  protection,  533. 
cement,  natural,  148. 

Portland,  170,  188. 
cement  bricks,  proportions  for,  334. 
cinders  in,  cause  of  plaster  staining,  469. 
coefiicient  of  expansion,  601. 
coloring  matter,  199. 
composition,  499. 
compressive  resistance,  52. 


INDEX. 

Concrete,  Bituminous — Concrete,  Reinforced. 


concrete  blocks,  730. 

conductivity,  723. 

consistency,  676. 

contraction  in  hardening,  602. 

cost,  604. 

definitions,  594. 

depositing,  598. 

in  layers,  58. 

reinforced  in  footings,  52. 
direct  compressive  stress  allowed,  660. 
early  use,  594. 
elastic  limit,  601. 
examples  in  building,  607. 
expansion  in  hardening,  602. 
filling  depressions,   rock  excavations,  5. 
fire-proofing,  columns,  449. 
forms  for,  in  compressible  soils,  58. 
girder  protection,  533. 
handling,  miscellaneous  data,  606. 
hardening,  602. 
heat-resistance,  445,  603. 
kinds  used  for  concrete  blocks,  730. 

used   in   reinforced  construction,  674. 
laying  in  freezing  weather,  602. 
loads  on,  safe,  907. 

working,  599. 
machinery  for  mixing,  597. 
materials,  proportions  of,  596. 

selection   of,  595. 
matrix,  594. 
mixing,  597. 

mixtures,    caisson   construction,  Manhat- 
tan Life  Ins.  Co.'s  Bldg.,  N,  Y.,  78. 

cement  sidewalks,  117. 

different  kinds  of  work,  596. 

filling  between  grillage  beams,  58. 

footings,  88. 

reinforced  work,  52. 

Simplex  concrete  piles,  48. 

steel  beam  footings,  58. 

superintendence  of,  106. 
modulus  of  elasticity,  600,  601,  660. 
placing,  598. 

preventing  rot  in  wooden  piles,  37. 
properties  of,  in  combination  with  steel, 
679. 

proportions  for  concrete  blocks,  730. 
protection  to   steel  beams,  59. 
quantities  required  per  cubic  yard,  625. 
rammed,   for  filled-in  rock  fissures,  6. 
sea  water,  effect  of,  603. 
setting,  602. 
shrinkage  cracks,  602. 
stone,  heat-resistance,  445. 
strength,  598. 

compressive,  599,  600. 

crushing,  598. 

reinforced   construction,  676. 

shearing,  600. 

tensile,  599. 

transverse,  87. 
submarine  use,  595. 
tension,  diagonal,  601. 
specifications,  607. 

for  laying  in  freezing  weather,  602. 
thickness  of  layers,  88. 
use  in  rock  excavation,  foundations,  5. 
_  footings,  "New  York  Times"  building, 

rock  foundations,  6. 
present  uses,  594. 
water,  effect  of,  107. 
weight,  606. 
Concrete,  bituminous,  594. 
Concrete,  cinder, 
corrosion,  446. 

of  reinforcements,  725,  726. 
filling  on   fire-proof  floor  arches,  471. 

in  reinforced  work,  861. 


heat-resistance,  446,  723. 
modulus  of  elasticity,  601. 
partitions,  542. 

slabs,  constants  used  in  formulas,  656. 
strength,  723. 

compressive,  601. 
sulphur  in,  726. 
Concrete,  mass, 
cellar  walls,  622. 
cost,  610. 

depositing  under  water,  610. 
examples,  early,  608. 
forms,  611. 

examples  of,  613. 
foundations  for  light  buildings,  622. 
materials,  610. 

depositing,  610. 

mixing,  610. 
molds,  611. 
proportions,  610. 
uses,  early,  608.' 
Concrete,  reinforced  (see  also  concrete), 
abutments,  595,  635. 

adhesion  of  reinforcements,  187,  663, 
665. 

advantages  of,  635. 
aggregates  ,used,  674. 

specification,  857. 
American    system    of    reinforcing  for 
concrete  construction,  704. 

system,  703. 
anchors  for  brick  facing,  860. 
armored  concrete,  594. 
balcony   platforms,   specifications,  860. 
beams,    formulas,    assumptions  made, 
650. 

formulas,   T-Beams,   657,  659. 

formulas,  check,  657. 
beams  and  girders,  design  of,  649. 

breadth   of,  663. 

cantilever,  635.  ^ 

compression  rods,  665. 

determination   of  size,  655. 

manner  of  failure,  648. 

notes  on,  647. 
bending  moments,  661,  662. 
bins,  636. 
bridges,  635. 

buildings.  Bullock  Electric  Co's.  build- 
ings, Norwood,  Ohio,  695,  696. 

general  use  in,  635. 

Ketterlinus  building,  Philadelphia, 
Pa.,  715,  716,  717,  718. 

Lord  Baltimore  Press  building,  Bal- 
timore, Md.,  710.  712. 

Lynn  Storage  Warehouse,  Lynn, 
Mass.,  707,  708. 

McGraw  building,  New  York,  719. 

Salem  Laundry  buildings,  Salem, 
Mass.,  698. 

Textile  Machine  Works,  Reading, 
Pa.,  721. 

Warehouse  for  W.  H.  Edgar  &  Sons 
Company,  Detroit,  Mich.,  710, 
711. 

cantilever  foundation  construction,  86. 
caps,  742,  864. 
cement,  Portland,  849. 

Portland,   anhydrous  sulphuric  acid, 
850. 
fineness,  849. 
set,  849. 

specific   gravity,  849. 
soundness,  849. 

tensile     strength     in  reinforced 
work,  849. 
quality,  849. 
storage,  849. 


928 


INDEX, 


Concrete,  Reinforced. 


testing,  849. 
cements  used,  674. 
centering,   specifications,  851. 
chimneys,  636. 
Columbian  system,  704. 
columns,  695. 

cost,  667. 

design,  667. 

examples  of,  670. 

hooped  reinforcement,   672,  673. 

length,  667. 

reinforcement,    longitudinal,  amount 
and  disposition  of,  671. 
wrapped,  672,  673. 

space  occupied,  667. 

strength  of  longitudinally  reinforced, 
668. 

composite  concrete  and  structural  steel 

system,  715. 
concrete    and    steel    in  combination, 

properties  of,  679. 
contractor's  plant,  specifications,  857.  , 
copings,  concrete,  861. 
corrosion,  protection  against,  725. 
corrugated  bar  reinforcing  system,  705. 
Cummings  system,  704. 
concrete-and-tile  system^,  709,  710,  711, 

713. 

concrete  blocks,  742,  743. 
concretes,  consistency  of,  676. 

elastic  properties  of,  676. 

kinds  used,  674. 

strength  of,  676. 
conduits,  635. 

construction  in  general,  specifications, 
850. 

culverts,  use  in,  635. 
dams,  635. 
definition,   594,  632. 
depositing,  specifications,  857. 
,in    freezing    weather,  specifications, 
859. 

in  warm  weather,  specifications.  859. 
design,  bending  moments,  661,  662. 

modulus  of  elasticity,  660. 

T-beams,  657,  659. 

working  unit-stresses,  659. 
erection,  726. 
examples,  early,  636,  642. 
expanded-metal  and  round  bar  system, 
707. 

Faber  system  of  tile  and  concrete,  707. 

facing,  terra-cotta,  431,  432. 

false  work,  specification,  851. 

ferro-concrete,  594. 

fiber-stress  allowed,  extreme,  660. 

fire-proofing  structural  steel,  861. 

fire  protection,  722. 

floor,  floors   (see  also  floor,  floors). 

floor  slabs,  655,  656,  657,  658. 

surfaces,  cement,  860. 
floors,  Ransome,  636,  637,  641. 
footings,  48,  717. 
forms,   specifications,  851. 

removal  of    specifications,  852. 
Gabriel  system,  709. 
girders,  latticed,  720,  721,  722. 
gussets,  specifications,  859. 
Hennebique  system,  710. 
history,  632. 
inspection,  727. 

Johnson  bar  reinforcing  system,  705. 
Kahn  bar  with  plain  rods,  710. 
lintels,  718,  742,  864. 

specifications,  859. 
"M"  system,  713. 
materials  of,  674. 

properties  of,  643. 


proportions  of,  675. 
Merrick  system,  713. 
mill  construction,  702. 
mixing,  specifications,  857. 
mixtures,  retaining-walls,  105. 

wet  and  dry,  676. 
moduluses  of  elasticity,  660. 
monolithic  construction,  632. 
mushroom   system,  713. 
percentage  of  reinforcement,  663. 
piles,  636  (see  also  concrete  piles), 
pipe  sleeves,  specifications,  856. 
proportions  of  materials,  specifications, 
857. 

protection    of,    general  considerations, 
722. 

reinforcements     (see     also  Reinforce- 
ments), 
reinforcements,  677. 

amount    and    disposition    in  beams, 
662. 

bars  and  rods,  plain,  680. 

with  stirrup  and  truss  attachment, 
684. 

cold-twisted  lug  bar,  680. 

column  and  pier,  695. 

Cummings    loop    truss    unit  frame, 

688. 
cup  bar,  681. 

deformed  bars  and  rods,  680. 
De  Man  bar,  681. 
diamond  bar,  681. 
economy  imit  frame,  688. 
Golding  bar,  684. 
Hennebique  system,  685. 
Johnson  corrugated  bar,  682. 
Kahn  bar,  685. 

pin-connected  girder  frame,  690. 
placing,  specifications,  853. 
Ransome   bar,  6d2. 

Ransome  bar,  pulling  out  tests,  666. 

specifications,  852. 

steel,  677. 

stirrups,  687. 

Thacher  bar,  684. 

types  of,  679. 

unit  concrete  steel  frame,  692. 
systems,  687. 
retaining-walls,   104,  635. 
rubble,  594. 

sand,  specifications,  856. 
sewers,  635. 

shop  drawings,  specifications,  856. 
shores,  specifications,  851. 
shrinkage,  602. 
sills,  742,  861,  864. 
skeleton  construction,  703. 
slabs,  design,  662. 

determination   of  dimensions,  655. 

for  floors,  718. 

strength  of,  655. 
slag,  heat-resistance,  446. 
sockets  in  beams  and  girders,  specifi- 
cations, 855. 
specifications,  849. 
stairs,  580,  581,  582. 

construction,  specifications,  860. 
steel    and    concrete    in  combination, 

properties  of,  679. 
stopping  work,  specifications,  858. 
strength  of  wet  and  dry  mixtures,  676. 
stress,  allowable,  50. 

compressive,  maximum  allowable,  53. 

diagonal  tension,  664. 

in  structural  members,  643. 

safe  average  unit,  601. 

vertical  shear,  664. 

working  unit,  659. 


INDEX. 

Concrete- aucl-Bilok   Coiiistriietion — Couerete  Curbing. 


929 


structural  members,  stresses  in,  643. 
subdivisions  of  subject,  632. 
systems  of  construction,  701,  702, 
tanks,  636. 

test  cubes,  specifications,  857. 

theory  and  design,  general  considera- 
tions, 642. 

ties    for    brick    facing,  specifications, 
860. 
railroad,  636. 

tile,   hollow,   used  with  concrete,  707. 
710. 

towers,  636. 

trusses,  Visintini  system,  720,  721,  722. 
types  of  construction,  701,  702. 
unit-construction,  632. 
uses,  634. 

Visintini  system,  721. 

walls,  reservoir,  635. 
Concrete-and-brick  construction,  621. 
Concrete-and-brick  vaults,  383,  384. 
Concrete-and-stone  footings,  88. 
Concrete  aqueducts,  594. 
Concrete  arches,  595- 

Concrete  beam   and  girder  protection  (see 

beams  and  girders,  fire-pifoofing) . 
Concrete  block  construction, 

details  of,  745- 

general  considerations,  728. 
Concrete  blocks, 

absorption  test,  867. 

advantages,  729. 

age  of  blocks,  863. 

aggregates,  size  of  pieces,  730,  731, 

air-space,  one,  733. 

applications  for  use,  865. 

arches,  746. 

bond,  863. 

brand  marks,  868. 
of  identification,  864. 

building  regulations,  746. 

buttresses,  864. 

cap  construction,  864. 

cement,  Portland,  use  of,  865. 
tests,  864. 

certificates  of  tests,  864. 

color  of  face  surface,  744. 

columns,  698. 

compared  with  cement  bricks,  334. 
composition,  862. 
compression  tests,  867. 
compressive  strength,  868. 
concrete,  mixing,  731. 
condemned  blocks,  865. 
conditions  for  approval,  868, 
damp-resistance,  741. 

face  surfaces,  744. 
defective  blocks,  865. 
door  and  window  jambs,  746. 
facing,  744. 

facing  of  the  blocks,  character  of  mix- 
ture, 741. 
fire-proofing,  columns,  459. 
fire  tests,  867. 
flexural  strength,  868. 
forms,  different.  732. 
forms  for  making,  744. 
formula  for  modulus  of  rupture,  867. 
freezing  test,  867. 
heavy  blocks  for  sea-walls,  611. 
hollow  spaces,  percentage,  862. 

walls,  734. 
identification  marks,  868. 
inspection,  865. 
lintel  construction,  864. 
loads,  maximum,  863. 
machines  for  making,  744. 


manufacture,  743,  744. 

outline  of  early  history,  728. 
materials  for,  730. 
mixing  the  concrete,  731. 
modulus  of  rupture,  868. 

formula,  867. 

tests  for,  866. 
molds  for  making,  744. 
one-piece,  staggered  webs  and  spaces,  741. 
ornamentation,  744. 
partitions,  542,  746. 
piers,  864. 

proportions  of  materials  for,  730. 
regulations  governing  use  and  manufac- 
ture, 862. 

reinforced  for  concentrated  loads,  745. 

with  wires,  742,  743. 
samples,  864. 

testing,  865,  866. 
shape  of,  732. 
sill  construction,  864. 
solid,  734. 

for  concentrated  loads,  745,  863. 
special  and  miscellaneous  types,  741. 
specifications,  865. 
strength,  740. 

compressive,  868. 

crushing,  863. 

flexural,  868. 

test   for   transverse,  866, 
tests,  863,  864. 

absorption,  867. 

compression,  867. 

fire,  867.  ; 

freezing,  867. 

modulus  of  rupture,  866, 

of  cements  used,  864. 

required,  865. 

results  of  filed,  866. 

samples,  865,  866. 

transverse,  866. 
thickness  of  walls,  863. 
trim,  method  of  fastening,  746, 
two-piece,  735. 
uses  of,  729,  862. 
wall-plugs,  metal,  746. 
walls,  foundation,  745, 

hollow,  732. 

thickness,  863. 
water-proof  surfaces,  744, 
webs,    four,    with    three    air-spaces,  733, 

three,  with  two  air-spaces,  733. 
weight,  740,  866. 
Concrete  block  backing,  walls  of  stone,  con- 
crete or  terra-cotta,  737,  738. 
Concrete  block  foundation  walls,  footings, 

745- 

Concrete  block  walls, 

air-spaces,   percentage   of,  740. 

anchors  for  joists,  740,  741. 

angular  block  construction,  741. 

cement  brick-backed,  742,  743. 

brick-veneered,    737,  738. 

damp-proof  courses,   slate,  742, 

flues,   740.  : 

girder  and  beam  supports,  745, 

joist  supports,   740,   741,  745,  I 

loads,  concentrated,  745.  1 

thickness,   745.  ) 

width,   740.  J 
Concrete  breakwaters,  595. 
Concrete  bridges,  595. 
Concrete  capping,  wooden  piles,  37. 

with  imbedded  rods,  38. 
Concrete  cliimneys,  595. 

Concrete    construction     (see  construction, 

concrete). 
Concrete  curbing,  862. 


930 


INDEX. 


Concrete  Dams — Construction. 


anchoring  of  reinforcement,  ii8. 
cost,  1 1 8. 

protection  for  edge,  ii8. 

reinforcing,  ii8. 
Concrete  dams,  595. 
Concrete  dikes,  595. 
Concrete  domes,  638. 
Concrete  fence  posts,  595. 
Concrete  filling,   between  beams,  mixture, 

S8. 

between  pijes,  38. 

haunches  of  brick  floor  arches,  466. 

floor  arches,  tile,  470,  471.  477- 
Concrete  floor  arches  (see  floors,  fire-proof). 
Concrete  floors  (see  floors,  fire-proof). 
Concrete  footings,  87, 
advantages  of,  87. 

amount  of  steel  reinforcement,  formula, 
53. 

bearing  area,  52. 
building  laws,  requirements,  88. 
•cantilever  construction,  84. 
columns,  reinforced,  50. 
deformed  bars  for  reinforcing,  48. 
depositing  the  concrete,  52. 
design  of  reinforced,  48. 
economy  of,  87. 
failure  by  flexural  stress,  52. 
mass  concrete,  622. 
longitudinal  reinforcing  rods,  50. 
maximum  compressive  stress  on  rein- 
forced, formula,  54. 
mixture  of  concrete,  52. 
placing  the  rods,  57. 
planking  for,  88. 
reinforced,  48,  695,  696,  717. 

area  of  reinforcement,  54. 

column,  spread,  52. 

depositing  layers  of  concrete,  52. 

heavy  loads,  50. 

rods,  48,  52. 

rule  for  finding  maximum  compres- 
sive stress  on  concrete,  54. 
strength  of,  49,  52,  56. 
theoretical  depth,  52. 
thickness  and  width,  52. 
use  for  walls,  piers  or  columns,  49. 
vertically,  50. 
with  deformed  bars,  51. 
with  Kahn  trussed  bar,  51. 
with  stirrups,  51. 

with  steel  beams,  use  of  strength  of 
concrete,  49. 
Tock  foundations,  5. 
specifications,  818. 
spread  for  heavy  wall,  50. 
thickness  and  width,  88. 
trenches  for,  88. 
Concrete  fortifications,  595. 
Concrete   hollow   block   walls,  damp-resist- 
ance, 732. 
heat  resistance,  732. 

ventilation  of  wall  spaces  and  rooms,  732. 
Concrete  mixers,  concrete  blocks,  731. 
Concrete  partitions  (see  partitions). 
Concrete  penstocks,  595. 
Concrete  piles,  595. 

advantages,  39. 

.comparison  with  concrete  piers,  39; 

illustration,  40. 

with  wooden  piles,  39. 
compressol  system,  advantages,  45. 

capping  piers,  45. 

construction,  method  of,  45. 
rapidity  of,  47. 

economy,  47. 

elimination  of  dangers,  47. 
filling  and  tamping  concrete,  45. 
spread  at  bottom,  45. 


strength  of  pillar,  45. 

weight  for  perforating  and  comparting 
soil,  45. 
•   corrugated,  44. 

damage  by  hammer,  45. 

driving,  44. 
head,  44. 

molding,  44. 

reinforcing,  45, 
cost  of,  47. 
permanency,  41. 
Raymond,  42. 

filling  in  concrete,  42. 

forming  mold,  42, 

reinforcing,  42. 
reinforced,  636. 
simplex,  43. 

cost  of,  48. 

alligator-jaw,  44. 

filling  in  concrete,  44. 

mixtures,  48. 

non-uniformity   of  cross-section,  44. 
perietration   shoe,  43. 
sustaining  power,  39. 
types,  41. 
Concrete    reservoirs,  595. 
Concrete    retaining-walls    (see  retaining- 

walls,  104). 
Concrete  roads,  594, 
Concrete  sewers,   594,  595. 
Concrete   sills    (see  Sills). 
Concrete    skewbacks,    advantages,  94. 
Concrete    standpipes,  595. 
Concrete-steel  (see  concrete,  reinforced). 
Concrete-Steel  Engineering  Co.,  New  York. 
Concrete,    reinforced,    Visintini  system, 
721. 

diamond  bar,  681. 

Thatcher  bulb  bar,  684. 
concrete  floor  unit,  530. 
Concrete  stone,  artificial,  261,  262. 
Concrete  subways,  595. 
Concrete  tanks,  595. 
Concrete   ties,    railroad,  595. 
Concrete  tunnels,  595. 
Concrete  vats,  595. 

Concrete  walls,  curtain-wall  panels,  703, 

facing,  brick,  703. 
Concrete   water   conduits,  595. 

mains,  594, 
Concrete  wharves,  595. 
Concreting  tile  floor  arches,  specifications, 
834.. 

Conductive,    concretes,  723. 

fire-proofing   materials,  448. 

heat  in  fire-bricks,  324. 

partitions,  541. 
Conduits,  concrete,  reinforced,  635. 
Conglomerates,  263. 

Congressional  Library,  Washington,  D.  C, 

quality  of  soil  under,  12. 
Consistency    of    concrete     (see  concrete, 

consistency). 
Constant  for  strength  for  various  woods,  70. 
Construction, 
brick,  compared  with  wood  construction, 

311. 
concrete,  311, 
brick-faced,  718. 
classes  of,  608. 
faihtres  in,  causes,  611. 
puddlers,  630,  631. 
rammers,  630,  631. 
fire-proof,  cost  compared  with  non-fire> 
proof,  436. 
definition,  Chicago,  437. 
New  York  City,  437. 
Philadelphjg^  438. 


INDEX. 


931 


Continuous  Foundations — Cross  Walls. 


lathing  and  plastering,  804. 
ret^ining-walls,  103. 
skeleton,    bak-window    supports,  766. 

cornice  supports,  764. 

ironwork,  miscellaneous,  768. 

reinforced  concrete  work,  703. 

spandrel  supports,  756. 

steel  lintel  supports  for  masonry,  760. 

wall  columns,  768.  ' 

wall   supports,   753.  ■ 
terra  cotta,  311.  • 
wood,  compared  with  brick  construction,  i 
311. 

beams,  644,  645. 
•Continuous  foundations  on  different  soils, 
14. 

kilns,  320. 
Contract,  excavating  included  in,  24. 
foundation,  24. 

payment     included     for     extra  trench 
masonry,  24. 
Contraction,  concrete  in  setting,  602. 

masonry,  301. 
Contractor's    plant,    concrete,  reinforced, 

specifications,  857. 
Contractor,      responsibility      staking  out 
buildings,  2. 
rules   for,   in   staking   out   buildings,  2 
Convents,  walls,  thickness  of,  908. 
Coping,  Copings, 
anchors,  293. 
area  walls,  112. 
brick,  340. 

concrete  specifications,  861. 
cornices  of  brick,  344. 
drips,  292, 
gable,  292,  309. 
stone,  273,  292,  309. 
stones,   length  of,  293. 

suitable,  112. 
terra-cotta,  architectural,  418,  419. 
use  of  cement  mortars,  188. 
weathering,  292. 
■Copper, 

crown-molds  for  brick  cornices,  344. 
roofing,  536. 
Corbels,  brick  walls,  for  joists,  358. 
Corner-beads,  "Universal"  steel,  565,  566. 
Cornice  profiles,  furring  of  metal  for,  575, 

576,  577. 
■Cornices, 

brick,  325,  341,  342,  343,  344,  345. 
anchoring,  342, 
Bologna,  Italy,  345. 
churches,  344. 
crown-molds  of  metal,  344. 
heights,  345. 
pitched   roofs,  344, 
interior,   tile  grounds,   577,  578. 
stone,  275,  276,  292. 
measurement  of,  305. 
width  of,  265. 
wood,  in  brick  bed-molds,  343. 
Corridor  partitions,  541,  549. 
Corrosion, 

metal  lath  in  plaster,  550. 
reinforcements  in  concrete,  725. 
slate,  884,  897. 
steel  in  cinder  concrete,  446. 
Corrugated    bar    reinforcing    system  (see 
concrete,  reinforced), 
concrete  piles,  44. 
■^Cost, 

ashlar,  broken,  265. 
coursed.  265. 
picked  finish,  274. 
rock-faced,  271, 
backing,  stone  and  brick,  299. 


brick  manufacture,  316. 
bricks,  enamelled,  321. 

glazed,  321, 

pressed,  325. 

rubbed  standstone,  273. 
buildings  in  the  United  States  in  1905 
and  1906,  900. 

in  1906,  901. 
cantilever  foundation  construction,  86. 
concrete,  604. 

mass,  610. 

mixing,  625. 

walls,  624,  625. 
cut-stonework,  275,  311. 
fire-proof    compared    with  non-fire-proof 

construction,  436. 
forms  for  mass  concrete,  630. 
Guastavino  tile  arch  construction,  496. 
joints,  joggled,  288. 
marble,  232. 

partitions,  metal-and-plaster,  556. 
piles,  concrete,  47. 

wooden,  39. 
rock-faced  work,  273. 
rubble-work,  311. 
slate,  roofing,  245,  897. 
stone  arches,  283. 

for  building,  205,  255. 

sills,  280. 

steps  and  stairs,  293,  294. 
stone-work,  306,  307. 
terra-cotta,  architectural,  422. 
Cord  of  stonework,  307. 
Cornices, 
false,  833. 

wire  lath-covered,  841. 
furring,  tile,  833. 
plaster,    specifications,  838. 
stone,  275. 

steel  supports  for,  764. 
terra-cotta,  423,  424,  425,  426,  427,  764, 
765,  766,  835. 
supports  for,  764,  765,  766. 
washes,  276. 
Coursed-ashlar  work,  264. 
arches  in,  283, 
random,  266. 
Coursed  stonework, 

irregular-coursed-ashlar,  265. 
regular-coursed-ashlar,   265.  ' 
Courses, 

ashlar  work,  heights  of,  296. 

thickness  of,  296. 
stonework,  dimensions,  265. 
Court-houses,  walls,  thickness  of,  910. 
Courts,  brick  facing,  glazed  and  enamelled, 

322. 
Cracks, 

adjoining  high  and  low  walls,  303. 
arches,  281. 

stone,  310. 
brick  piers,  295. 

walls,  365. 
bricks,  312. 

paving,  323. 
caused  by  unequal  settling,  rock  founda- 
tions, 6. 
columns,  stone,  310, 
cut-stonework,  298,  301. 
fire-bricks,  324. 
in  buildings,  21. 

mason  work  of  buildings,  causes,  15. 
stone  arches,  285. 

sills,  298,  301. 
voussoirs,  284. 
Crandall  for  stone  dressing,  270. 
Crandalled  work,  273, 
Cross  walls,  .101. 


932 


INDEX. 


Crown — Draft-lines. 


Crown,  of  stone  arches,  281. 
Crown-molds,    metal,    for    brick  cornices, 
344- 

Crown  sanitary  flooring,  534- 
Crushing  strength  (see  strength  crushing). 
Culverts,  concrete,  reinforced,  635. 
Cummings,  Robert  A., 

concrete,    reinforced,    type    of  construc- 
tion, 704. 

hooped  concrete  column,  696. 

loop  truss  unit  frame  (see  concrete,  re- 
inforced). 

system  (see  concrete,  reinforced). 
Cummings,  Uriah,  natural  cements,  143. 
Cunningham,   Edward,  mortars  impervious 

to  water,  196. 
Cup  bar  (see  concrete,  reinforced). 
Curbstone,  Curbstones, 

concrete,  118,  862. 

lines  cut  on,  staking  out  buildings,  3. 
measurement  of,  307. 
production,  1905  and  1906,  208,  209. 
sidewalls,  118. 
support,  116. 
thickness,  117. 
Curtain-walls, 
brick,  363. 

concrete  construction,  703. 
Cut-stone  vaults,  280. 
Cut-stone  arches,  280. 
Cut-stonework, 

anchors,  823. 

backing,  299. 

bonding,  300. 

cleaning,  302. 

cost,  275,  3T1. 

cracks,  301. 

dampness,  300. 

defects  in,  308. 

face  joints,  310. 

general  treatment  in  walls,  295. 

granite,  specifications,  821. 

joints,  296,  298. 

Lafarge  cement,  301. 

measurement  of,  306. 

patching,  308. 

pointing,  301,  310. 

protection  of,  301. 

setting,  300,  823. 
specifications,  829. 

settlements,  298. 

specifications,  821. 

strength,  303,  304,  305,  306. 

superintendence,  308. 

workmanship,  309, 
Cutting, 

stone,  broken   ashlar,  265. 
trimmings,  267. 

and  finishing  of  stone,  269. 

and  fitting  brickwork,  829. 

terra-cotta,  architectural,  836. 
Cutting-tools  for  stone,  269. 

D 

Dampness, 
bricks,  311. 

cut-stonework,  mortar,  300. 

in   foundation    walls,   general  considera- 
tions, 109. 

Damp-proof  courses,  slate  in  concrete  block 

walls,  742. 
Damp-proofing, 
brickwork,  399. 
cellar  floors,  iio. 

walls,  109. 
constructive  devices  for  foundation  walls, 
I II. 

flagging  apound  building,  iii. 


footings,  109. 

of  walls,  piers,  etc.,  110,  * 
Damp-resistance, 

366,  367,  399,  400,  401. 

concrete  block  walls,  732,  733. 
blocks,  741. 

face  surfaces,  744. 

terra-cotta,  architectural,  411,  412. 

stonework,  260. 

wall-facing,  released,  592. 
Dams, 

concrete,  595. 
reinforced,  635. 
Dash  work,  exterior  plastering,  798. 
Deep  rock  fissures,   spanned  by  arches  of 

brick  or  stone,  6. 
Defective  foundations,  5. 
Defects,   stones   and  stonework,  308. 
Deformed  reinforcing  bars  and  rods  (see 

reinforcements). 
Denmark,     introduction     of  silica-cement 

process,  170. 
Denver,  Col.,  brick  foundations,  91. 
De  Man  bar  (see  concrete,  reinforced). 
Delays  caused  by  too  small  excavations,  24, 
Dense  tiling  (see  tiling,  dense). 
Density, 

bricks,  317. 
paving,  323. 

cement  bricks,  334. 
Depositing  concrete,  598, 

mass  construction,  610. 
Depth,   foundations,   designing,  13. 
Derricks,  setting  large  stones,  300. 
Design  of  retaining-walls,  103. 
Details,  brickwork,  379. 
Detroit  Fire-proofing  Co., 

gypsite  column  covering,  459. 
Detroit   Fire-proofing   Tile   Co.,  Pittsburg, 

Pa.,  gypsite  partitions,  545. 
Devices,  fire-proofing,  miscellaneous,  582. 
Diagonals,  use  of  in  staking  out  buildings,' 3. 
Diamond  bar  (see  concrete,  reinforced). 
Diamond  mesh  expanded-metal  lath,  564. 
Diamond     Stone-Brick     Co.,  Wilmington, 

Del.,  sand-lime  products,  261. 
Diaper  work,  brickwork,  346,  347. 
Dies,  brick  manufacture,  315. 
Different  levels,  rock  foundations,  6. 
Dike  slakes,  898. 
Dikes,  concrete,  595,  611. 
Dimension-stone, 

cost  of,  306.  ' 

measurement,  units,  306,  307. 

piers,  303. 

sizes,  90. 
Dimension-stones, 

width  and  length  of,  90. 
District    surveyor,    street   and   party  lines, 

staking  out  city  buildings,  3. 
Dolomite,  227. 

Dome  construction,   Guastavino,  495. 
Domes, 

concrete,  638. 

Guastavino    construction,    recent  typical 

large  domes,  497. 
terra-cotta,  429,  430,  431. 
Door-guards,  jamb  protection,  769. 
Door  sills  (see  sills,  door). 
Doorsteps,  stone,  280. 
Dormitories,  walls,  thickness  of,  908. 
Dowelling  iron  balusters  into  stone  steps, 
294. 

Dowels,  anchoring  stone  finials,  310. 
Down-draft  kilns,  319. 
Draft,  brick  kilns,  318. 
Draft-lines, 

arch   voussoirs,  282. 

stonework,  270,  271,  272. 


INDEX. 


933 


Drain— Excavation. 


Drain,  footings  laid  dry,  blue  clay  foun- 
dations, 7. 

in  trenches  around  foundation  walls,  iii. 
stone  for  footing  drains,  24. 

foundations  in  clay,  8. 
subsoil,  clay  soils,  7. 

tile,  use  of,  foundations  on  clay  soils,  8. 
for  footings,  24. 
Draining, 

surface  water,  rock  foundations,  5. 

water  from  excavations,  24. 
Drawings, 

ashlar   stonework,   295,  296. 

quoins  and  jambs  in  ashlar,  296. 

shop,  concrete,  reinforced,  specifications, 
856. 

Dressed  stonework,  hammer-dressed,  264. 
Dressing  stones,  different  kinds,  271. 
Drift-bolts, 

securing  timber  footings,  71. 

timber    gullage    capping    to  wooden 
piles,  38. 
Drips,  275,  276. 

brickwork,  340. 

copings,  292. 

cornices,  brick,  344. 

joints  in  brickwork,  337. 
Driveways, 

brick-paved,  322. 

over  segmental  tile  floor  arches,  473. 
Drop-hammer, 

driving  wooden  piles,  28. 

fall  of,  29. 

weight  of,  28. 
Drove, 

for  stone  dressing,  271. 
Drove-work,  272. 
Dry-clay  bricks,  315. 

Dry  drains,  areas  in  sandy  soils,  112. 
Dry-houses,  brick  manufacture,  313. 
Dry  masonry,  footings,  24. 
Drying  bricks,  318. 

Drying-sheds,   brick  manufacture,  314. 
Dry-pans,  brick  manufacture,  316. 
Dry-pressed  bricks,  316. 
Dry  soils,  brickwork  in,  311. 
Ducts, 

cold-air,  specifications,  828. 
furring  for,  573,  575. 
Duplex  wall-hangers,  356,  357. 
Durability, 

bricks,  311,  317. 

glazed  and  enamelled,  321. 
paving,  323. 
lime  mortar,  135. 
stone,   building,   251,  311. 
terra-cotta,  architectural,  411. 
woods,  under  water,  27. 
Durand-Claye,  M.,  cements,  strength  tests, 
187. 

Dwarf  walls,  to  prevent  cracks,  21. 
Dwellings, 

computing  weight  on  footings,  16. 

fire-proof,  582,  583,  584,  585,  586. 

masonry  walls,  300. 

stone,  drawings  for  cut-stonework,  296. 
walls,  thickness  of,  908. 


Earthquake-resisting  construction  in  fire- 
proof  buildings,  587. 

Eastern  Expanded  Metal  Co.,  Boston, 
Mass.,  concrete,  reinforced,  type  of 
construction,  707. 

Eastern  Hydraulic  Press  Brick  Co.,  Phila- 
delphia, 345. 

Eaves,  overhanging  brick  cornices,  345. 

Eckel,  Edwin  C, 


bricks,  sand-lime,  330. 

composition  for  hydraulic  limestone,  :36. 
definition  of  Portland  cements,  162. 
fineness  of  natural  cements,  152, 
hardening  of  lime  mortars,  134. 
natural   cements,   varieties   and  qualities 

of  different  brands,  142. 
Portland  cements,  specifications  for,  178. 
raw    materials    available    for  Portland 

cements,  165. 
shale  at  Defiance,  Ohio,  natural  cements, 

143- 

specifications  for  Puzzolan  cements,  181. 
varying  specifications  for  natural  cements, 
153- 

Economy  Manufacturing  Co.,  New  Haven, 

Conn.,  stone,  artificial,  261. 
Economy  unit  frame   (see   concrete,  rein- 
forced). 

Eddystone     lighthouse,     use     of  natural 

cement,  141. 
Efflorescence, 

brickwork,  336,  341,  398. 

bricks,  sand-lime,  332. 

plastered  tile  ceilings,  469. 
Egyptian,  early  use  of  cements,  141. 
Eight-cut  stone  finish,  274. 
Elastic  elongation,  steel,  679. 
Elastic  limit,  concrete,  601. 

steel,  677. 

reinforcing  wire,  600. 
Elastic  properties,   concretes  in  reinforced 

work,  676. 
Elasticity, 

coefficient  of    (see  modulus  of  elasticity). 

modulus  of    (see  modulus). 
Electric  Welding  Co.,  Pittsburg,  Pa.,  Cum- 

mings  loop  truss  frame,  688. 
Elevator  shafts  (see  shafts,  elevator). 
Ellendt  reinforced  block  partition,  545. 
Elliptical  arches,  282,  285, 

abutments,  286. 

failure  of,  286. 

joints,  286. 
Elongation,  elastic  steel,  679. 
Enamelled  bricks  (see  bricks,  enamelled). 
End-construction, 

floor  tile,  flat  arch,  480. 
segmental  arches,  473. 

concrete  tile,  528. 
End-cut  bricks,  315. 
Engine  foundations,  concrete,  595. 
Engineer  Corps,  U.  S.  Army,  specifications 

for  natural  cements,  845. 
Engineering  News  formula  for  safe  work- 
ing loads  on  piles,  32. 
England, 

brickwork,  ornamental,  340. 

hydraulic  limestone,  138. 

Leeds,  invention  of  Portland  cement,  163. 

manufacture  of  Portland  cements,  163. 

Roman  cement,   141,  144. 

selenetic  lime  and  cement,  197. 
Entablatures,  stone,  292. 
Entrance,  areas,  113. 

Entrance  platform  at  bottom  of  steps,  114. 
Erie  Canal,  natural  cements,  141, 
Erection   of   reinforced  concrete  construc- 
tion, 726. 
Eureka  tile  floor  arch,  488. 
Europe, 

bricks,   sand-lime,  329. 

compression  tests  on  cements,  186. 

grouting,  193. 

materials   for   Portland   cements,  166. 
European  buildings,  stone  stairs,  293. 
Excavation, 

adjacent  to  foundations  on  clay  soils,  7. 


934 


INDEX. 

Excelsior  Tile  Floor  Arch — Fire-proof  Paint, 


areas,  deep,  113. 
area  walls,  105. 
beyond  wall  lines,  24. 
contract  for,  24. 

delay  caused,  when  too  small,  24. 
draining  water  from,  24.  ^ 
inspection  of,  23. 
piers,  24. 

sand  foundations,  9. 
specifications,  816. 
testing  soils  in,  24. 
trenches,  24. 

water  in,  24.  o       o  q. 

Excelsior  tile  floor  arch,  477.  481.  4o3.  4»4- 
Expanded-metal,  562,  564,  565,  566. 

furring  for  architectural  forms,  570. 

and  round  bar.  system  (see  concrete,  re- 
inforced). 

lath  (see  lath,  metal). 

reinforcement  (see  reinforcements). 
Expanded  Metal  and  Corrugated  Bar  Co., 
St.   Louis,   Mo.,   concrete,  reinforced, 
types  of  construction,  705. 

economy  unit  frame,  688. 

Johnson  corrugated  bar,  682,  683. 
Expansion, 

coefficient  of  slates,  897. 
of  steel,  679. 

concrete  in  setting,  602.  ,i' 

masonry,  301. 
Experiments, 

(see  also  tests). 

bearing  power  of  wooden  piles,  34. 

effect  of  sugar  on  Portland  cement,  i97- 
Extra    payments,    masonry    for    too  deep 

trenches,  24. 
Extrados,  arches,  281. 

F 

Faber  Construction  Co.,  New  York  N.  Y., 
concrete,  reinforced,  type  of  construc- 
tion, 709. 

system  of  tile  and  concrete,    (see  con- 
crete, reinforced). 
Fabrics,   triangular   steel   mesh,  reinforce- 
ments for  concrete  partitions,  558. 
Face-bricks,  325,  338. 
colors,  326. 
dry-pressed,  317. 
Face-wall,  see  retaining-wall,  loi. 
Facing, 

brick,  concrete  walls,  703. 

glazed  and  enamelled,  for  walls,  322. 
on  concrete,  718,  860. 
concrete  blocks,  863. 
stone  walls,  264. 
terra-cotta,  architectural,  835. 
for  light-courts,  434. 
for  reinforced  concrete,  43 1»  432. 
wall,  Pelton's  released  facing,  590. 
Factor  of  safety, 
brick  arches,  402. 

piers,  402, 
concrete  beams,  reinforced,  649. 
stone  lintels,  305. 
piers,  303, 
Factories, 

floor  arches,  segmental,  472. 
walls,  thickness  of,  910. 
Fading  slates,  898,  899. 
Failure 

of  elliptical  arches,  286. 
mortar,  from  lack  of  cohesion,  194. 
retaininp'  walls,  102. 
"Fair"   building,   Chicago,   III.,   floors  and 

columns,  fire-proof,   471,  472. 
Falk,  Myron  S.,  cements,  mortars  and  con- 
crete, 186. 


False  beams,  tile,  833. 

False   columns   (see  columns). 

False  construction,   573,   576,  577. 

False  cornices,  tile,  833. 

False  joints,  stone  voussoirs,  283, 

False  mortar  joints,  263. 

False  pilasters   (see  pilasters). 

False  work,  concrete,  reinforced,  specifica 

tions,  851. 
Fawcett  ventilated  fire-proof  floor,  487. 
Feldspar  brick  manufacturing,  glazed,  320, 
Felt  roofing,  539. 

Fence-boards,  use  of,  in  staking  out  build 
ings,  2. 

Ferroconcrete   (see  concrete,  reinforced). 
Ferro-Concrete  Construction  Co.,  Norwood 
Ohio,  concrete  column  reinforcement 

Ferroinclave, 

partitions,  metal-and-plaster,  559,  560. 
stairs,   580,  582. 

concrete    floor   construction    (see  floors, 
fire-proof). 
Fibered 

cement,  789. 

plaster  partition  blocks,  545. 
Fibrous  plaster  (see  plaster). 
Fieberger,  Prof.  G.  J., 

expense     of     Portland     compared  with 
natural  cements,  148. 

Portland  cements,  171. 
Field 

rubble  walls,  specifications,  S21. 
stone  in  rubble  walls,  264. 

used   as    drain,    clay    foundations,  8, 

Fig.  6. 
Filled-in  ground, 

footings  on,  foundations,  9. 
foundations,  4,  9. 

general  practices  of  foundations  on,  25. 
Filled-in  rock  fissure,  "New  York  Times" 

bldg.  6.     Fig.  5. 
Filling, 

concrete,  cinder,  on  reinforced  concrete 
floors,  861. 

blocks,  tile  floors,  fire-proof,  472,  483. 

in  and  around  area  walls,  105. 
heavy  clay  soils,  108. 
trenches  behind  foundation  walls,  108. 

voids  in  stone  walls,  99. 
Fineness,   cement,   Poltland,   in  reinforced 

work,  849. 
Fine-pointed  stone  dressing,  272. 
Finials,  stone  anchoring,  310. 
Finish  for  stones,  dressing,  271. 
Finishing  and  cutting  of  stone,  269. 
Fire-bricks,  323, 

effect  on,  311. 

heat-resistance,  332. 

production,  value  of,  903,  905. 
Fire-clay, 

brick  manufacture,  enamelled,  321, 
Fire-clay  bricks  (see  bricks). 

paving  brick  manufacture,  322. 
Fireplaces, 

brick,  387. 

fire-brick  lining,  324. 
Fire-proof  buildings, 

cost,  average,  in   1906.  902. 
use  of  lime  mortar  in,  136. 
Fire-proof  floor  construction   for  covering 

sidewalk  vaults,  114. 
Fire-proof  dwellings  (see  dwellings). 
Fire-proof  flooring  (see  flooring,  fire-proof). 
Fire-proof  furring   (see  furring). 
Fire-nroof  Partition  Company,  New  York, 

Scaelioline,  543. 
Fire-proof   partitions    (see  partitions). 
Fire-proof  paint  (see  paint). 


INDEX. 


935 


Fire-proof  Roofs— Floor,  Floors. 


Fire-proof  roofs  (see  roofs,  fire-proof). 
Fire-proof  sash,  541. 
Fire-proof  stairs  (see  stairs). 
Fire-proof  window  frames,  541. 
Fire-proof  wood  (see  wood). 
Fire-proofing, 

beams  (see  beams,  fire-proofing), 

brick,  441. 

buildings,  divisions  of  subject,  439. 

general  considerations,  435. 
cast-iron  in,  446. 
clay  tile,  441. 

columns  (see  columns,  fire-proofing), 
concrete  in,  445. 

conductivity  of  protective  coverings,  448. 

definitions,  436. 

devices,  miscellaneous.  582. 

dwellings,  583,  584,  585,  586. 

floors,  460, 

brick  arches,  early  forms,  465,  466. 

concrete  construction,   advantages  and 
disadvantages,  498. 

Eureka  tile  three-block  flat  arch,  488. 

excelsior  tile  arch,  477. 

"Fair"  building,  Chicago,  111.,  471,  472. 
472. 

Fawcett  ventilated  fire-proof  floor,  487. 
framing,  steel,  long  spans,  464,  465. 
Government   printing   oflice,  Washing- 
ton, D.  C,  465. 
Johnson  tile  arch,  477. 
Lee  end-method  tile  arch,  480,  481. 
tile,  classification,  477. 

flat,    end-construction,    early  forms 
and  later  developments,  480. 
reinforced,  different  types,  489. 
Herculean,  493,  494,  495. 
Johnson  arch,  490,  492,  493. 
New  York  floor  arch,  489,  490, 
491. 

side-construction,  depth,  479. 

early   form   and   later  improve- 
ments, 477. 
joints,  479. 
webs,  479. 
arch,  end-construction,  advantages, 
482. 

end-construction,  joints,  484. 
materials  used,  482. 
objections,  482. 
skew-backs,  485. 
webs  and  voids,  484. 
arches,  end-construction,  keys,  484. 
general  description,  477. 
lintel  construction,  487. 
segmental,  different  types,  473,  474, 
475- 

end-construction,  473. 
photographs     of     typical  blocks, 
473,  475. 

typical  shapes  of  blocks,  478,  480. 
arches,  advantages,  467. 
disadvantages,  468. 
segmental,  rise,  475. 

skew-backs  and  keys,  types  of, 

474- 
thrust,  475. 
tie-rods,  475. 
specifications,  832. 
girders  (see  girders,  fire-proofing), 
in   connection    with  earthquake-resisting 

construction,  587. 
interior  finish  (see  interior  finish), 
materials,  440,  447,  448. 
mortar  in,  444. 

partitions,  tile  specifications,  833. 
pipes  near  columns,  460. 
plaster  of  Paris  in,  445. 


plasters  in,  144. 
roofs,  specifications,  832. 
specifications,  831. 
steel  in,  447. 
stone,  440. 

structural    steel    in    reinforced  concrete 
work,  861. 

terra  cotta,  441,  443. 

tests  on  floors,  461. 

trusses,  535,  536. 

wrought-iron  in,  447. 
Fire  protection,  concrete,  reinforced,  722. 
Fire-resistance  (see  heat-resistance). 
Fire  test,  concrete  blocks,  867. 
Fire-walls,  specifications,  829. 
Firm  soils,  foundations  on,  i. 
Fish  scale  stone  dressing,  275. 
Fissility,  grades  of  slate,  895,  896. 
Fissures,  in  rock,  filled-in,  foundations,  6. 
Flags,    stone    (see    also    slabs,    stone  and 

flagstones). 
Flagstone, 

around  buildings,  to  assist  in  damp-prouf 

ing,  III. 
measurement  of,  306. 
production,  1905  and  1906,  208,  209. 
strength  of,  306. 
Flashing, 

brick  belt-courses,  342. 

cement  flashing  on  belt-courses,  342. 

cornices  of  brick,  344. 

lead,  342. 

walls,  parapet,  344. 
Flat 

concrete   floor   construction    (see  floors, 
fire-proof). 

stone  arches,  288,  289. 
Flexure  beams,  644. 
Flexural  stress  (see  stress,  flexural). 
Flint, 

brick  manufacture,  glazed,  320. 
clay,  fire-brick,  324. 
Floor,  Floors, 

bridge  concrete,  595. 

concrete,    flat    arch,    Roebling,  strength, 

512. 
weights,  512. 
fire-proof  brick,  general  description,  465. 
classification,  463. 
concrete,  498. 

Berger  system,  512. 

Columbian  system,  506. 

Ferroinclave  system,  515. 

flat,  505. 

Merrick  system,  526. 
Roebling  flat  system,  509. 

segmental  system,  501,  502,  503. 
specifications,  843. 
sectional,  527. 
I-arch,  527. 
White  system,  518. 
Thatcher,  529. 
segmental,  500. 
unpatented  systems,  520. 
and  brick,  Rapp  system,  502. 
expanded  metal,  520. 
lock-woven  fabric,  522. 
steel  wire,  522. 
welded  metal  fabric,  523. 
finish  of  floors  and  ceilings,  470. 
framing  for,  464. 
general  considerations,  460. 
metropolitan  system,  445. 
tests,  standard,  461. 
tile,  467. 

combination     side-and-end  construc- 
tion, 487. 


936  INDEX. 

Floor  Arches — Forms. 


end  construction,  480. 

floor-block  or  lintel  construction,  487. 

Guastavino,  495. 

hollow  and  reinforced  concrete,  584. 
manner  of  setting,  467. 
protection  from  stains,  469. 
reinforced,  488. 
segmental  arch,  472. 
side-construction,  477. 
specifications,  832. 
top  surfaces,  proportions  of  cement  and 
sand  in  mortar,  190. 
Floor  arches, 

Roebling  concrete,  specifications,  843. 
brick,  kinds  used,  467. 
haunches,  466. 
loads,  safe,  467. 
Rapp  system,  467. 
rise,  466. 
skew-backs,  467. 
strength,  467. 
thickness,  466. 
thrust,  466. 
tie-rods,  466. 
weight,  466. 
concrete  (see  floors,  fire-proof), 
tile,  advantages,  467. 
disadvantages,  468. 
cambering,  468. 
centering,  468. 
segmental,  loads  on,  476. 
setting,  476. 
strength,  476. 
under  driveways,  473. 
weight,  476. 
weather,  effect  of  on,  469. 
Floor  coverings,  533. 

Floor  slabs,  concrete,  reinforced,  655,  656, 
657,  658. 

concrete,    reinforced,    bending  moments, 
662. 

Floor  strips,  wooden,  floors,  fire-proof,  470, 

Flooring, 

alignum,  534. 
asbestos,  534. 

granite,  534. 
asbestolith,  534. 
asphaltic,  533. 
cement,  533,  860. 
composition,  533. 
carborundum,  534. 
cement,  472. 
crown  sanitary,  534. 
elastic,  534. 
fire-proof,  533. 
heat-resisting,  534. 
Karbolith,  534. 
lignolith,  534. 

magnesia  building  lumber,  534. 

magnesite,  534. 

magnesium  chloride,  534. 

Monolith,  534. 

non-absorbent,  534. 

Puritan,  534, 

Rex,  534. 

sanitas,  534. 

sawdust,  534. 

wood,  533. 

concrete  floor  construction,  718. 

tile,  472,  533. 
Flue,  Flues, 

brick  smoke  flues,  383,  384,  385,  386,  387, 
388,   389,  390,  391. 

concrete  block  walls,  740. 
Flue  linings,  specifications,  828. 
Flue  thimbles,  828. 

Flux,  lime  in  brick  manufacture,  312. 
Fond  du  Lac,  Wis.,  sandstone  columns,  305. 


Footing,  Footings, 

area  walls,  level  of,  113. 
bottom  courses,  dry,  24. 
bricks, 

quality  of  bricks,  92. 
clay  soil,  7. 

concrete,  see  concrete  footings,  87. 

block  foundation  walls,  745. 
damp-proofing  course,  109,  110. 
different  levels,  foundations,  22. 
failure  by  bending  stresses,  49. 
draining,  24. 

grillage  (see  steel  beam,  footings,  58). 
foundations  partly  on  soil,  partly  on  rock, 
6. 

heavy  buildings,  90. 

bedding  of,  107. 

Colorado,  8. 

compressible  soils,  92. 

foundations  on  gravel,  9. 
height  of,   reduced  to  minimum,  94. 
inverted  arches,  94. 

materials,  94. 
laid  dry,  foundations  in  blue  clay,  7. 
level,  desirability  of,  rock  foundations,  6. 
light  buildings,  89. 
made  land,  foundations,  9. 
mud,  foundations,  9. 
partly  on  rock,  partly  on  soil,  6. 
piles,  filled  in  land,  9. 
pressure  on,  clay  soils,  7. 
proportioning,  to  the  weight  supported,  14. 
purpose  of,  87. 
ramming  trenches  for,  24. 
reinforced  concrete,  48. 
sand,  foundations,  9. 
settlement  of  building,  93. 
silt,  foundations,  9. 
stability  of  work,  93. 
steel  beam  (see  steel  beam  footings), 
stepped,  88. 

stone  (see  stone  footings), 
superintendence,  106. 
thickness,  increasing,  89. 
trenches,  heavy  buildings,  24. 
width  of,  87. 

widths,  calculations,  example  I,  and  so- 
lution, 17. 
calculations,    example    II,    and  solu- 
tion, 19. 
in  general,  18. 
Footing  courses,  care  of  inspection,  108. 
design  of,  89. 

importance  of  careful  construction,  93. 

projection  of,  89. 

proportionate  pressure,  91. 

safe  offsets,  table,  90. 

stone  example  of  offsets,  91. 
failure  by  cracking,  89. 
Footing  stones,  90. 

bedding  of,  90. 

irregular,  bedding  of,  107. 

jointed  under  center  of  wall,  89. 

over  pile  caps,  37. 
Forms, 

concrete  block  manufacture,  744. 
wood,  concrete  columns,  620,  621,  622. 
concrete,  mass  construction,  611. 

mass  construction.  Bullock  Electric 
Go's.  Shops,  Norwood,  Ohio,  621, 
622. 

cellar  walls  for  light  buildings,  625, 
626,  627,  628,  629,  630. 

concrete  columns  in  brick  walls, 
620,  621. 

cost,  630. 

device  for  preventing  forms  from 
bulging,  615. 


INDEX. 


937 


Formula— Furring:. 


examples  of,  613. 

foundation  footings,  618,  619. 

heavy  construction,  618. 

hollow  walls,  619,  620. 

materials  used,  611. 

miscellaneous  details,  612. 

movable  forms,  616,  617. 

Pacific  Coast  Borax  Refinery,  Bay- 

onne,  N.  J.,  614,  615. 
thickness  of  sheeting  and  size  and 
spacing  of  uprights,  629. 

of  wood,  611. 
when  removed,  630. 
reinforced,  removal  of,  specifications, 

852. 

specifications,  851. 
Formula,  breaking  flexural  strength  of  stone 

lintels,  305. 
Formulas, 

columns,  concrete,  longitudinal  reinforce- 
ment, strength,  668,  669,  670,^  671. 
concrete,  wrapped  or  hooped  reinforce- 
ment, 672,  673. 
concrete  beams,  reinforced,  650,  651,  657, 
659- 

T-beams,  reinforced,  657. 
Engineering    News,    for    safe  working 

loads  on  piles,  32. 
maximum  bending  moment,  grillage  beam, 
62. 

compressive  stress,  reinforced  concrete 
footings,  54. 
modulus  of  rupture,  concrete  blocks,  867. 
safe  working  load  on  piles,  32. 
sizes  of  cross-timbers  in  footings,  70. 
steel    reinforcement   in   concrete  spread 

footing,  53. 
T-beams,  reinforced  concrete,  659. 
Fortifications, 
concrete,  595. 

Portland  cements,  use  of,  171. 
Foundation,  Foundations, 
area  steps,  level  of,  114. 
bearing  power  of  soils,  10. 
blue  clay,  trench  outside  wall,  8. 
brickwork,  311. 
caisson,  74. 

cantilever  construction,  83. 
cement  walks,  117. 
clay,  4. 

firm  soils,  7. 

with  stone  drains,  8,  Fig.  6. 
compressible  soils,  25. 
concrete,  for  engines,  595. 
continuous,  versus  piers,  14. 
concrete,  mass,  622. 
contract  for,  24. 
defective,  5. 

depth  of,  city  buildings,  14. 
designing,  13. 
filled  in  ground,  4,  9. 
footings  on  sand,  9. 
furnace,  specifications,  828. 
gravel,  4. 

heavy  blue  clay,  firm  soils,  7. 

high  buildings,  83. 

importance  of,  5. 

light  buildings,  3. 

loam  and  made  land,  9. 

made  land,  use  of  piles,  9. 

mud  and  silt,  9. 

nature  of  soils,  3. 

new,  placed  under  old,  123. 

partly  on  rock,  6. 

Portland  cements,  wet  places,  170. 

removal  of,  shoring,  120. 

roadway  pavements,  concrete,  595. 

rock,  4. 


rock  and  soils,  safe  bearing  strengths  of, 
10.  , 
dififerent  levels,  6. 
excavations,  5. 
footings  on,  5. 
surface  water,  5. 
rubble,  use  of  lime  and  natural  cement 

mortars,  136. 
sand,  4. 

settlements  in,  303. 

settling  unequally,   different  levels,  6. 
silt  and  mud,  9. 

soils,  borings  to  test  character  of,  4. 
sustaining  power  of,  4. 

spread,   (see  spread  foundations). 

soils  of  peculiar  nature,  10. 

stonework,  311, 

superintendence  of,  23,  106. 

temporary  building,  70. 

test  borings,  for  original  soil,  4. 

usual  practice  in  building,  97. 
Foundation  bed, 

of  gravel,  9. 

of  rock,  foundation,  5. 

of  sand,  how  considered,  9. 

partly   on    rock,    partly   on   soil,    to  be 
avoided,  6. 
Foundation  stones,  porosity,  96. 
Foundation  walls   (see  walls,  foundation). 
Four-centered  arches,  287. 
Frames, 

door  partitions,  tile,  548. 

window,  fire-proof,  541. 
and  door,  metal,  582. 
France, 

natural  cements,  141. 

Portland  cements,  163. 
Freezing, 

of  clay  to  outside  of  foundation  wall, 
how  to  prevent,  8. 

test,  concrete  blocks,  867. 
Freezing  weather, 

brickwork,  laying,  339. 

effect  on  clay  soils,  7. 

grouting,  337. 

laying  concrete  in,  602. 
masonry   in,  831. 

pointing  joints  in,  302. 
Friezes, 

stone,  292. 
Frieze-courses,  bricks,  colored,  346. 
Frost, 

effect  of,  on  gravel  foundation  bed,  9. 

mortar,   lime,  339, 
cement,  340. 
Frost  line, 

depth  of,  foundations,  7. 

effect  on  clay  soils,  7. 

level  of  footings,  relative  to,  113. 

wall  supporting  pavements,  117. 
Frost  resistance,  bricks,  sand-lime,  332. 
Fugman,  G.,  Berger  corrugated  steel  plate, 
514. 

Full-glazed  terra-cotta,  407,  408. 
Furnace,  fire-brick  lining,  324. 
Furnace  foundations,  specifications,  828. 
Furring, 

architectural  forms,  573. 
ducts,  573.  575- 
fire-proof,  bricks,  hollow,  569. 
general  considerations,  569. 
metal  strips,  570. 
tile,  569. 

metal,  555,  556,  S7o,  572,  573,  574,  575. 
allunited  steel  side-slot  furring  studs, 

571.  574. 
architectural  forms,  576. 


938 


INDEX. 


Furring  Blocks— Gravel. 


beams,  false,  470. 
channel-block  furring,  571,  572. 
cdtnice  profiles,  575,  576,  577. 
false  construction,   573,   576,  577. 
prong  lock  wireless  steel  furring,  571, 
475- 

rib-lath    triangular    expanded  furring 

studs,  571,  573. 
Roebling  V-rib,  571,  572. 
specifications,  839. 

steel  beams  and  girders,  575,  576,  577. 
V-rib,  571,  572. 

White    system    for    walls,    pipes  and 
ducts,  571,  575. 
pipes  in  walls,  573,  575. 
reliance  steel,  columns,  454. 
Etone  backing,  299. 

tile,  beams,  833.  * 
cornices,  833. 
false  beams,  833. 
walls,  833. 
Furring  blocks,  brick  walls,  374. 

G 

Gable  copins,  292,  309,  310. 

Gabriel  Concrete  Reinforcement  Company, 

Detroit,    Mich.,    concrete,  reinforced, 

type  of  construction,  710. 
Gabriel  Concrete  Reinforcement  Company, 

Detroit,  Mich.,  designing  tables,  649. 
Gabriel  system   (see  concrete,  reinforced), 

709. 

Galvanized-iron, 
anchors,  300. 

crown-molds  for  brick  cornices,  344. 
clamps,  stone  columns,  292. 

stone  voussoirs,  284,  285. 
Gas  pipes,  floors,  fire-proof,  470. 
General    Fire-proofing   Co.,   allunited  steel 

furring  studs,  571,  574. 
General    Fire-proofing    Co.,  Youngstown, 

Ohio,  cold-twisted  lug  bar,  680. 
General  Fire-proofing  Co.,  column  furring, 

454. 

General    Fire-proofing    Co.,  corner-beads, 

universal  steel,  565. 
General    Fire-proofing    Co.,  Youngstown, 

Ohio,  pin-connected  girder  frame,  691. 
General    Fire-proofing    Co.,  Youngstown, 

Ohio,  steel  studs,  556. 
Geological  record  rocks  of  earth's  surface, 

214. 

Georgia,  cement,  hydraulic  cement  analysis, 
145. 

Georgia,  natural  cements,  143. 
Germany,  bricks,  sand-lime,  329. 
Germany,  Portland  cements,  163. 
Germany,   Portland   cements,    dry  process 

manufacture,  167, 
Girders, 

arch  (see  arch-girders), 
bearing,  295. 
false,  470,  573,  574,  576. 
fire-proofing,  531,  532,  533. 
concrete,  533. 
general  considerations,  530. 
iron,  747. 

latticed   concrete,    reinforced,    720,  721, 
722. 

plate,  cantilever  foundation  construction, 
85. 

foundation,  Manhattan  Life  Ins.  Bldg., 
N.  Y.,  79. 
Steel,  747. 

furring  for  molded  profiles,  575,  576, 
577- 

wire  lath  covered,  841. 


wood,  shrinkage,  295. 
Gladding,  McBean  &  Co.,  327. 
Glass,  wire  (see  wire-glass). 
Glazed  bricks  (see  bricks,  glazed). 
Glens  Falls,  N.  Y.,  limestone  columns,  ,305. 
Gneiss,  215. 

Goetz  box  anchors,  356,  357. 

Golding  bars,  reinforcements,  concrete  col- 
umns, 700,  701. 

Golding  bars   (see  concrete,  reinforced). 

Goodrich,  E.  P.,  forms,  wood,  in  concrete 
construction,  621. 

Gothic, 

arches,  287. 

stone  tracery,  298,  299. 
Gothic  architecture,  label  molds,  284. 
Government  buildings,  stone  stairs,  293, 

classification,  stone  for  building,  206. 

printing  office,  Washington,   D.  C,  fire- 
proof floors,  465. 
Government  stone-cutting,  274. 
Grade  marks,  superintendence  of,  24. 
Grading,  specifications,  816. 
Granites, 

absorption,  ratio  of,  881,  883,  891. 

chemical  composition,  884. 

Connecticut,  222. 

defects  in,  308. 

description  of  important,  216. 

dressing,  271,  274, 

axe  or  peen-hammer,  270. 
finish,  273,  274. 
fire-proof  construction,  440. 
general  description,  213. 
heat-resistance,  891. 
knots  in,  308. 
Massachusetts,  221. 
Maine,  216. 
Missouri,  225. 
modulus  of  rupture,  305. 
New  Hampshire,  223. 
North  Carolina,  224. 
production,  1896-1906,  205,  206. 
production,  1905-1906,  value  of,  878,  879. 
Ilhode  Island,  224. 
rock-faced  ashlar,  cost  of,  271. 
sap,  308. 

specific  gravity,  883. 

specifications,  821. 

stains  in,  308. 

strength,  crushing,  881,  883. 
safe  bearing,  10.    Table  I. 

various  districts,  226. 

Vermont,  220. 

weight,  881,  883,  891. 

Wisconsin,  225. 
Granite  blocks,  measurement  of,  306. 
Granite  buildings,  lists  of,  887,  889,  890. 
(iranite  columns,  305. 
Granite  hard  wall  plaster,  787,  789. 
Granite  rock,  safe  bearing  strength  of,  10. 
Granite  stairs,  293. 
Granite  sills,  274. 
Granite  steps,  274,  293. 
Granite  walls,  foundation,  819. 
Grant,   John,   English   engineer,   tests  and 

use  of  Portland  cements,  163. 
Granular  limestones  (see  limestones,  granu- 
lar). 

Granular  marbles  (see  marbles,  granular). 
Grappier  cement,  Lafarge  cement,  138.  See 

limes,  hydraulic). 
Grates  for  fire-places,  389. 
Gravel, 

concrete  blocks,  730,  731. 

foundations,  4. 

foundation  bed,  9. 


INDEX. 

Grillagre — Hotels. 


939 


strength  safe  bearing,  lo.    Table  I. 
with  clay,  foundations,  firm  soils,  8. 
roofing,  536,  539. 
Grillage, 

steel  I-beam  under  columns,  717. 
steel-beam  cantilever  construction,  85. 
timber,  water  line,  38, 
capping  for  wooden  piles,  38. 

heavy  floor  to  receive  footings,  38. 
steel-beam,  expense,  39. 
timber,  38. 

advantages,  38. 
distribution  of  pressure,  38. 
footings,  see  steel-beam  footings,  58. 
Ground,  filled  in,  foundations,  4. 
Grounds, 

metal  and  plaster  partitions,  557,  558. 
tile  cornices,  577,  578. 
Grout,  192. 

brickwork,  92,  335..  337- 

brickwork,  specifications,  827. 

floor  arches,  brick,  467. 

hollow  concrete  block  columns,  699. 

local  conditions,  192. 

mixing,  193. 

on  steel  floor-beams,  471. 

use  of,   recommendation,  192. 
Guaged  brick  arches,  380. 
Guastavino  Company,  R.,  New  York,  tile 
arch,    vault    and    dome  construction, 
^  496. 

Guastavino,  tile,  495. 

tile  arch  construction,  domes,  recent  typi- 
cal large,  497. 
vault  and   dome  constructions,  advan- 
tages, 497. 
examples,   496.  ' 
vault  and  dome  construction,  strength, 
496. 
stairs,  580. 
Gutters,  behind  retaining  walls,  104, 
Gussets,     concrete,     reinforced,  specifica- 
tions, 859. 

Gutters,  copper  for  brick  cornices,  343. 
Gypsum, 

Nova  Scotia,  788. 

partition  blocks,  545. 
Gypsinite   Company,   New   York,  partition 

blocks,  545. 
Gypsite  partitions,  545. 
Gypsite  tile  column  coverings,  459. 


Haddonfield,  N.  J.,  bricks,  sand-lime,  329. 
Hair  for  plastering  mortar,  778,  779. 
Hammer, 

use  in  driving  corrugated  concrete  piles, 
44. 

drop  (see  drop  hammer). 

steam   (see  steam  hammer). 

dressed  joints  and  beds,  264. 

for  stone  dressing,  271. 
Hammered  brass  stone  dressing,  275. 
Hand-made  bricks,  313. 
Hanging  stairs,  294. 
Hard  wall  plaster  (see  plaster). 
Hardness, 

bricks,  312. 

stones  for  building,  255. 
Hatt,  W.  K.,  mortars  impervious  to  water, 

196. 
Haunches, 

floor  arches,  brick,  466. 

filling,  477. 
stone  arches,  281. 
Haverstraw  size  bricks,  473. 
Haydonville  Company,  Ohio,  floor  arches, 
tile,  481. 


Heat, 

resistance  bricks,  enamelled,  322. 

sand-lime,  332. 

concrete,  603. 
stones,  effect  on,  891. 
Heat-resistance, 

concrete  block  walls,  732. 
fire-brick,  332. 

floor  arches,  reinforced  tile,  494. 
flooring,  534. 

floor  arches,  Johnson  arch,  490. 
granites,  891. 

Kiihne's  truss  metal  lath,  559. 
limestones,  891. 
marbles,  891. 

metal  lath  and  plaster,  774. 

partitions,  541. 

metal  and  plaster,  550. 
plaster-block,  543. 

plaster  boards,  548. 

reinforced  concrete,  tests,  723. 

roofing,  536. 

roofs,  535. 

sandstones,  891. 

slate,  536. 

stone,  579,  891. 

tiles,  clay,  536. 

stones  for  building,  256. 

terra-cotta,  architectural,  434. 

wall  facing,  released,  592. 

walls,  curtain,  fire-proof  buildings,  754. 
Heavy  buildings, 

built  on  gravel,  foundations,  9. 

Colorado,  footings,  how  laid,  8. 

footing  trenches,  24. 

footings  for,  90, 

on  clay  soils,  danger  of,  7. 

trenches  for,  24. 
Heavy  rubble,  89. 
Height, 

stones  in  broken  ashlar,  265,  266. 
non-fire-proof  buildings,  438. 
Heights    of    stories,    mercantile  buildings, 
362. 

Hemlock,  for  boxing  stonework,  stains,  301. 
Hennebique    concrete     column  reinforce- 
ment, 695. 

Hennebique  system  of  reinforcement  (see 

concrete,  reinforced). 
HerringbSne  expanded  metal  lath,  564,  565, 

566. 

Herculean  reinforced  tile  floor  arch,  493, 
494.  495. 

High  calcium  limes,  128. 

High  carbon  system  concrete,  reinforced, 
type  of  construction,  704,  705. 

Hinchman-Renton  Fire-proofing  Co.,  col- 
umns, fire-proofing,  452,  453,  456. 

HinChman-Renton  Fire-proofing  Co.,  Den- 
ver, Colo.,  concrete  columns,  rein- 
forced, 697. 

History  reinforced  concrete  construction, 
632. 

Hoisting  engines,  cause  of  stains  on  plas- 
tered ceilings,  469. 
Holes,  in  rock,  foundations,  6.     Fig.  5. 
Hollow  brick  wall  furring  (see  furring). 
Hollow  bricks    (see  bricks). 
Hollow  concrete  I-arch.  527,  t;28,  529. 
Hollow  walls  (see  walls,  hollow). 
Honeycombed  dressed  stonework,  275. 
Hoop-iron  bond  brickwork,  354. 
Hose  reels,  582. 
Hospitals, 

brick  facing,  glazed  and  enamelled,  32*. 

walls,  thickness  of,  908. 
Hot  weather,  pointing  joints  in,  302. 
Hotels, 


940 


INDEX. 

Housing — Joints. 


computing  the  weight  on  footings,  i6. 

walls,  thickness  of,  908. 
Housing,  walls  together,  302. 
Hydrochloric  acid,  cleaning  stonework,  302. 
Hydrated  lime  (see  lime  hydrated). 
Hydrous   lime   silicate   bricks,   sand  lime. 

Hydraulic  limes   (see  limes,  hydraulic). 


I-Arch  sectional  concrete  floors  (see  floors, 

fire-proof). 
I-Beam  lintels,  747. 
"Ideal"  tile  fire-proof  column,  449. 
Igneous   slates,  898. 

Illinois,  La  Salle,  hydraulic  cement  analy- 
sis, 145. 

Illinois,  natural  cements,  142. 

Illinois,  Utica,  hydraulic  cement  analysis, 
145- 

Imitation  marble,  796. 

"Imperial"  expanded  metal  lath,  565,  567. 
Imperial    Expanded  "  Metal    Co.,  Chicago, 
111-,  565. 

Improved  natural  hydraulic  cements,  mix- 
tures of  Portland  and  natural  cements, 
191. 

Impost  courses,  brick,  341. 
Inclined  layers,  clay  soils,  7. 
India, 

grouting,  193. 

sugar  in  lime  mortar,  197. 
Indiana, 

natural  cements,  142. 

limestone,  227,  228,  229 
Inspection, 

(see  also  superintendence). 

footings,  108. 

foundation  walls,  thoroughness,  108. 
foundations,  23. 
mason's  materials,  108. 
sand,  132. 

stonework  already  erected,  108. 

terra-cotta,  architectural,  412. 
Interior  finish,  fire-proof,  578. 
Intrados,  arches,  281. 
Inverted  arches, 

areas  proportional  to  load,  94. 

distribution  of  weight,  93.  ^ 

example  in  calculation,  95.  ^ 

footings  for,  94. 

load  on,  95. 

material,  94. 

mortar,  94. 

objections  to,  93. 

on  soft  soils,  94. 

sectional  area  of,  95. 

skewbacks  for,  94. 

thickness  of  arch  ring,  95. 

use  of,  95. 
Iron,  color  of  bricks,  325,  326. 
Iron  anchors  (see  anchors,  iron). 
Iron  ballusters,  stone-stairs,  294. 
Iron  girders  (see  girders,  iron). 
Iron  lintels  (see  lintels,  iron). 
Iron  newells,  stone  stairs,  294. 
Iron  oxide,  brick  manufacture,  312. 
Iron    pins,    fixing    lot    lines,    staking  out 

buildings, _  3. 
Iron  pyrites  in  sand-stones,  237. 
Iron  railings,  stone  stairs,  294. 
Iron  stairs,  580. 

Iron  supports  for  masonwork,  747. 
Iron  ties,  stone  entablatures,  292. 
Iron  ties,  stone  voussoirs,  284,  285. 
Ironwork, 

setting  specifications,  829. 

skeleton  construction,  768. 


wire  lath  covered,  841. 
Irregular  coursed  ashlar,  265. 
Isolated   buildings,    designing  foundations, 

13. 
Italy, 

brickwork,  ornamental,  340. 
Pozznoli,    origin    of   Puzzolan  cements, 
180. 


Jackson,   Peter   H.,    San   Francisco,  Cal., 
earthquake  resisting  construction,  587. 
Tackscrews,  to  take  up  settlement,  123. 
Jails,  walls,  thickness  of,  910. 
Jambs, 

brick,  267. 
Jambs, 

door  and  window  concrete  blocks,  746. 

interior  door,  tile,  molded  hollow,  578. 

rubble  walls,  264. 

stone,  size  of,  266. 

cutting  and  rubbing,  267. 

terra-cotta,  835. 

window,  stone,  267. 
Jambs  and  quoins,  266. 
Jamb-stones, 

bond,  267. 

drawings  for  in  ashlar,  296. 

Joggled  joints,  288. 

Johnson  bar,  pulling-out  tests,  666. 

Johnson  bar  reinforcing  system  (see  con- 
crete, reinforced). 

Johnson  corrugated  bar  (see  concrete,  rein- 
forced). 

Johnson,  Prof.  J.  B.,  American  and  Euro- 
pean natural  cements,  144. 

Johnson,  Prof.  J.  B.,  natural  cements,  non- 
uniformity  of  hardening,  148. 

Johnson  tile  floor-arches,  477,  481,  490,  492, 

^  .  .583. 

Joining,  new  and  old  brick  walls,  360. 
Jointer, 

pointing  stonework,  302. 

ruled  joints,  brickwork,  338. 
Joints, 

ashlar,  thickness,  298. 

bed  (see  bed-joints), 

between  stone  sills  and  brickwork,  280. 

brick  backing,  299. 

brick  backing-arches,  285. 

brickwork,  352. 

built-up  arches,  284. 

close,   laying   lower  level   rock  founda- 
tions, 6. 

composite  stone  lintels,  279. 

compression  in  mortar,  303. 

concave,  in  stonework,  302. 

convex,  cut  stonework,  298. 

cut  stonework,  296. 

elliptical  arches,  286. 

false,  lintel-arch  of  stone,  289. 
in  stone  voussoirs,  283. 

flat  arches,  289. 

floor  arches,  tile,  end-construction,  484. 

tile,  side-construction,  479. 
foundation  walls,  pointing  below  grade, 
24. 

gable  copings,  293. 
hammer-dressed,  264. 
hollow,  cut  stonework,  296,  298. 
joggled,  288. 

label-molds,  arch-rings,  284. 
masonry,  compression  of,  278. 

undressed,  264. 

width,  264. 
moistening  before  pointing,  302. 
mortar  bricks,  pressed,  327. 

brickwork,  335. 


INDEX. 


941 


Joist-Iiang:ers— Laying:. 


thickness,  335. 
columns,  stone,  305. 
diips,  337- 

face  joints  in  cut-stone,  310. 
plaster  in  brickwork,  337. 
radial  block  chimney  construction,  325. 
ruled,  338. 

ruling  to  hide  distortion,  342. 

stone  columns,  304. 

striking  in  brickwork,  337. 

thickness  of,  in  brickwork,  335. 

washing  out  by  rain,  340. 
open  under  relieving-beams,  285. 
pointing  in  freezing  weather,  302. 
pointing  in  hot  weather,  302. 
taking  out,  300. 
raised,  false  joints,  263. 

in  stonework,  302. 
rusticated,  298. 

shrinkage  in,  in  brick  backing,  299. 

slack,  cut  stonework,  298. 

slip  (see  slip-joints). 

stone  columns,  291,  292. 

stone  entablatures,  292. 

stone  sills,  298. 

stone  tracery,  298,  299. 

stonework,  cutting  for  broken  ashlar,  265. 

length  of,  265. 

sunk  or  bevelled,  274. 
struck,  338. 

terra-cotta,   architectural,   412,  413,  414, 
415,   416,   417,   418,   419,   420,  421. 

thickness  in  stone  piers,  304. 

underpinned  cut-stonework,  298. 

vertical,  in  flat  stone  arches,  289. 
stone   walls,  99. 

voussoirs  of  stone  arches,  281,  282. 
Joist-hangers,  concrete  block  walls,  745. 
Joist  supports,  concrete  block  walls,  745. 
Joists, 

wooden,  on  brick  corbells,  358. 

supports  in  concrete  block  walls,  740, 
741. 

K 

Kahn  trussed  bar, 

column  reinforcement,  699. 

reinforcement    for   concrete,  51. 
Kahn  bar  (see  concrete,  reinforced). 
Kaolin, 

brick  manufacture,  glazed,  320. 
bricks,  sand-lime,  331. 

Kansas,  Fort  Scott,  hydraulic  cement  analy- 
sis, 145. 

Kansas  natural  cements,  143. 

Karbolith,  flooring,  534. 

Keene's  cement  (see  cement). 

Kentucky,  _  Louisville,  hydraulic  cement 
analysis,  145. 

Kentucky  natural  cements.  142. 

Ketterlinum  building,  Philadelphia,  Pa., 
concrete,  reinforced  construction,  715, 
716,  717,  718. 

Keys, 

floor  arches,  tile,  484. 

for  mortar,  bricks,  338. 

tile  floor  arch,  types  of,  474,  475. 
Keystones,  284. 

flat  stone  arches,  288. 

stone  arches,  281. 
Kilns, 

bee-hive,  319. 

brick,  318. 

clay  wares,  319, 

continuous,  320. 

vertical,  mixed-feed  for  burning  lime- 
stone, 127. 


down-draft,  319. 

for  Portland  cements,  167. 

pottery,  319. 

terra-cotta,  319,  406. 

up-draft,  318. 

used  in  production  of  lime,  common,  127. 
King's  Superfine  Windsor  Cement,  795. 
King's   Windsor  cement,   dry  mortar,  787. 
788. 

Kneelers,  gable  copings,  293. 
Knots,  granites,  308. 

Kiihne's  clincher  sheet-metal  lath,  558,  567, 
568. 

Label-moldings,  284. 

Gothic  architecture,  284. 
Label-molds,  Renaissance  architecture,  284. 
Laboratories,  walls,  thickness  of,  908. 
Ladders,  for  chimney  interiors,  771. 
Lafarge  cement  (see  cement,  Lafarge  and 

limes,  hydraulic). 
Laminated  stone   (see  stone,  laminated). 
Land,  made,  foundations,  9. 
Larned,  E.  S.,  cement  bricks,  334. 
Lath, 

expanded-metal,  562. 

"Imperial,"  565,  567. 
furred  stone  backing,  299. 
metal,  774. 

ceilings,  suspended,  540. 

corrosion,  550. 

different  kinds,  559. 

Kiihne's  truss  metal  lath,  558,  559. 

miscellaneous  forms,  569. 

partitions,  solid,  842. 

specification,  836. 

where  used,  776. 
perforated  sheet-metal,  566. 

P>ostwick,  566,  567,  568. 

Kiihne's  clincher  lath,  567,  568. 

rib  lath,  568. 
rib  (see  rib  lath), 
sheathing,  773. 
wire,  561. 

Clinton,  561,  562,  563. 

column  covering,  841. 

furring  for  architectural  forms,  576. 

on  brickwork,  840. 

on  metal  furring,  839. 

on  ironwork  and  steelwork,  841. 

on  woodwork,  840. 

partitions,  solid,  842. 

Roebling,  562,  563. 

steel  girder  covering,  841. 

stiffened,   561,   562,  563. 
specifications,  840. 

unstiffened   or   plain,    561,  563. 
wooden,  773. 

specifications,  836. 
Lath-and-plaster, 

fire-proofing,  columns,.  449. 
measuring,  805. 
Lathing  and  plastering, 

fire-proof  construction,  804. 
general   considerations,  772. 
superintendence,  809. 
Lathing,  cost  of,  806. 
Lavastones,  247,  250. 
Laws,  building  (see  building  laws). 
Laying  bricks,  336.  ' 
floor  arches.  467. 
freezing  weather,  339. 
Laying  concrete,   freezing  weather,  602. 
Laying, 

concrete   in   freezing   weather,  specifica- 
tions, 859. 


942 


INDEX. 

Liaying  Out  Cut-stonework — Limestones. 


concrete,    warm    weather,  specifications, 
859. 

Laying  out  cut-stonework,  275. 
Lead  flashing,  342. 

Le  Chatelier,  H.,  composition  of  Portland 
cements,  167. 

Lee  end-method  tile  floor  arch,  480,  481. 

Lee,  Mass.,  marble  columns,  305. 

Lee,  Thomas  A.,  floor  arches,  tile,  480. 

Level  beds,  use  of  concrete,  rock  founda- 
tions, 5. 

Level  footings,  building  on  rock,  founda- 
tions, 6. 

Level  planes,  cut  in  rock,  foundations,  5. 
Levels, 

different,  rock  foundations,  6. 

trench  bottoms,  24. 
Libraries,  walls,  thickness  of,  910. 
Light  buildings, 

footings  for,  89. 

foundations,  3. 

ordinances  for  footings,  18. 
Light-courts,  facing,  terra-cotta. 
Light-house, 

foundations,   concrete,  611. 
.walls,  thickness  of,  910. 
Lignolith,  flooring,  534. 
Lime,  Limes, 

affect  on,  color  of  bricks,  325,  326. 

in  concrete  blocks,  730. 

in  paving  bricks,  323. 

in  pointing  putty,  302. 

in  sand-lime  bricks,  329. 

in  slates,  895,  896. 

common,  127. 
air  slacked,  135. 

amount  of  water  required  for  slaking, 
130. 

commercial   quantitive  values,  128. 
composition  of  limestones,  127. 
characteristics  of  good,  129. 
•chemistry  of  burning,  128. 
■classification  for  commercial  purposes, 
128. 

difference  in  various  localities,  128. 
fat  or  rich  lime,  128. 
freedom  from  impurities,  129. 
fresh   burned,  effect  of  moisture  on, 
135- 

fuel  for  burning,  127. 
■high  calcium,  128. 

keeping  qualities  with  reference  to  cli- 
mate, 129. 
kilns  for  burning,  127. 
lean  or  poor  lime,  128. 
leaving  residue,  130. 
location  of  manufactories,  128. 
magnesia  not  an  impurity,  127. 
magnesian,  128. 
marble  for  production,  127. 
mortar,  making  of,  129, 
non-hydraulic,  139. 
paste  or  putty,  133- 
paste,  keeping  qualities,  133. 
plasticity  of   magnesian   limes,  128. 
preserving  of,  135. 
production,  127. 
properties,  127. 

proportions  of  sand  for  mortar,  130. 

protection  of,  before  use,  135. 

pure,    avoidance   of   in  constructional 

work,  135. 
quality,    dependence    upon  impurities, 

127. 

quality  for  common  mortar,  128. 

plastering,  128. 
<iuantitive      equivalents     for  stone, 
brick,  plastering,  etc.,  129. 


residue,  129. 

solubility  in  water,  129. 

slaked,  covering  till  needed,  129. 

slaking,  129. 

of  magnesian  limes,  128. 
specific  gravity,  127. 
strength  of  magnesian  limes,  128. 
volume  after  slaking,  130. 
weight  per  barrel,  129. 

per  bushel,  129. 

per  cubic  foot,  129. 
white  chalk  for  production,  127. 
high  calcium,  128. 

in  sand-lime  bricks,  329, 
hydrated  and  Portland  cement,  strength 

of,  tests,  131. 
bricks,  sand-lime,  331. 
manufacture,  131. 
ready  slaked,  131, 
hydraulic,  136. 
analysis  of,  137. 

Lafarge  cement,  139. 
artificial,  138. 

comparison    with    Portland  cement. 
138. 

brickwork  below  ground,  335. 
color  of  Lafarge  cement,  201. 
clay,  silica,  136. 

composition  of  limestone  for  Mr.  Ed- 
win C.  Eckel,  136. 

determination  of  hydraulicity,  138. 

eminently  hydraulic,  136. 

feebly  hydraulic,  136. 

general  description,  136. 

"grappier  cement,"  by  product,  137. 
by   product   of   calcination    of  emi- 
nently, hydraulic  limes,  137. 

hardening  under  water,  136. 

Lafarge  cement,  138. 
non-staining,  138. 

non-staining    cements,    139,  specifica- 
tion for,  139. 

rejection  after  first  setting,  136. 

•'selenitic    lime,"    treatment    with  sul- 
phuretic  acid,  137. 

setting  of,  136. 

setting  work  with  Lafarge  cement,  138. 
suitable  limestones  for,  138. 
use  in  United  States,  138. 
selenetic,  plaster  of  Paris  and  hydraulic 
lime,  197. 
Scott's  cement,  137. 
treatment  of  hydraulic  lime  .with  sul- 
phuretic  acid,  137. 
Lime  and  sugar,  solubility  in  water,  197. 
Lime,   cement   and  mortar,   importance  of 

subject,  127. 
Lime  hydrate,  129. 

in  sand-lime  bricks,  331. 
Lime  magnesia,  in  bricks,  312. 
Lime-sand  bricks  (see  bricks,  sand-lime). 
Limestones, 

absorption,  ratio  of,  881,  882.  891. 
calcination  of,  producing  common  lime, 
127. 

chemical  composition,  885. 
composition  of,  127. 
coursed-ashlar,  264. 
description  of  important,  227. 
dressing,  270,  271. 
finish,  272,  273,  274. 
fire-proof  construction,  440. 
for  Portland  cements,  166, 
general  description,  226. 
heat-resistance,  891. 
lumps  of  in  brick-clay,  312. 
modulus  of  rupture,  305. 
production,  1896-1906,  205,  206. 


INDEX. 

Lilmestone—— Marble. 


943 


in  1905  and  1906,  value  of,  878,  879. 
specific  gravity,  883. 
strata,  146. 

strength,  crushing,  881,  882,  883. 

strength  safe  bearing,  10.     Table  I. 

weight,  881,  882,  883,  891. 
Limestone  ashlar  (see  ashlar,  limestone). 
Limestone  buildings,  lists  of,  887,  889,  890. 
Limestone,  coquina,  127. 
Limestone,  Glens  Falls,  N.  Y.,  columns,  305. 
Limestone,  granular,  stains,  301. 
Limestone,   Indiana,  columns,  305. 
Limestone,  oolithic,  127. 
Limestone  walls,  foundations,  819. 
Limoid,  hydrated  lime,  131. 
Line,  frost,  effect  on  clay  soils,  7. 
Lines, 

t  building,  I. 

cut  on  curbstone,  staking  out  buildings, 
3. 

staking  out  city  buildings,  3. 
excavations  carried  beyond,  24. 
lot,  3. 

party,  staking  out  buildings,  3. 
street,  staking  out  buildings,  3. 
use  of,  in  staking  out  buildings,  3. 
where  set,  staking  out  buildings,  3. 
building,  superintendence  of,  23. 
Linings, 

basement    walls,     for    protection  from 

dampness,  iii. 
chimney,  brick,  324. 
flue,  828. 
Lintel,  Lintels, 
cast-iron,  360. 

concrete  block  construction,  864. 
concrete,  reinforced,  718,  742,  859,  864. 
iron,  747. 
steel,  747. 

steel,  skeleton  construction,  760. 
stone,  277. 

bearings,  279,  289. 

building  ends  into  walls,  278,  279. 

built  up,  289. 

composite,  279. 

cracking  and  breaking,  cause  of,  278. 
imitating  flat  arches,  289. 
natural  bed,  306. 
steel  supports  for,  279. 
strength  of,  305. 
supports,    278,  289. 
weathering,  278. 
terra-cotta,  steel  supports,  759,  760,  761, 

762,  763,  764. 
wooden,  brick  walls,  364,  382. 
Lintel  tile  floor  construction,  487. 
Live   loads,   settlements,   unequal,  founda- 
tions, 16, 

Liverpool,    England,    Mersey    docks  and 

warehouses,  grouted  brickwork,  337 
Loads, 

brickwork,  safe  loads,  907. 
cement  bricks,  334. 
columns,  719. 

concrete,  reinforced,  668,  717, 

stone,  safe,  305. 
concrete  block  walls,  745,  863. 

safe  loads,  907. 
flagstones,  306. 
floor-arches,  brick,  467. 

segmental,    concrete,    Roebling,  501. 

tile,  reinforced,  489,  492,  493. 
segmental,  476. 
Guastavino  tile  arches,  496. 
inverted  arches,  95. 
lintels  of  stone,  305. 

live,    unequal    settlements,  foundations, 
16. 


masonry,  303. 

safe  working  loads  on,  907. 
mortars,  safe  loads  in,  907. 
partitions,  loads  on,  541. 
piers,  brick,  311,  402. 

brick,  safe  loads,  907. 
stonework,   safe  loads,  907. 
tiles,  hollow,  safe  loads,  907. 
walls,  brick,  safe  loads,  907. 
Loam, 

foundations  on  firm  soils,  9. 
how  treated  under  foundations,  9. 
Lock-woven  fabric   reinforcement   (see  re- 
inforcements). 
Lofts,  floor  arches,  segmental,  472. 
Loads, 

stone  piers,  safe,  304. 
stone  walls,  safe,  304. 
London,    Westminister    Cathedral,    use  of 

Portland  stone,  163. 
Longmeadow,    Mass.,    sandstone  columns, 

305. 
Lot  lines,  3. 

Lot,   party-lines,   staking  out  buildings,  3. 
Lower  level,  footings,  laid  in  cement  mor- 
tar, 6. 

Lug  bar,  cold-twisted   (see  concrete,  rein- 
forced) . 
Lug  sills,  280. 
Lumber,  scarcity  of,  311. 

M 

"M"   system    (see  concrete,  reinforced). 
Machine-made  bricks,  313. 
Machine-made    mortar    (see    mortar,  ma- 
chine-made). 
Machine-shops,  walls,   thickness  of,  910, 
Machinery, 

brick  manufacture,  313. 

concrete  mixing,  597. 

foundations,  concrete,  595. 
Machines, 

concrete  block  manufacture,  744. 

preparing  clay  for  bricks,  313. 

pressing,  brick  manufacture,  316,  317. 

stiff-mud  brick  manufacture,  315. 
Mackolite  Fire-proofing  Co.,   Chicago,  111., 

partitions,  545. 
Mackolite  partition  tile.  545. 
Made  ground,  4. 

footings  on,  foundations,  9. 

foundations,  9. 

overlying  firm  earth,  how  handled,  foun- 
dations, 9. 
Magnesia  bricks,  paving,  323. 
Magnesia  building  lumber,  flooring,  534. 
Magnesia  hydrates,  bricks,  sand-lime,  331. 
Magnesian  limes, 

in  bricks,  312. 

slaking  of,  128. 
Magnesian  limestones,  227. 
Magnesian  silicate,  bricks,   sand-lime,  331. 
Magnesite,  flooring,  534. 
Magnesium  chloride,  flooring,  534. 
Magnitite  slates,  amount  of  magnitite,  893. 
894- 

Maine,   eastern,   clay  soil,   depth   of  frost 

line,   foundations,  7. 
"Manitou,  Colo.,  sandstone  columns,  305. 
Mansard  roofs  (see  roofs). 
Mantels,  fire-place,  391,  392,  393,  394,  395. 
Afanufactured  stone,  260. 
ATanufacture  of  bricks,  313. 
Afanle  flooring,  718. 
Alarb^e, 

absorntion,  ratio  of,  881,  891. 
rhen-iiral  romnosi'tion,  885. 
description   of   different   kinds,  233. 


944 


INDEX. 

Marble  Ashlar — Modulus  of  Rupture. 


finishing,  273. 
general   description,  231. 
heat-resistance,  891. 
fire-proof  construction,  440. 
granular  stains,  301. 
imitation,  796. 
modulus  of  rupture,  305. 
production,   amount  and  value,    1902  to 
•     1906,  232. 

1896-1906,  205,  206. 

1905-1906,  value  of,  878,  879. 

in  1906,  232. 
strength,  crushing,  882,  883. 
use  in  production  of  lime,  common,  127. 
weight,  882,  883,  891. 
Lee,  Mass.,  columns,  305. 
Rutland,  Vt.,  columns,  305. 
!Marble  ashlar,  296. 

Marble  buildings,  lists  of,  888,  889,  890. 
Marble  dust,  in  Lafarge  cement,  301. 
Marble  onyx,  235,  886. 

^larble  stair  treads  and  risers,  580,  581,  582. 
Marble  wall  facing,  released,  590. 
Marblework,  cleaning,  302. 
Margin   draft  lines, 

stone-arches,  282. 

stones,   270,   271,  272. 
Market  buildings, 

brick  facing,  glazed  and  enamelled,  322. 

walls,  thickness  of,  910. 
Marks,  bench,  i. 
INIarshy  soils,  foundations,  9. 
Maryland,    Cumberland,    hydraulic  cement 

analysis,  145. 
Masonry  dams,  Portland  cements,  use  in, 
171. 

Masonry  wells, 
arrangement,  72. 
Chicago  Stock  Exchange,  72. 
'City  Hall,  Kansas  City,  Mo.,  71. 
comparison  with  piles  or  spread  footings, 

economy,  71. 
excavation,  72. 
filling  around  beams,  72, 
loading,  74. 
reinforced  piers,  72. 
sheet  piling,  73. 

support  for  heavy  buildings,  71. 

system  of  transmission  of  weights,  72. 
Mason  safety  treads,  860. 
Masonwork, 

buildings,  causes  of  cracks,  15. 

expansion  and  contraction,  301. 

extra  for  too  deep  trenches,  24. 

iron  and  steel  supports  for,  747. 

laying  in  freezing  weather,  831. 

lime  mortar,  303. 

loads,  safe  working,  907. 
Mass  concrete  (see  concrete,  mass). 
Massachusetts    Metropolitan  Commissions, 

natural  cements,  specifications,  154. 
Massachusetts    Metropolitan  Commissions, 

Portland  cements,  specifications,  177. 
Materials, 

concrete  blocks,  730. 
mass,  610. 

reinforced,  properties,  643. 
selections  of.  595. 
fire-proof,  conductivity,  relative,  448. 
general  considerations,  440. 
granite,  440. 
limestone,  440. 
marble,  440. 
miscellaneous,  447. 
paint.  447. 
sandstone,  440. 
wire-glass,  447. 
wood,  fire-proofed,  447. 


reinforced  concrete  construction,  674. 

reinforced  concrete,  proportions  of,  675. 
Mat-glazed  terra-cotta,  407,  408. 
Matrix,  concrete,  594. 
Maurer  &  Sons,  Henry,  New  York, 

columns,  fire-proof,  449. 

Eureka  three-block  floor-arch,  488. 

floor-arches,  tile,  481. 

Herculean  reintorced  tile  floor-arch,  493. 

partitions,   "Phoenix,"  550. 

Phoenix  wall  tiles,  586. 
McGraw  building.  New  York,  concrete  col- 
umns with  structural  steel  cores,  719. 
Measurement, 

brickwork,  402. 

cut-stonework,  306. 

lathing,  805. 

plastering,  805. 

unit,  staking  out  city  buildings,  3. 
United  States,  standard,  staking  out  city 
buildings.  3. 
Mechanical  bond,  concrete,  reinforced,  680. 
Merrick,  Ernest,  New  York,  concrete,  re- 
inforced, floor  construction,  527. 
concrete,  reinforced,  types  of  construction, 
.  713- 

Merrick  system  (see  concrete,  reinforced 
and  also  floors,  fire-proof). 

Merriman,  Mansfield,  adhesion  of  cement 
mortar,  187. 

Mersey  Docks  and  Warehouses,  Liverpool, 
England,  grouted  brickwork,  337. 

Metal-and-plaster  partitions  (see  partitions). 

Metal  furring  (see  furring). 

Metal  lath  (see  lath,  metal;. 

Metal  wall  furring  (see  furring). 

Methods  of  testing  bearing  power  of  foun- 
dation bed,  12. 

Metropolitan  system  of  fire-proof  construc- 
tion (see  floors). 

Mica  slates,  898,  899. 

Mill  construction,  reinforced  concrete  work, 
702. 

Mills,  walls,  thickness  of,  910. 
Minerals, 

slates,  chief  minerals  in,  895,  896. 

stones  for  building,  211. 

zeolitic  group,  sand-lime  bricks,  331. 
Mining,  clay  for  bricks,  313. 
Minnesota,     Mankato,     hydraulic  cement 

analysis.  145. 
Minnesota  natural  cements,  143. 
Missouri,  Kansas  City,  City  Hall,  masonry 
wells,  71. 

Mitchell,  Mr.  C.  F.,  chemistry  of  lime  mor- 
tar setting,  134. 
Mixing  concrete,  597. 

concrete  blocks,  731. 

reinforced,  specifications,  857. 

mass  construction,  610. 
Mixing  pans,  brick  manufacture,  316. 
Modelling,  terra-cotta,  architectural,  835. 
Modillions,  terra-cotta,  423,  765,  766. 
Modulus  of  elasticity,  concrete,  600,  601, 
660. 

concrete,  reinforced  design,  660. 
ratio,  steel  and  concrete,  660. 
steel,  660,  679. 

high  carbon,  678. 

reinforced  concrete,  660. 
Modulus  of  rupture,  bricks,  common,  328. 
bricks,  paving,  323. 
bricks,  sand-lime,  332. 
bluestone  flagging,  305. 
caps,  beams  and  lintels  of  stone,  305. 
cement  bricks,  334. 
concrete  blocks,  868. 
formula  for,  in  concrete  blocks,  867. 


INDEX. 


945 


Moistening — Mortar. 


granite,  305. 

limestone,  305. 

marble,  305 

sandstone,  305. 

slate,  242,  305,  884,  897. 

tests  for,  in  concrete  blocks,  866. 
Moistening,    joints    in    stonework  before 

pointing,  302. 
Moisture, 

bricks,  glazed  and  enamelled,  322. 
sand-lime,  331. 

brickwork,  328. 

clays  for  brick  manufacture,  316. 

copings,  293. 
Molded  bricks  (see  bricks,  molded). 
Molded  work,  stone,  dressing,  272. 
Moldings, 

cut-stone,  267. 

exterior,  staining  by  dripping  water,  276. 

Keene's  cement,  578. 

stone,  compared  with  brick,  341. 

joints  in,  299. 

measurement  of,  307. 

profiles,  276. 

protecting,  301. 
Molds, 

brick  manufacture,  312,  316. 
slop-molding,  313. 
soft-mud  process,  314. 
bricks,  hand-made,  313. 
concrete  block  manufacture,  744. 
mass  construction,  611. 
Moment,  bending  (see  bending  moment). 
Moment,  resisting  (see  resisting  moment). 
Monolith   flooring,  534. 
Monolith  steel  bar,  Golding,  684,  685. 
Monolith   Steel  Company,   Washington,  D. 
C,  columns,  concrete,  Golding  bar  re- 
inforcement, 700. 
Golding  monolith  steel  bar,  684,  685. 
Morse  wall  ties,  351,  375. 
Mortar, 

abutments,  285. 

adhesion,  depending  upon  age,  195. 

upon  porosity  of  materials,  195. 

upon  sand,  195. 

upon  water  and  moisture,  195. 
brick  backing,  299. 
brickwork,  specifications,  827. 
cement,  188. 

acceleration   of   setting   by   plaster  of 
Paris,  197. 

addition  of  lime,  199. 

adherence  of  i  to  5  mixture,  191. 

adhesion  to  stone  or  brick  surfaces,  187. 

brick  arches,  285. 

brickwork,  specifications,  826. 

capacity  of  cements  for  water,  188. 

change  of  volume  in  setting,  199. 

cheapening  of,  by  adding  lime,  189. 

cold  weather  retarding  setting,  198. 

compressive  strength  ot,  186. 

covering  work  in  freezing  weather,  198. 

effect    of   expansion   and  contraction, 
199. 

estimating  quantities  of  materials,  193. 

excess  of  water,  188. 

expansion  of  its  water  in  freezing,  198. 

under  water,  199. 
experiments    for    effect    of    sugar  on 

Portland  cement  mortar,  197. 
exposure  to  weather,  188. 
flashing  brick  belt-courses,  342. 
freezing  weather,  340. 
fundamental  laws,  190. 
hand-mixing,  188. 
heat-resistance,  444. 


increase    in    strength    by    plaster  of 

Paris,  197. 
keeping  moist,  189. 

laying  lower  levels,  rock  foundations,  6. 
mechanical  mixers,  objections  to,  189. 
mechanical  mixtures,  189. 
mixing,  188. 

mixtures  of  Portland  and  Natural  ce- 
ments, 191. 

of  sand  and  cement,  189. 
natural,  188. 

effect  of  freezing,  198. 

safe  crushing  strength,  195, 

staining  stones,  301. 

use  of,  147. 
neat,    expansion    and    contraction  of, 
199. 

Portland,   advantages,  191. 
cheapness;  191. 
comparative  strength,  192. 
hydraulic  properties,  191. 
rapidity   of   setting   and  hardening, 
191. 

resistance  to  weather,  192. 
strength  on  exposure  to  air,  192. 
Portland,  188. 

absorption  of  water,  196. 

and    Puzzolan    cements,  impervious 

to  water,  196. 
bedding  steel  beams,  58. 
effect  of  freezing,  198. 
pointing  joints,  302. 
set   retarded  by  addition  of  sugar, 
197. 

staining  stones,  301. 

stone  column  setting,  304. 

strength    increased    by    addition  of 
sugar,  197. 
safe  crushing,  195. 
quantity  mixed  at  a  time,  188. 
sand,  proportions,  189. 
strength,  tensile,  185. 
superintendence,  190. 
use,  188. 

volurne   obtained   with   different  mix- 
tures, 194. 
cement-lime,  191. 

comparison  of  costs  of  Portland  and 
natural  cements,  192. 

examples  of  mixtures,  192. 

impervious  to  water,  196. 

mixing,  192. 

variety  of  uses,  191. 
color  affected  by  materials,  199. 

varying  shades  by  water,  199. 
colored,  132,  263,  346. 

pointing,  302. 

rubble  work,  263. 

specifications,  827. 
common,  quality  of  lime,  128. 
cut-stonework,  dampness,  300. 
damp-resistance,  444. 
data  for  estimates,  193. 
drying  too  quickly  in  joints,  302. 
face-bricks,  338, 

face  joints  in  cut-stonework,  310. 
failure  of  buildings  from  lack  of  cohe- 
sion, 194. 
floor  arches,  tile,  468. 

foundations  below  and  above  grade,  97. 
frost,  action  of,  196. 
function  of,  in  brickwork,  335. 
gauged,  plaster  of  Paris  added  to  lime, 

197. 
grouting,  '192. 
heat  resistance,  444. 

heating   materials    in    freezing  weather, 
198. 


946 


INDEX. 

Mortar— Mortar  Colors. 


high  temperature,  interference,  with  nor- 
mal setting,  197. 
impervious  to  water,  196. 
joints  in  flat  stone  arches,  290. 
lime,  absorption  of  carbonic  acid  in  set- 
ting, 134. 
absorption  of  water,  196. 
addition  of  cement  in  rapid  work,  136. 

of  sugar  in  thick  walls,  197. 
additional  strength  by  sugar,  197. 
adhesion  to  bricks,  135. 
■allowable  stress  limited,  136, 
stress  on  brick  piers,  136. 
alternate  freezing  and  thawing,  198. 
application  of  full  load  before  harden- 
ing, 195- 
artificial  limestone,  134. 
attainment  of  strength,  136. 
brick  buildings,  335. 
,  bricks,  sand-lime,  329. 
brickwork,  freezing  weather,  339. 
cement  mixed,  335. 
chemical  changes  in  setting,  133. 
chemistry  of  setting,  according  to  Mr. 

C.  F.  Mitchell,  134. 
color,  130. 

complete  hardness,  133. 
drying- resisting  pressure,  134. 

too  quickly,  133. 
durability  of,  135. 

when  used  in  brickwork,  135. 
effect  of  freezing,  198. 

of  sand  on  hardening,  134. 
estimating  quantities  of  materials,  193. 
exclusion  of  air  while  setting,  133. 
freezing  before  setting,  133. 
frozen,  340. 

hardening,  furnishing  bond,  134. 

according  to  Mr.  Edwin  C.  Eckel,  134. 
heat-resistance,  444. 
in  damp  places,  133. 
increase  of  strength  by  plaster  of  Paris, 

.  ^97- 
limits  to  use,  136. 
making  of,  129. 

measuring  proportion  of  sand,  130. 
mixing  in  sand,  130. 
phenomena  of  setting,  133, 
processes  of  setting,  134. 
proportions  of  sand,  130,  135. 

for  brickwork,  130. 

for  stonework,  130. 
pure,  avoidance  of,  135. 

setting  of,  135. 
recarbonation,  134. 
reduction  of  water  in  setting,  134. 
rich,  130. 

safe  crushing  strength  of,  195. 
s6t   quickened   by   addition   of  sugar, 
197. 

setting    according    to    Prof.  Clifford 

Richardson,  134. 
setting,  133. 

forming  crystals  of  CaC03,  134. 
settlements  in  masonry,  303, 
specifications,  827. 

specimen   from   temple   on   Island  of 

Cyprus,  135. 
stiff,  130. 

strength  affected  by  alternate  freezing 

and  thawing,  133. 
strength  of,  135. 
tempered,  130. 
time  of  setting,  132. 
under  water,  132. 
use  in  fire-proof  buildings,  136. 
use  of  sand,  131. 

use   regulated  by  building  laws,  136. 


with  sugar,  solubility  in  water,  197. 
lime-and-cement,  827. 

cut-stonework,  300, 
lime  and  natural  cement  use  in  ordinary 
brickwork,  136. 

use  in  rubble  foundations,  136. 
lime  and  Portland  cement,  use  in  con- 
struction of  light  foundation,  136. 
loads  on,  safe,  907. 
machine-made,  780. 

mixture  for  piers  of  Manhattan  Life  Ins. 

Co.'s  Bldg.,  New  York,  78. 
non-absorbent,  196. 
normal  consistency,  182. 
partition  blocks,  tile,  550. 
plastering   (see  plastering), 
quality  affecting  strength  of  wall,  97. 
quick-setting,  191. 
salt,  addition  of,  198,  339. 

effect  on  freezing  point,  198. 

on  strength,  198. 
proportions  used  in  freezing  weather, 
198, 

sand  and  cement,  density  of,  132. 
effect  on  cement  and  lime,  131. 
proportions  of,   with  Portland  or  nat- 
ural cements,  159. 
sea  water,  effect  of,  603. 
stone  columns,  292. 
piers,  304. 

with  heavy  loads,  303. 
stonework,  specifications,  821. 
strength,   194,  200. 

adhesive   and   tensile,    wind  pressure, 
196. 

sugar,  mixed  with  mortar,  197. 

temperature,  effect  on,  197. 

terra-cotta,  architectural,  835. 

tests,  special,  153. 

tiling  for  fire-proofing,.  832. 

white,  use  of  marble  dust  in  place  of 

sand,  202, 
wetting  bricks,  importance  of,  195. 
white,  132. 

with   plaster   of  Paris,  196. 
working  "short,"  191. 
Mortars,  limes  and  cements,  127. 
Mortar  colors,  199, 
black,  201,  204. 

stone,  202. 
blue,  201,  204. 

stone,  203. 
brick  manufacture,  326. 
bright  red,  204. 

stone,  203. 
brown,  201,  204. 

stone,  203. 
buff,  201. 

stone,  203. 
cement  and  concrete  work,  204. 
color  in  bed  and  after  drying,  204. 
cost,  200. 

dark  blue  stone,  203. 
dry,  200. 

effect  of  sands,  199. 

effect   of   temperature   and   moisture  on 

paste  or  pulp  colors,  200. 
for  Portland  cements,  table,  202. 
Germantown  lampblack,  200. 
gray,  201,  204. 

stone,  203. 
green,  201,  203,  204. 

stone,  203. 
importance  of  uniform  mixing,  204. 
*  injurious  effects,  200. 
kinds  of,  200. 

linseed  oil  to  deepen  shade,  203. 
mineral  pigments,  200. 


INDEX. 

Mortar  Joints — Office-buildings. 


947 


mixing,  203. 

with  lime,  203. 
modified   by   natural   color   of  materials 

of  mortar,  199. 
object,  199. 
objections,  200. 
paste,  200. 
period  of  use,  199. 
principal  colors  used,  200. 
pointing,  302. 
proportions,  200. 
pulp,  200. 
purple  stone,  203. 
quantities,  201,  204. 
red,  201,  204. 

stone,  203. 

lead,  injurious  effect,  200, 
oxide  of  iron,  201. 
results   from   artificial   coloring  matters, 
199. 

slate  color,  203. 

use  of,  199. 

violet,  204. 
stone,  203. 

white  stone,  202. 

yellow,  201,  204. 
stone,  203. 

and  stains,  199. 
Mortar  joints   (see  joints,  mortar). 
Molded  arch-rings,  284. 
Moldings,  label,  284. 
Mud,  soils,  foundations  on,  9. 
Mueser,  William,  diamond  bar,  681,  682. 
Mullions, 

Stone,  298,  299. 

terra-cotta,  835. 
Multiplex  steel   plate,  concrete  floor  •  rein- 
forcement, 512,  513,  514,  515,  516. 
Municipal  regulations  (see  building  laws). 
Muriatic  acid,  cleaning  stonework,  302. 
Museums,  walls,  thickness  of,  910. 
Mushroom    system     (see    concrete,  rein- 
forced). 

N 

Nails,  use  of,  staking  out  buildings,  2. 
National    Association    of    Cement  Users, 

cement  bricks,  334. 
National  Association  of  Manufacturers  of 

Sand-lime  Products,  332. 
Natural  bed  of  stone,  99. 
National  Brickmakers'  Association,  sizes  of 

bricks,  327. 
National  Fire-proofing  Co.,  New  York,  fire- 
proof dwellings,  583,  585,  586. 
partitions.  "New  York,"  548. 
Natural  bed, 

ashlar  work,  309. 
stone  lintels,  306. 
Natural  cement  (see  cement,  natural). 
Natural    Portland   cements    (see  cements, 

Portland). 
Nature  of  soils,  3. 

foundations,  3. 
Needling,  118,  120. 
placing  needles,  121. 
proportioning  size  of  beams,  120. 
removal  of  needles,  121. 
support  of  needles,  121. 
Needling    and    underpinning,    example  of 

heavy,  123. 
Neutral  axis  of  a  beam,  651. 
Neutral  surface  of  a  beam,  646,  6<,i 
New  Mexico,  bedding  of  pavement  stones, 
116. 

New  Orleans,  loads  on  piles,  35. 
New  process  lime,  hydrated  lime,  131. 


New  York, 

Akron,  hydraulic  cement  analysis,  145. 
Buffalo,  hydraulic  cement  analysis,  145. 
Fort  Wadsworth,  mortar  colors,  203. 
Madison  Co.,  natural  cements,  141. 
Rosendale,  hydraulic  cement  analysis,  145. 
New  York  City, 

American  Surety  bldg.,  caisson  founda- 
tions, 79. 
building  laws,  33. 

concrete  footings,  88. 
designing  foundations,  16. 
foundation  soils,  11. 
requirements  for  lime  mortar,  130. 
for  projections  of  brick  footings,  93. 
Cathedral  of  St.  John  the  Divine,  use  of 

silica-cement  in  foundations,  170. 
concrete  capping  for  wooden  piles,  37. 
Department  of  Bridges,  fineness  of  Port- 
land cements,  175. 
depth  of  bed  rock,  site  of  Singer  bldg.,  79. 

site  of  U.  S.  Exp.  Co.'s  bldg.,  80. 
failure    of    building   from    lack    of  ad- 
hesion of  mortar,  195. 
grouting,  192. 

Herald  building,  water-proofing  of  base- 
ment, III. 

Manhattan  Life  Ins.  Co.'s  bldg.,  caissons, 
75. 

Metropolitan  Life  Ins.    Co.'s  bldg.,  steel 

beams  grillage  on  rock,  60. 
Rapid  Transit  Subway,  specifications  for 
natural  cements,  154,  844. 
specification  for  Portland  cement,  177, 
848. 

Singer  building,  caissons,  79. 
subway,    fineness   of   Portland  cements, 
175. 

strength  of  natural  cements,  153. 
United  States  Express  Co's.  bldg.,  cais- 
sons, 79. 
construction,  80. 
New   York   Fire-proof   Column   Co.,  Ho- 
boken,  N.  J.,  columns,  concrete,  rein- 
forced, T.  I.  M.  patent,  701. 
New  York  State, 

natural  cements,  142. 
quality  of  natural  cements,  142. 
Rosendale  cement,  142. 
New  York  State  Canals, 

fineness  of  Portland  cements,  175. 
specifications  for  natural  cement,  844. 

for  Portland  cements,  848. 
strength  of  natural  cements,  153. 
New  York  tile  reinforced  floor  arch,  489, 
490,  491. 

"New  York  Times"  building,  construction 

of   column   footing,    foundations,  6. 
Newels,  iron  stone  stairs,  294. 
Nogging,  brick,  398. 

Non-absorbent  surfaces,  bricks,  glazed  and 

enamelled,  322. 
Non-fire-proof  buildings,  heights  and  areas, 

438. 

North  Dakota,  natural  cements,  143. 
Northwestern    Terra    Cotta    Co.,  Chicago, 

111.,  terra-cotta  details,  417. 
Nosings,  stone  steps,  293. 
Nova  Scotia  gypsum,  788. 


Oflfice-buildings, 

drawings  for  cut-stone,  295. 
partitions,  549. 

proportioning  the  footings,  16. 
roofs,  brick  paving,  322. 
walls,  thickness  of,  910, 


948 


INDEX. 


Official  Survey. — Petrographic  Miscroscope. 


Official  survey,  staking  out  city  buildings,  3. 

Offsets  for  footing  courses,  safe,  table,  90. 

Ohio,  natural  cements,  143. 

Oiling  stonework,  259. 

Old  cut-stonework,  cleaning,  302. 

One-piece   concrete   blocks   with  staggered 

voids  (see  concrete  blocks). 
Onyx  marbles,  chemical  composition,  235. 

886. 

Oolitic  limestones,  227. 
Openings, 

brick  or  stone  walls,  278. 

brick  walls,  280,  359. 

hollow  walls,  372. 

stone    walls,     arrangement    of  stones 
under,  100. 
Ordinances,  building  (see  building  laws). 
Ornament,   surface,   brick,  341,   346,  347, 
^     348,  349. 
Ornamental, 

brickwork  (see  brickwork,  ornamental). 

terra-cotta  (see  terra-cotta). 

work,  stone,  protecting,  301. 
Outhouses,  specifications,  830. 
Owner,    incurring    expense    for  borings, 

foundations,  4. 
Oxide  of  iron,  brick  manufacture,  312. 

P 

Paint, 

fire-proof,  447. 

hydraulic  plaster  stains,  469. 
mineral,  brick  manufacture,  326. 
Painting, 
bricks,  317. 

ironwork  in  foundations,  96. 

steel  beams  in  concrete,  59. 

stonework,  259. 
Pallet  system,  brick  manufacture,  314. 
Panels, 

brick,  341,  346,  347. 

terra-cotta  and  stone  construction  com- 
pared, 419. 
Papier-mache  false  girders,  575,  577. 
Paragon  wall  plaster,  787,  789. 
Parapet  walls,  brick,  344. 
Pargetting,  385. 

Parker,    Joseph,    introduction    of  Roman 

cement,  141. 
Partition  blocks, 

plaster,  weight,  543. 

reinforced,  544. 

scaglioline,  543. 

tile  circular  and  angular  corners,  550. 

Phoenix,  550. 

typical  shapes,  549. 

weights,  550. 
Partitions, 
brick,  542. 

thickness,  363. 
concrete,  542. 

block,  542,  746. 
conductivity,  541. 
corridors,  541,  549. 
Ellendt  reinforced  block,  545. 
ferroinclave,  517. 
fire-proof,  541. 

brick,  542. 

concrete,  542. 

metal-and-plaster,  550. 

tile,  548. 

types  of,  542, 
gypsinite,  545. 
gypsite,  545. 

heat-resistance,  541,  543. 
mackolite  partition  tile,  545. 
metal-and-plaster,  550. 


allunited  steel  studding,  556. 

Berger,  555. 

cost,  556. 

double,  552. 

ferroinclave,  559. 

kinds  of  metal  lath  for,  559. 

Kiihne's  metal  lath,  558. 

heat-resistance,  550. 

rib-studs,  556. 

single  solid,  552. 

triangular  mesh  steel  fabrics,  558. 

truss  metal  lath,  558. 

water- resistance,  550. 

weights,  552,  556. 

without  studding,  558. 
metal  lath  and  plaster,  door  and  window 

frames,  804,  805. 
office-buildings,  549. 
openings  in,  541. 
plaster-block,  543. 
rigidity,  541. 

solid  metal  lath  and  studding,  842. 
Sackett's  wall-board,  547. 
sound-resistance,  541. 
stairways,  549. 
strength,  541. 
tile,  548. 

frames  for  doors,  548. 

"New  York"  reinforced,  548. 

plastering,  548. 

reinforced,  550. 

specifications,  833. 

whitewashing,  548. 
"U.  S.  G."  fibered  plaster  blocks,  545. 
wall-board,  543,  547. 
water-resistance,  541. 
weight,  541. 
Party-lines,  staking  out  buildings,  3. 
Party-walls,  83. 
brick,  363. 

brick  walls  and  concrete  columns,  620, 
621. 

Patent-hammer  for  stone  dressing,  271. 
Patent-hammered  work,  274, 
Patent  plaster  (see  plaster,  patent). 
Patterns, 

brick,  341,  346,  347,  348,  349. 
stone  arches,  283. 
surface,  345. 
Pavements  (see  also  sidewalks), 
brick  paving,  323. 

specifications,  830. 
cement,  86  r. 
driveways,  322. 
materials,  115. 
roofs,  322. 
stone,  115. 
Pavement  vaults,  construction  of,  114. 
Paving  bricks  (see  bricks,  paving). 
Payments,  extra,  for  masonry  for  too  deep 

trenches,  24. 
Pean-hammer  for  stone  dressing,  269,  274. 
Penetration  shoe,  simplex  concrete  piles,  43. 
Pediments,  terra-cotta,  425,  426. 
Pelton's    system    of    released    wall  facing 

(see  wall  facing). 
Pelton,  John  Cotter,  California,  wall  fac- 
ing, released,  590. 
Penstocks,  concrete,  595. 
Pent-houses,   specifications,  834. 
Perforated  sheet-metal  lath  (see  lath,  per- 
forated sheet-metal). 
Permits   for   buildings   erected  in  United 

States  in  1906,  901. 
Perth    Amboy,    N.    J.,    tests    for  bearing 

power  of  piles,  34. 
Petro'^ranhic    microscope,    tests    on  lime- 
silicates,  330. 


INDEX. 


949 


Philadelphia,  Pa. — Plaster. 


Philadelphia,  Pa., 

Bureau  of  Bldg.  Inspection,  33. 

natural  cements,  specifications,  154. 

piles  of  South  street  bridge  approach,  35. 

Portland  cements,  specifications,  177. 
Phoenix  partition  blocks,  550. 
Phoenix  wall  construction,  449. 
Phoenix  wall  tiles,  586. 
Picked  work,  271,  274. 
•  Picture-moldings, 

grounds  for,  on  metal  and  plaster  parti- 
tions, 557,  558. 

tile,  molded  hollow,  578. 
Piers, 

brick,   allowable  stress  on  lime  mortar, 
,  136. 

bond-stones,  294. 
buckling  of,  295; 
cracks  in,  295. 
loads  on,  safe,  907. 

proportions    of    cement    and    sand  in 
mortar,  190. 

salmon,  324. 

stability  of,  335. 

strength,  402,  906. 
'    warped,  324. 
brickwork  for,  311. 
concrete  blocks,  864. 
excavations  for,  in  heavy  buildings,  24. 
heavily   loaded,   use   of  cement  mortar, 
188. 

isolated,  as  a  foundation  on  soft  soils,  14. 
Portland  cements,  use  of,  170. 
separate,  to  prevent  cracks,  21. 
stone,  dressing  of,  272. 

factor  of  safety,  303. 

height  of,  304. 

mortar  for,  304. 

random-coursed-ashlar,  266. 

safe  loads,  304. 

specifications,  820, 

strength  of,  303. 
terra-cotta,  architectural,  416,  417. 
wall,  bond  stones  in,  295. 
Pilasters, 

belt-courses  and  washes,  277. 
brick,  341. 
false,  456. 
Piles, 

blunt,  27. 
classes  of,  25, 

concrete  (see  concrete  piles), 
footings,  made  land,  9. 
driving  stratum  of  hard  material,  29. 
wood,  actual  loads  on,  35. 

arrangement  of  capping  stones,  36. 

bearing  power,  30. 
examples  of,  31. 
overestimated,  35. 

bearing  value  determined  by  testing,  34. 

booming  of,  28. 

capping,  36. 

concrete  filling  between,  38. 
concrete  capping,  37. 

with  imbedded  rods,  38. 
cost  of,  39. 
cutting  off,  36. 

decay  above  low  water  mark,  36. 
driving  to  hard  stratum,  29. 

diminishing    resisting   properties  of 
soil,  26. 

usual  method,  28. 

with  drop-hammer  and  water-jet  in 
conjunction,  30, 

with  water-jet,  30. 
effect  of  broomed  head,  36. 
experiments  on  bearing  power,  34. 


formula  for  safe  working  load,  32. 

granite  capping,  36. 

grillage  capping,  38. 

long,  acting  as  columns,  26. 

materials  and  qualities,  27. 

municipal  regulations,  33. 

not  pointed,  27. 

penetration  affecting  bearing  value,  31. 
pointing,  27. 
preparation,  27. 

proportioning  number  of,  26,  36. 
protection  of,  28. 

refusing  to  sink  to  average  depth,  29. 

removal  of  bark,  27. 

ringing  top  of,  28. 

rot  prevented  by  concrete,  37. 

safe  bearing  value  of,  table,  31, 

shod  for  compact  soils,  28. 

short,  depending  on  friction,  26. 

to  consolidate  soil,  26. 
spacing  of,  36. 

when  water  jet  is  used,  36. 
wood,  specifications,  817. 
steel  beam  grillage  capping,  expense, 
39. 

sustaining   power    according    to  Gen. 

Wm.  Sooy  Smith,  34. 
Able  for  safe  load  on,  32. 
testing  bearing  power  of,  29. 
tests  for  bearing  power  at  Buffalo,  N. 

Y.,  34. 

at  Perth  Amboy,  N.  Y.,  34. 
at  Philadelphia,  35. 
in   erection    of   Chicago   Public  Li- 
brary, 34, 
use  of,  26. 

wedging  under  cap,  36. 
woods  used,  27. 
Pile  foundations, 

affecting  adjoining  buildings,  25. 
cheapness,  25. 
objections  to,  25. 
reliability,  25. 
saturated  soil,  25. 
settlement  of  structures  on,  26. 
unequal  settlement,  27. 
Pin-connected  girder  frame  (see  concrete, 

reinforced). 
Pins,    iron,   fixing  lot   lines,   staking  out 

buildings,  3. 
Pioneer     Company,     Chicago,     111.,  floor 

arches,  tile,  481. 
Pipe,  Pipes, 

coverings,  fire-proofing,  450. 
floors,  fire-proof,  laying  over,  470. 
furring  for,  573,  575. 
gas,  470. 

holes  in  walls  for,  109. 

next  to  columns,  fire-proofing,  460. 

sewer,  production,  value  of,  903,  905. 

sleeves,    concrete,    reinforced,  specifica- 
tions, 856. 

spaces,  ceilings,  suspended,  539. 

water,  470. 
Pitch  of  stone  steps,  293. 
Pitch  and  asphalt  roofing,  539. 
Pitch-faced  stonework,  271. 
Pitched  roofs  (see  roofs). 
Pitching  chisel,  271. 
Pitching  off, 

stone  faces,  271. 

trimmings,  267. 
Pits,  clay,  brick  making,  314. 
Pitted  bricks,  313. 
Plaster, 

asbestic,  fire-resistance,  444. 

chemical,  787. 

fibered,  partition  blocks,  543. 


950 


INDEX. 

Plaster-block — Q,uoins. 


fibrous,  796. 

fire-proofing,  columns,  449. 
fire-resistance,  444. 
hard  wall,  786,  787- 

advantages  in  using,  791. 
fire-resistance,  444. 
how  sold,  789. 
putting  on,  790. 
sand  finish,  839. 
lime,  fire-resistance,  444. 
machine-made,  780. 
natural  cement,  786. 
patent,  786,  787- 
proportions  of  materials,  781. 
putting  on,  783. 
stains,  hydraulic  paints,  469. 
^        smoke  of  hoisting  engines,  469. 
Plaster-block,  374. 

fire-proofing,  columns,  459. 
Plaster-block  partitions  (see  partitions). 
Plaster-board,  374,  775. 
Plaster-board  partitions,  547. 
Plaster  of  Paris, 
fire-resistance,  445. 
in  mortar,  196. 

Lafarge  cement,  301. 
non-hydraulic  cement,  139. 
partition  plaster-blocks,  543.  ^ 
pointing  putty,  302. 
scaglioline,  543. 
Plaster  cornices  (see  cornices). 
Plastered  ceilings,  efilorescence,  469. 
Plastering, 

back  of  retaining-walls,  104. 
backing,  299. 

back-plastering,  specifications,  837. 

brick  walls,  outside,  827. 

brickwork,  mortar  joints,  337. 

cement,  proportions  of  cement  and  sand 

in  mortar,  190. 
ceilings  on  tile  floor  arches,  470. 
cost  of,  806. 
exterior,  797. 
interior,  776. 

hard  wall,  specifications,  838. 
lime,  quality,  128. 
measuring,  805. 
mixing  mortar  for,  779. 
mortar  for  water-proofing  or  stucco-work, 
proportions  of  cement  and  sand,  190. 

impervious  to  water,  196. 
steel  beam  footings,  59. 
partitions,  tile,  548. 
plaster-boards,  547. 
quantities  of  materials,  806. 
sand  finish,  837. 

colored,  809. 
specifications,  837. 

wall  covering  over  damp-proofing  mate- 
rial, 110. 
Plastic  clay  fire-brick,  324. 
Plinths,  rustic,  in  ashlar,  265. 
Plunger  machines,  brick  manufacture,  315. 
Plugging  stone  backing  for  plastering,  299. 
Plugs, 

wall,  metal.  Rutty,  365,  374. 

wood,  brick  walls,  364. 
Plumb  bond    (see  bond,  plumb). 
Pointed  arches,  287. 
Porosity,  slate,  884,  897. 
Patching,  cut-stonework,  308. 
Perch  of  stone,  307. 

Point  tool  for  dressing  stones,  271,  272,  274. 
Pointed  work  on  stone  dressing,  272. 
Pointing, 

brickwork,  830. 

cut-stonework,  300,  301,  310. 

face  brickwork,  338. 


mortar,  durability  and  imperviousness  to 

water,  196. 
Portland  cements,  170. 
stonework,  824. 
terra-cotta,  architectural,  421. 
Polishing  stones,  273. 
Polychrome  terra-cotta,  407,  408. 
Porches,  stone,  292. 
Porosity, 
bricks,  311. 

paving,  323. 
fire-bricks,  324. 
Porous  tiling  (see  tiling,  porous). 
Portland  cements  (see  cements,  Portland). 
Portland  cement  mortar   (see  mortar,  ce- 
ment, Portland). 
Portland    Stone,    England,    from  which 

Portland  cement  is  named,  163. 
Post-auger,    boring   to    test   character  of 
soil,  4. 

Posts,  fence,  concrete,  595. 

Potsdam,  N.  Y.,  sandstone  columns,  305. 

Pottery, 

kilns  for,  319. 

production,  value  of,  903,  905. 
Power-houses,  walls,  thickness  of,  910.  ^ 
Pressed  bricks  (see  bricks). 
Pressing-chamber,  brick  manufacture,  315. 
Pressing  machines,  brick  manufacture,  316, 

317. 
Pressure, 

center  of,  important  calculations,  20. 

on  clay  soils,  7. 

on  footings,  clay  soils,  7. 

proportionate  on  footing  courses,  91. 

walls  on  clay  soils,  7. 
Priddle,  Arthur,  San  Francisco,  Cal.,  Prid- 

dle  reinforcing  bar,  682,  683. 
Prong  lock  wireless  steel  furring,  571,  575. 
Property  lines,  staking  out  city  buildings,  3. 
Proportioning  the  footings,  to  the  weight 

suppoi'ted,  14. 
Protection, 

brickwork,  340. 
specifications,  825. 

concrete,  reinforced,  722. 

cut-stonework,  301. 

reinforcements  in  concrete,  725. 

stonework  during  erection,  259. 

terra-cotta,  architectural,  836. 
Public  buildings  (see  buildings,  public). 
Puddlers,  concrete  work,  630,  631. 
Pumps,  draining  trench  water  with,  24. 
Pug-mill,  brick  manufacturer,  314,  315. 
Puritan  flooring,  534. 
Putty,  pointing,  302. 

Puzzolan  cements  (see  cements,  puzzolan). 


Quarrying, 

limestone,  264. 

sandstone,  264. 
Quarry-water  in  stones,  259. 
Quicklime  (see  also  lime,  common). 

bricks,  312. 
Quicksand, 

preparation  for  footings,  70. 

safe  bearing  strength  of.  Table  10. 
Quoins, 

brick,  267. 

draft-lines,  271. 

drawings  for,  in  ashlar,  296. 

rubble  walls,  264. 

rustic,  in  ashlar,  265. 

stone,  size  of,  266. 

stone  Vermiculated  work,  274. 

and  jambs,  266. 


INDEX. 

Radial  Block  Brick  Chimneys — Retaining:->valls. 


R 

Radial  block  brick  chimneys,  387. 

Radial  blocks,  chimney  constiuction,  325. 

Radial  bricks  (see  bricks). 

Raking  out  joints,  338. 

Railings,  iron,  stone  stairs,  294. 

Railroad  rails, 

imbedded  in  concrete  to  prevent  grillage 
beams  breaking  through,  60. 

number  of  layers  in  spread  footings,  59. 

use  in  spread  footings,  59. 
Raised  joints,  stonework,  302. 
Raised  mortar  joints,  263. 
Raking  out  mortar  joints,  310. 
Rammers,  concrete  work,  598,  630,  631. 
Ramming,  trench  bottoms,  24. 
Random-coursed-ashlar,  266. 

piers,  266. 
Random  rubblework,  264. 
Ransome  &  Smith  Co.,   Ransome  twisted 

bar,  682. 
Ransome  artificial  stone,  260. 
Ransome  bar  (see  concrete,  reinforced). 
Ransome  concrete  floors,  636,  637,  641. 
Ransome    Concrete    Machinery    Co.,  New 
York,  Ransome  twisted  bar,  683,  684. 
Ransome's  process  of  waterproofing  stone- 
work, 260. 

Rapp  concrete  and  brick  floor  arch  system 

(see  floors,  fire-proof). 
Rapp  Fire-proofing  Co.,  column  fire-proof- 

ing,  456,  457. 
Rapp  system  of  floor  arches,  467. 
Rattler,  testing  toughness  of  paving  bricks, 

323. 

Raymond  concrete  piles,  42. 
Red  bricks  (see  bricks,  red). 
Regular-coursed-ashlar,  265. 
Regulations, 

building  (see  building  laws). 

Concrete  building  blocks,  862. 

municipal,  regarding  wooden  piles,  33. 
Reid,  Homer  A., 

fineness  of  cements,  152. 

grouting,  193. 

mixture  of  Portland  and  natural  cements, 
148. 

mortar  colors,  202. 

Portland  cements  used  in  reinforced  con- 
crete construction,  170. 
process    of    manufacture    of  Portland 

cements,  168. 
specific  gravity  of  Portland  cements,  173. 
tensile  strength  of  cements,  186. 
Reinforced   concrete    (see   concrete,  rein- 
forced). 

Reinforced  tile  floor  arch  construction  (see 
tile,  reinforced). 

Reinforcements  (see  also  concrete,  rein- 
forced). 

adhesion  of  cements  to  iron,  187. 

steel,  187. 

in  concrete,  665. 
average  usual  disposition,  diagrams,  661. 
bars,  ribbed,  506. 

beams,  concrete  reinforced,  percentage  of 
reinforcement,  652. 

Berger  corrugated  steel  plate,  for  con- 
crete floors,  515. 

columns,  concrete,  Golding  bar,  701. 
hooped,  672,  673. 

hooped  and  longitudinal  reinforce- 
ments compared,  672. 

Kahn  trussed  bars.  699. 

longitudinal,  668,  671. 

T.  I.  M.  patent  reinforcement,  701, 
702. 

vertical  reinforcementt,  699. 


wrapped,  672,  673. 
concrete  beams,  amount  and  disposition 
of,  662. 

effective  arrangements,  649. 
concrete  construction,  677. 

adhesive  resistance,  715. 
concrete,   deformed  bars   and   rods,  51, 
680. 

mechanical  bond,  680. 
percentage  of  reinforcement,  663. 
plain  bars  and  rods,  680. 
square  twisted  bars,  56. 
specifications,  852. 

stirrups,  686,  687,  688,  689,  691,  692, 
693,  694,  699,  704,  705,  706,  707, 
708,  709,  711,  712,  713,  716. 
stool-lock  bar  spacers,  688. 
concrete   floors,   position   and  direction, 
500. 

rods  and  bars  versus  wire  fabrics,  499. 

concrete  girders,  unit  sockets  for  sup- 
porting girder  frames,  692,  694. 

deformed  bars,  strength,  adhesive,  666. 

different  forms,  for  concrete,  499, 

example  of  effect  in  increasing  strength 
in  a  beam,  647. 

expanded-metal,  concrete  floors,  520. 

ferroinclave  steel  sheets,  515,  516,  517, 
520. 

Johnson  bar,  pulling-out  tests,  666. 
lock-woven  fabric,  concrete  floors,  522. 
methods  of,  in  concrete,  499. 
monolith  steel  bar,  Golding,  684,  685. 
object  of,  647. 

placing  in  the  concrete,  specifications,  853. 

rods  in  concrete  footings,  56.  ^ 
pulling-out  tests,  666. 
Ransome  bar,  pulling-out  tests,  666. 
simplest   form,   in   concrete   beam,  647, 
648. 

spacing  of  rods,  52. 

steel,  amount  in  concrete  footings,  for- 
mula, S3, 
fabric,  508. 

in  concrete  work,  677. 
wire,  concrete  floors,  522. 

Thatcher  bar,  pulling-out  tests,  666. 

truss  metal  lath,  558. 

types  of,  in  concrete  work,  679. 

welded  metal  fabric,  concrete  floors,  523. 

wire,  in  concrete  blocks,  742,  743. 
truss,  for  tile  floor  arches,  489. 
Reinforced 

partition  blocks,  544. 

tile  partitions,  550. 
Reliance  steel  furring  (see  furring). 
Relieving-arches,  277. 

brickwork,  360,  372,  382. 

specifications,  827. 
Relieving-beams, 

open  joints  under,  285. 

steel,  stone  arches,  285,  286. 
lintels,  277. 
Renaissance  architecture, 

arches  in,  283, 

label-molds,  284. 
Repressed  bricks  (see  bricks,  repressed). 
Reservoirs,  concrete,  595. 
Reservoir  walls,  concrete,  reinforced,  635. 
Resisting  moment,  645. 
Resisting  shear,  645. 
Responsibility  of 

contractors,  staking  out  buildings,  2. 

superintendent,  staking  out  buildings,  2. 
Restrained  beams,  645. 
Retaining-walls,  96,  595- 

batter  of  outer  face,  104. 


952 


INDEX. 

Rex  flooring^ — Rustic. 


computations  for  thickness  and  -cross-sec- 
tion, 102. 

concrete,  595. 

reinforced,  104,  635. 
shrinkage  rods,  105. 
stability,  104. 
thickness  of,  104. 

design  and  construction,  103. 

different  from  foundation  walls,  loi. 

empirical  rules,  102. 

exposed  faces  of  concrete,  treatment  of, 

10$. 

failure  by  bulging,  102. 

overloading,  103, 

overturning,  102. 

sliding  of  footings,  102.  ^ 

vibrations,  103. 
footings  below  frost  line,  104. 
formulas,  theoretical,  102. 
general  description,  loi. 
gutters,  104. 
inclined  faces.  103,  104. 
manner  of  failure,  102. 
materials,  103. 

mixture  for  reinforced  concrete,  105. 
mortar,  103. 

new   footings   extended   below   those  on 

adjoining  property,  86, 
plastering  brick,  104. 
resistance  of  earth  pressure,  loi. 
stability  depending  on  filling,  104. 
stepping  on  back,  104. 
use,  1 01. 
Rex  flooring,  ■  534. 

Ribbed  bars,   reinforcements  for  concrete 

floors,  506. 
Rib-lath,  556. 

Rib-lath  studs  (see  also  studs,  rib-lath). 
Rib-lath  triangular  expanded-metal  furring 

studs,  571,  573. 
Rib  sheet-metal  lath,  568. 
Richardson,  H.  H.,  arches,  284. 
Richardson,  Prof.  Clifford,  setting  of  lime 

mortar,  134. 
Richey,  H.  G., 

estimating  quantities  of  materials  in  lime 

mortars,  193. 
Portland  cement  barrels,  weights,  meas- 
urements and  contents,  179. 
weights  of  mortar  colors,  204. 
what  a  barrel  of  Portland  cement  will 
do,  194. 
Rigidity,  partitions,  541. 
Ring-course,  stone  arches,  281. 
Roads,  concrete,  594. 

Roadway  pavements,  concrete  foundations 

_     for,  595. 

Rock, 

building  on,  foundations,  5,  6. 
classification,  212. 

column  footing,  "New  York  Times" 
building,  foundations,  6. 

cut  to  level  planes,  foundations,  5. 

draining  surface  water  from,  founda- 
tions, 5. 

excavation,  use  of  concrete,  founda- 
tions, 5. 

fissures,  deep,  spanned  by  arches  of  brick 
or  stone,  6. 
filled  in,  "New  York  Times"  building, 
foundations,  6. 
footings,  method  used  to  secure  firm,  5. 
for  foundation  bed,  foundations,  5. 
foundations,  4. 

different  levels,  6. 

lower  levels  laid  in  cement  mortar,  6. 
geological  record,  214. 
granite,  safe  bearing  strength  of,  10. 


strength,  safe  bearing,  10. 

trap,  248. 
Rock-faced 

arches,  282. . 

ashlar,  cost  of,  271. 

stonework,  271. 
broken  ashlar,  265. 
Rods, 

reinforcing  (see  reinforcing  rods). 

versus  wire  fabrics  as  reinforcements  for 
concrete  floors,  499. 
Roebling  concrete  floor  arch  system  (see 

floors,  fire-proof). 
Roebling    Construction    Co.,    column  fire- 
proofing,  456. 
Roebling  wire  lath,  562,  563. 
Roman  bricks  (see  bricks,  Roman). 

tiles,  (see  tiles,  Roman). 
Romanesque     architecture,     stone  arches, 

stilted,  283. 
Romans,  early  use  of  cements,  141. 
Roof-coverings,  fire-proof  roofs,  536. 
Roofing, 

asphalt,  536. 

copper,  536. 

felt,  539. 

gravel,  536,  539. 

heat-resistance,  536. 

pitch  and  asphalt,  539. 

slate,  244,  536. 

tar,  536. 

tin,  536. 

tiles,  clay,  536. 
metal,  536. 

wood  shingles,  244. 
Roof  surfaces,  fire-proof,  specifications,  834. 
Roofs, 

brick  paved,  322. 

fire-proof,  534. 

fire-proofing,  specifications,  832. 

flat,  fire-proofing,  535. 

heat-resistance,  535. 

mansard,  fire-proofing,  535. 

pitched  cornices  of  brick  for,  344. 
fire-proofing,  535. 

trussed,  fire-proofing,  535. 
Rosendale  cement  (see  cement,  natural). 
Rough-cast  exterior  plastering,  797. 
Rough-pointed  stone  dressing,  272. 
Rowlocks,  arches,  94. 
Royal  wall  plaster,  786,  787,  788,  789. 
Rubbed  sandstone  ashlar,  273 

work  in  stone  dressing,  273. 
Rubbing-beds  for  stone  dressing,  273. 
Rubbing  stone  trimmings,  267. 
Rubbish,   specifications,  830, 
Rubble 

backing,  300. 

concrete  (see  concrete,  rubble), 
stone,  cost  of,  306. 

measurement,  units  of,  306,  307. 

arches,  289. 
stonework,  263. 

cost    of,    31  T. 

random,  264. 
specifying,  264. 
suburban  architecture,  264, 
tools  for  dressing,  269, 
walls  (see  walls,  rubble). 

Ruled  work,  brickwork,  338. 

Rupture,   modulus    (see   modulus    of  rup- 
ture). 

Rust,  anchors,  300. 

Rusticated  joints  (see  joints,  rusticated). 
Rustic 

buildings,  264. 

plinths,  265. 

quoins,  265, 


INDEX. 

Rusticated  Stonework — Setting. 


953 


Rusticated  stonework,  274. 
Rutland,  Vt.,  maiDie  coiumns,  305. 
Rutty  wall-plugs,  365,  374. 


Sackett  Wall  Board  Co.,  New  York,  547. 

Safe  strength  (see  strength,  safe). 

Safe  load  tor  wooden  piles,  tables,  32. 

Safety  treads,  stairs,  860. 

Salem    Laundry    building,    Salem,  Mass., 

concrete,  reinforced,  698. 
Salmon  bricks  (see  bricks,  salmon). 
Salt,  in  mortar,   198,  339,  340. 
Salt  water,  concretes,  eriect  on,  603. 
Samples,  concrete  blocks,  864,  865,  866. 
Sand, 
bank,  131. 

beach,  used  as  filling,  made  land,  foun- 
dations, 9. 
brick  manufacture,  311,  312. 
bricks,  sand-lime,  329. 
cement  bricks,  334. 

color,  as  affecting  concrete  blocks,  744. 
concrete  blocks,  730,  731. 

reinforced,   specifications,  856. 
coarseness,  132. 

coarse   with  cement,   density  of  mortar, 
132. 

comparison  of  different  kinds,  132. 

dry,  specific  gravity,  132. 

effect  on  hardening  of  lime  mortar,  134. 

fine  and  coarse  mixed,  weight  of,  132. 

for  pressed  brickwork,  132. 

for  rough  stonework,  132. 

foundations,  4. 

foundation  beds,  9.. 

grains,  sharp,  132. 

inspection  of,  132. 

loam  or  clay  in,  132. 

mortar,  cement,  weakening  effects,  131. 

plastering,  778. 

use  in,  131. 
pit.  131.- 

proportion  in  cement  mortars,  181. 

in  cement  mortar  for  work  under  wa- 
ter, 189. 

in  lime  mortar,  135. 

Portland  or  natural  cement  mortars, 
.159. 

reduction  -  of   tendencies   to   shrink  and 

crack  in  mortars,  189. 
safe  bearing  strength  of,  table  10. 
screening,  132. 
sea,  objections  to,  131. 

specifications,  usual  requirements  of,  131. 
tests,  conclusions,  131. 

for  cleanliness,  132. 

for  loam  or  clay,  132. 
voids,  132. 

weights,  depending  upon  moisture,  131. 
of  dry  and  moist,  132. 

where  obtained,  131. 

with  clay,  foundations,  8. 
Sand-blast, 

bricks,   sand-lime,  332. 

cleaning  stonework,  302. 
Sand-finish, 

hard  wall  plaster,  839. 

plastering,  837. 
colored,  809. 
Sand-lime  stones,  261. 
Sand  holes,  sandstones.  308. 
Sand-lime  bricks  (see  bricks,  sand-lime). 
Sandstone, 

absorption,  ratio  of,  881,  891. 

chemical  composition,  884. 

cleaning,  302. 

color,  308. 


coursed-ashlar,  264. 

defects  in,  308. 

description  of  important,  238. 

dressing,  27^,  271. 

finish,  272,  273. 

fire-proof  construction,  440. 

general  description,  236. 

heat-resistance,  891. 

modulus  of  rupture,  305. 

production,  238. 

during  1896-1906,  205,  206. 

in  1905  and  1906,  value  of,  878.  870. 
sand  holes,  308. 
specifications,  822. 
strength,  crushing,  882,  883. 

safe  bearing,  10. 
weathering,  253. 
weight,  882,  883,  891. 
Sandstone,  Fond  du  Lac,  Wis.,  columns. 

305. 

Sandstone,   Longmeadow,   Mass.,  columns 
305. 

Sandstone,  Manitou,  Colo.,  columns,  305. 
bandstone,  Ohio,  columns,  305. 

Potsdam,  N.  Y.,  columns,  305. 
bandstone  ashlar  (see  ashlar,  sandstone), 
bandstone  buildings,  lists  of,  888,  880,  800 
band-struck  bricks,  313. 
Sand-trap,  for  draining  areas,  112. 
San  Francisco,  cement  sidewalks,  114. 
banitary  bases  or  wall-floor  angles,  534. 
banitas  flooring,  534. 

San    Stafano,    Bologna,    Italy,    cornice  of 

Baptistry,  345. 
Sap  in  granite,  308. 
Sash, 

fire-proof,  541. 

metal,  582. 
Saw^marks,  use  of,  staking  out  buildings, 

Sawed  stone  (see  stone,  sawed). 
Sawdust, 

brick  manufacture,  313. 

flooring,  534. 
Sawing  sandstone  ashlar,  273. 
Saylor,    David   A.,    founder    of  Portland 

cement,    industry   in   America,  164. 
Scagliola,  795. 

Scaglioline,  partition  blocks,  543. 
School-houses, 

computing  weight  on  footings,  16. 

walls,  thickness  of,  908. 
Scotch-hone,  plaster  finishing,  796. 
Scott's  cement  (see  limes,  selenetic). 
Scratch  coat,  plastering,  783. 
Seams,  granites,  308. 
Seasoning  stones  for  building,  258. 
Sea-walls,  concrete,  610. 
Sea  v/ater,  concretes,  effect  on,  603. 
Section  modulus,  for  rolled  steel  I-beams, 
table,  63. 

Sectional  concrete  floor  construction  (see 

floors,  fire-proof). 
Segmental  arches,  285,  288. 
concrete    floor   arches    (see   floors,  fire- 
proof). 

tile    floor-arches,    472    (see    also,  floors, 
fire-proof). 
Semi-circular  arches,  283. 
Semi-porous  tiling   (see  tiling). 
Set,  cement,  Portland,  in  reinforced  work, 

849. 
Setting. 

concrete,  602. 
cut-stonework,  300,  823. 

specifications,  829. 
ironwork,  829. 

mortars,  change  of  volume,  199. 


954 


INDEX. 


Settlements — Skew-backs. 


steelwork,  829. 
stone  sills,  280,  301. 
terra-cotta,  specifications,  830. 

architectural,  421. 
tile  floor-arches,  segmental,  467. 
Settlements, 

adjoining  walls,  303. 

arches,  281. 

brick  backing,  299. 

caused    by    driving    piles    on  adjoining 

site,  25. 
cut-stonework,  298. 
footings,  imperfect,  93. 
foundations,  303. 

foundations,   partly  on   rock,   partly  on 

soil,  6. 
joints,  brick  arches,  285. 

masonry,  278. 

of  walls,  100. 
porches,  stone,  292. 
sills,  breaking,  100. 

stone,  280,  301. 
structures  on  piles,  26. 
taken  up  by  jackscrews,  123. 
tracery,  stone,  299. 

unequal,  different  levels,  foundations,  6. 
causes,  foundations,  1 5. 
pile  foundations,  27. 
uniform,  compressible  soils,  48. 
Sewers, 

concrete,  594,  595. 
concrete,  reinforced,  635. 
Shafts, 

elevator,  brick  facing,  glazed  and  enam- 
elled, 322. 
stone  columns,  291. 
Shale, 
blue,  248. 

clay  in  brick  making,  322. 
clay  soils,  7. 
Shape,  bricks,  311. 
Shear, 

slates,  897. 
resisting,  645. 
vertical,  645,  649. 
concrete,  600. 

beams,  reinforced,  664, 
Shear     failures     in     reinforced  concrete 

beams,  649. 
Shearing  strength  (see  strength,  shearing). 
Shearing  stress  (see  also  stress). 

steel,  in  reinforced  concrete  beams,  660. 
Sheathing  lath  (see  lath,  sheathing). 
Sheds,   drying,   brick  manufacture,  314. 
Sheet-metal  lath   (see  lath,  sheet-metal). 
Sheet  piling, 

steel,  interlocking,  86. 
use  in  masonry  wells,  73. 
Shingles,  wood,  244. 
Shoes,  for  wooden  piles,  28. 
Shop  drawings,  concrete,  reinforced,  speci- 
fications, 856. 
Shores,  concrete,  reinforced,  specifications. 

851. 
Shoring,  24. 

employment  of,  120. 
removal  of  foundation,  120. 

responsibility,  n8. 
spacing  of,  120. 
support  of  wall  by  struts,  119. 
Shoring,   needling  and  underpinning,  118. 
Shoved  work,  brick  laying,  336,  337. 
Shovels,  steam,  mining  brick  clay,  313. 
Shrinkage, 
bricks,  327. 

clay  in  brick  manufacture,  312. 
brick  backing,  299. 
wood  girders,  295. 


Shrinkage  cracks,  concrete,  602. 

rods,  reinforced  concrete  retaining  walls, 
105. 

Shutter-eyes,  fire-proof  shutters,  768,  769. 
Shutters, 
steel,  582. 

wood,  tin-covered,  582. 
Side-and-end  construction,   floor  tile,  flat- 
arch,  480. 

Side-construction,  floor  tile,  flat-arch,  477. 
Side-cut  bricks,  315. 

Sidewalk,  Sidewalks  (see  also,  pavements), 
construction,  with  terra-cotta  facade,  420. 
curbing,  118. 

floor-arches,  segmental,  472. 
Portland  cements,  use  in,  171. 
stone,  supports  in  localities  affected  by 
frost,  116. 
thickness  relative  to  length  of  stones, 
116. 

top  surface,  proportions  of  cement  and 
sand  in  mortar,  190. 
Sidewalk  vaults,  roofs  of,  114. 
Silica,  brick  manufacture,  312. 
Silica-cement  (see  cements,  169). 
Silica  sand,  bricks,  sand-lime,  329. 
Silicate  of  alumina  bricks,  312. 
Silicate  artificial  stone,  261. 
Sills, 

concrete  block  construction,  864. 
concrete,  reinforced,  742,  864. 
concrete,  specifications,  861. 
door,  stone,  298. 

setting,  301. 
lug,  280. 
settlement,  280. 
slip,  100,  280. 
stone,  267,  280,  298. 

breaking  by  settlement,  100. 

building  ends  into  walls,  278,  279. 

continuous,  299. 

cracking  or  breaking,  298. 

granite,  dressing,' 274. 

joints  of,  298. 

protecting,  301. 

under  stone  tracery,  298. 
terra-cotta,  419,  835. 
washes,  280. 

window,  stone,  276,  298. 

scant,  309. 

setting,  301. 
Silt,  foundations  on,  9. 
Simplex  concrete  piles,  43. 
Six-cut  stone  finish,  274. 
Size, 

bond-stones  in  brick  piers,  294. 
bricks,  275,  311,  326, 
fire-bricks,  324. 
jambs,  stone,  266. 
quoins,  stone,  266. 
stone,  broken-ashlar,  265. 

coursed-ashlar,  265. 

economical  size  of,  275. 
templates,  stone,  295. 
Skeleton    construction    (see  construction, 

skeleton). 
Skew-backs, 

brick-arches,  381. 

cast-iron,  768,  769. 
concrete,   504,  505. 

advantages,  94. 
inverted  arches,  94. 
material,  94. 
placing,  94. 

tile,  465,  466,  475,  476,  477,  478,  479, 
480,  481,  485,  486,  488,  490. 
floor-arches,  467. 
types  of,  474,  475. 


INDEX. 

Skim  Coat,  Plastering^ — Specifications. 


955 


Skim  coat,  plastering,  783. 
Slabs,    bending  'moments,    reinforced  con- 
crete design,  662. 
cinder    concrete,     reinforced,  constants 

used  in  formulas,  656. 
concrete  floor,  718. 
reinforced,  662. 

determination  of  dimensions  of,  655. 
strength,  655. 
Stone,   strength  of,   306    (see   also  flag- 
ging). 

Slag  cements   (see  cements,  slag  and  ce- 
ments, Puzzolan). 
Slag  concrete  (see  concrete,  slag). 
Slaking,  quicklime  in  bricks,  312. 
Slate, 

carbonates,   amount   of,   in,   895,  896. 
characteristics,    comparative,     893,  894, 

89s,  896. 
chemical  composition,  886. 
classifications,  898,  899. 

trade,  245, 
clay  soils,  7. 

cleavage  surface,  893,  894. 

color,  893,  894. 

commercial  value,  897. 

corrodibility,  884,  897. 

cost,  897,  898. 

damp-proof  courses,  367. 

description  of  important,  245. 

expansion,  co-efficient  of,  897. 

fissility,  grades  of,  895,  896. 

foreign,  244. 

general  description,  241. 

heat-resistance,  536. 

lime,  amount  of,  in,  895,  896. 

luster,  893,  894. 

magnitite,  amount  of,  893,  894. 

minerals,  chief,  895,  896. 

modulus  of  rupture,  242,  305,  884,  897. 

physical  properties,  242, 

porosity,   884,  897. 

production,  243. 

properties,  893,  894,  895,  896. 

shear,  897. 

strength  of,  895,  896. 

compressive,  897. 

flexural,  897. 

shearing,  897. 
surface,  cleavage,  893,  894. 
tests,  897. 

texture,  microscopic,  893,  894. 

toughness,  895,  896. 

uses  of,  242. 

value,  commercial,  897. 

weight,  884. 
Slate    damp-proof   courses,    concrete  block 

walls,  742. 
Slate  roofing,  536. 

Slate  stair  treads  and  risers,  580,  581,  582. 

Slate  stones,  263. 

Slates,  ash,  898. 

Slates,  clay,  898,  899. 

Slates,  dike,  898. 

Slates,  fading,  898,  899. 

Slates,  igneous,  898. 

Slates,  mica,  898,  899. 

Slates,  roofing,  cost  of,  245. 

weight,  244. 
Slate,  unfading,  898,  899. 
Sleeves,  pipe,  concrete,  reinforced,  specifi- 
cations, 856. 
Sliding,  clay  soils,  inclined  layers  of,  7. 
Sliding  tendencies,  stones  in  masonry,  298. 
Slip,  bricks,  glazed,  320. 
Slip-joints,  walls,  joining,  302. 
Slip-sills,  100,  280,  366. 
Slop-molding,  brick  manufacture,  313. 


Smeaton,  John,  engineer  of  Eddystone 
lighthouse,  141.  . 

Smith  Wire  and  Iron  Works,  F.  P.,  Chi- 
cago, 111.,  columns,  concrete,  spiral 
wire  reinforcement,  699. 

Smoke-pipes,  metal,  384. 

Soap  and  alum  solution,  stonework,  water- 
proofing, 260. 

Soapstone,  248. 

Sockets,  concrete  girders,  reinforced,  7i7- 
concrete  girders,  reinforced,  specifications, 
85s. 

for   supporting   girder  frames,  concrete 
girders,  reinforced,  692,  694. 
Soffits,  arches  and  vaults,  281. 
Soft  soils,   foundations,   use  of  auger  m 

pipe  to  test  character  of,  4. 
Soft  stones,  dressing,  271. 
Soils,3.  ^  . 

bearing  power  of,  foundations,  10. 

clay,  foundations  on,  7. 

Colorado,  principally  clay  and  sand,  8. 

composition  of,  in  laying  foundations,  4. 

dry,  brickwork  in,  311. 

foundations  on  firm  soils,  i. 

heavy  blue  clay,  foundations,  7. 

loam,  foundations,  9. 

marshy  or  compressible,  foundations,  9. 
mud  and  silt,  foundations,  9. 
nature   of,  3' 

peculiar  nature,  foundations,  10. 

peculiarities  of,  foundations,  4. 

pressures,  unequal,  84. 

ramming  in  trenches,  24. 

soft,  foundations,  auger  used  in  pipe,  to 

test  composition,  4. 
testing  in  excavations,  24. 
testing,  municipal  regulations,  11. 
testing,  N.  Y.  State  Capitol,  Albany.  N. 

Y  13. 

Sooy    Smith,    Gen.    William,  sustaining 

power  of  piles,  34. 
Soft-mud  bricks,  314- 
Sound,  testing  granites  by  sound,  308. 
Soundness, 

cement,  natural,  845. 
Portland,  848. 

in  reinforced  work,  849. 
Sound-resistance,  partitions,  541. 
Spacing-bars,  columns,  concrete,  reinforced, 

696,  697,  706. 
Spalling,  bricks,  paving,  323- 
Spalls, 

cut-stone  arches,  310. 

cut-stonework,  298. 

rubble  work,  264. 
Spandrel, 

supports,  skeleton  construction,  75o- 

stone-arches,  28.';. 

stone-arches  and  vaults,  281. 

support  for,  in  stone  arches,  285. 
Spans,  flat  stone  arches,  288. 
Specific  gravity, 

bricks,  paving,  323. 

cement,    Portland,    irf   reinforced  work, 

849. 
granites,  883. 
Specifications, 

anchors  for  stonework,  823. 

ashlar,  822. 

ash-pits,  830. 

back-plastering,  837. 

balconies,  reinforced  concrete,  860. 

beams,  false,  tile,  833. 

brick  facing  in  reinforced  concrete,  860. 

bricks,  311. 

common,  824. 

fire-clay,  hollow,  826. 


956 


INDEX, 

Specifications — Stability. 


molded,  824. 

pressed,  824. 

stock,  824. 

wetting,  339. 
brickwork,  824. 

common,  825. 

ornamental,  825. 

protection,  825. 
cements,  natural,  154,  844. 

constancy  of  volume,  155. 
definition,  155. 

Engineer  Corps,  U.  S.  Army,  1901, 
845. 

fineness,  151,  155. 
neat,  strength  of,  155. 
'  New  York  State  Canals,   1896,  844. 
packages,  154. 

Rapid  Transit  Subway,   New  York 
City,  1 900- 190 1,  844. 

requirements,  154. 

sampling,  155, 

setting,  time  of,  155. 

specific  gravity,  155. 

strength,  tensile,  152,  155. 

tests,  155. 

weight,  154. 
non-staining,  139. 
Portland,  176,  847. 

American-made,  163. 

New  York  State  Canals,   1896,  848. 

Rapid-Transit    Subway,    New  York 
City,   1900-1901,  848. 
848. 

strength,  tensile,  176. 
weight,  172. 

Puzzolan,  182. 
cementing  outside  of  walls,  820. 

tile  roof  arches,  834. 
chimneys,  brick,  828. 
cinder  concrete  filling,  861. 
cleaning  brickwork,  830. 

st6ne\york,  824. 
cold-air  duct,  828. 
columns,  fire-proofing,  832. 

furred  and  wire-lathed,  841. 
concrete,  607. 

block,  865. 

footings,  818. 

freezing  weather,  602. 

hollow  blocks,  334. 

reinforced,  849. 

work,  632, 
concreting  tile  floor  arches,  834. 
copings,  concrete,  861. 
cornices,  false,  tile,  833. 

false,  wire  lath,  841. 

plaster,  838. 
cut-stone,  setting,  829. 
cut-stonework,  821. 
cutting  and  fitting  brickwork,  829. 
excavating,  816. 

false  beams  and  cornices,  tile,  633. 
field  rubble,  821. 
fire-proofing,  831, 

in  reinforced  concrete  work,  861. 
fire-walls,  829. 

floor   arches,   concrete,   ROebling  system, 
843. 

floors,  fire-proof,  832. 

floor  surfaces,  cement,  860. 

flue  linings,  828. 

footings,  concrete,  818. 

furring,   false  beams  and  cornices,  833. 

tile,  walls,  833. 
general  conditions,  814. 

considerations,  813. 
granite,  821. 
grouting,  827. 


hard  wall  plasters,  838. 
ironwork,  setting,  829. 
joints,  thickness  of,  335. 
lathing,  metal  lath,  836. 

wooden  lath,  836. 
laying  masonry  in  freezing  weather,  831. 
lintels,  reinforced  concrete,  859. 
lime  mortar,  827. 
Ihne-and-cement  mortars,  827. 
masonry  laid  in  freezing  weather,  198. 
mortar,  cement,  brickwork,  826. 

colored,  827. 

for  fire-proof  tiling,  832. 

lime,  827. 

stonework,  821. 

terra-cotta  trimmings,  835. 
outhouses,  830. 
partitions,  solid,  842. 

tile,  fire-proofing,  833. 
paving,  brick,  830. 
pent-houses,  834. 
piers,  stone,  820. 
piling,  wooden,  817. 
plastering,  837. 

outside  walls,  827. 
pointing  brickwork,  830. 

stonework,  824. 
protecting  brickwork,  825. 

cut-stonework,  301. 
relieving-arches,  827. 

Roebling  concrete  floor  arch  system,  843. 
roofs,   fire-proofing,  832. 
roof  surfaces,  fire-proof,  834. 
rubbish,  830. 

sand  finish,  hard  wall  plasters,  839. 

plastering,  838. 
sandstone,  822. 
setting  cut-stonework,  823. 
sills,  concrete,  861. 
solid  partitions,  842. 

specific  gravity  of  Portland  cements,  173. 
stairs,  reinforced  concrete, '860. 
steelwork,  setting,  829. 
stones  in  broken  ashlar,  height  of,  266. 

maximum  projection  of  stones  beyond 
face,  271. 
stonework,  818. 

finish,  269. 

patent-hammer  dressing,  274. 
rubble,  264. 
terra-cotta,  architectural,  834. 
setting,  830. 
trimmings,  834. 
testing  concrete  blocks,  865. 
thimbles  for  flues,  828. 
trimmings,  stone,  821. 

terra-cotta,  834, 
ventilating  openings  in  walls,  829. 
wall  furring,   tile,  833. 
walls,  foundation,  819. 
foundation,  rubble,  820. 
rubble,  821. 
stone,  exterior,  821. 
wire-lathing,  stiffened,  840. 
on  iron  work,  841. 
on  metal  furring,  839. 
on  steel  girders,  841. 
"Spiral"  expanded  metal  lath,  565,  567. 
Splitting,  stones,  263. 
Spread  footings,  94. 
foundations, 

economy  of,  25. 
materials,  48. 
Springers,  stone  arches,  281. 
Springing  stones,  285. 
Sprinklers,  automatic,  582. 
Square  of  slate,  definition,  244. 
Stability, 


INDEX. 


957 


stables — Steel  Beam  Footings. 


arch-rings,  284. 

arches,  stone,  281,  284. 

depending  on  footings,  93. 

retaining-walls,  depending  on  method  of 
filling,  104. 
reinforced  concrete,  104. 

rubble  stone  arches,  289. 

walls,  87. 
Stables,  walls,  thickness  of,  910. 
Staff,  800. 
Stains, 

brickwork,  340,  341. 

cut-stonework,  hemlock,  301. 

granites,  308. 

limestones,  301. 

marbles,  301. 

plasters,  hydraulic  paints,  469. 
pointing  mortars,  302. 
stonework,  from  drippings,  276. 
tile  floor  arches,  469. 
Stair,  Stairs, 
brick,  395,  579. 
circular  stone,  294. 
concrete,  reinforced,  580,  581,  582. 

specifications,  860. 
fire-proof,  classification,  579. 

general  description,  579.  *' 
ferroinclave,  580,  582. 
Guastivino  tile,  579. 
hanging  stone,  294. 
iron,  580. 
spiral,  396,  397. 
steel,  580. 

stone,  293,  294,  579. 

European  buildings,  293. 
government  buildings,  293. 

tile,  hollow  block,  579. 

treads,  safety,  860. 
Stair  treads  and  risers,  ferroinclave,  517. 

marble,  580,  581,  582. 

slate,  580,  581,  582. 
Stairways,  partitions,  549. 
Staking  out  buildings,  i,  2,  3,  23,  24. 

adjacent  lots,  3. 

city  buildings,  3. 

city  property  lines,  3. 

party-lines,  3. 

rules  for  contractor,  2. 
for  surveyor,  3. 

unit  measurements,  3. 

United  States  standard  measurements,  3. 
Standard  Concrete   Steel   Co.,   New  York, 
concrete  block  column  fire-proofing,  458, 
459- 

concrete,  reinforced,  type  of  construction, 
714. 

hollow  concrete  I-arch  construction,  529. 

metal  furring,  571. 
Standard  terra-cotta,  407. 
Standard,    measurements.    United  States, 

staking  of  buildings,  3. 
Stand-pipes,  582. 

concrete,  595. 
Static  equilibrium,  laws  of,  in  beams,  644. 
Steam,  cleaning  stonework,  302, 
Steam-hammer, 

for  driving  wooden  piles,  30. 

quality  of  wood  used  with,  30. 

rapidity  of  penetration  of  piles  under,  30. 
Steam  jet,  clay  moistening  in  brick  manu- 
facture, 317. 
Steam-shovels, 

clay  mining,  for  bricks,  316. 

mining  brick  clay,  313. 
Steel, 

adhesion  to  concrete,  660. 
compressive  stress  in  columns,  717. 
elastic  limit,  617,  699. 


elongation,  elastic,  679. 
expansion,  coefficient  of,  679. 
fiber  stress,  safe  unit,  62. 
grades  used  in  reinforced  concrete  work, 
677. 

hard  bridge  steel,  677. 
heat  resistance,  447. 
high  carbon  steel,  678. 

structural,  combined  with  reinforced  con- 
crete construction,  715. 
fire-proofed     in     reinforced  concrete 
work,  861. 

high  carbon  reinforcements  for  concrete, 
522. 

working  unit  tensile  stress,  660. 

medium  stresses,  working,  678. 

modulus  of  elasticity,  660,  679. 

properties  of,  in  combination  with  con- 
crete, 679. 

shearing    stress    in    reinforced  concrete 
beams,  660. 

tensile    stress    in    reinforced  concrete 
beams,  660. 

working  stresses  for  reinforced  concrete 
work,  660,  677. 
Steel  angles,  under  stone  caps,  277. 
Steel  beams, 

bending  moments,  computing  maximum, 
61. 

depth,  proportion  to  weight,  67. 

grillage,   formula  for  maximum  bending 

moment,  62. 
grouted  under  concrete  floor  filling,  471. 
needling,  use  in,  121. 
protection  when  bedded  in  concrete,  59. 
relieving,  stone  arches,  285,  286. 
selection  from  tables,  excess  of  strength, 

64. 

under  stone  lintels,  277. 
Steel  beam  footings,  58. 

added  projection  to  beams,  63. 
bedding  base-plate,  59. 

stone  footing,  59.  ' 
combined,  67. 
comparison  of  costs,  58. 
concentration     of     weight    on  outer 

beams  of  upper  course,  60. 
concrete  between  layers  of  beams,  58. 
continuity  of  action  between  steel  and 

concrete,  59. 
depositing  concrete,  58. 
depth  of  bearns  in  lower  course,  60. 
determining  size  of  beams,  61. 
economy  in  using  deep  beams,  59. 
example  on  solid  rock,  60. 

under  a  pier,  66. 

under  wall,  64. 
excess  strength  in  upper  tier,  67. 
filling  between  beams,  58. 
general  design,  58. 

grillage  capping,  for  wooden  piles,  ex- 
pense, 30. 
layers  of  beams,   58,  59. 
levelling  beams,  58. 
manner  of  spreading  load,  60. 
mixture  of  concrete,  58. 
number  of  beams  in  upper  course,  60. 
painting  beams,  59. 
placing  beams,  58. 
plastering  outside   of  footing,  59. 
preparation  of  ground,  58. 
prevention  of  beams  breaking  through 

concrete,  60. 
railroad   rails,  59. 
spacing  of  beams,  58. 
supporting    several    unequally  loaded 

columns,  67. 
supporting  two  or  more  columns,  67. 


958 


INDEX. 


Steel-concrete — Stone  Base-courses. 


symmetrical    arrangement    of  beams, 
67. 

table  of  safe  loads  on  beams,  65. 

tendency  of  beams  to  crush  masonry 
footing,  63. 
Steel-concrete    (see  concrete,  reinforced). 
Steel  framing,  fire-proof  floors,  464. 
Steel  lintels  (see  lintels,  steel). 
Steel  reinforcement,  concrete,  677. 
Steel  relieving-beams,  stone  arches,  285. 
Steel  stairs,  580. 

Steel  supports  for  masonwork,  747. 
Steel  supports  for  stone  lintels,  279. 
Steel  tape,  use,  in  staking  out  buildings,  3. 
Steel   wells,  use   in  marshy  soils,  founda- 
tions, 9. 

Steel    wire,    spiral   reinforcement   of  con- 
crete columns,  699. 
Steel   wire  floor   reinforcement    (see  rein- 
forcements), 
Steel  work, 

setting,  specifications,  829. 
wire  lath  covered,  841. 
Step,  steps, 
area,  113. 

hanging  stone,  294. 
stone,  293. 

granite,  dressing,  274. 
Stepped  footings,  88. 
Stiffened  wire  lath,  561,  562,  563. 
Stiff-mud  bricks,  314. 
Stilted  arch,  281,  283. 

Romanesque  architecture,  283. 
Stirrups,  concrete,  reinforced,  51,  664,  686, 
687,  688,  689,  691,  692,  693,  694,  699. 
704,  70s,  706,  707,  708,  709,  711,  712, 
713.  716. 
Stock  bricks  (see  bricks,  stock). 
Stone,  Stones   (see  also,  stonework), 
absorption,  ratio  of,  881,  882,  883,  891. 

tests  for,  257. 
acid  tests,  258. 
artificial,  260,  594. 

absorption,  ratio  of,  891. 
Portland  cements,  163. 
weight,  891. 
atmosphere,  effect  of,  249,  252. 
backing,  300. 
bearing,  295. 
bond  (see  bond-stones), 
broken,    concrete,    reinforced,  specifica- 
tions, 857. 
with  concrete,  rock  fissures,  6.  Fig.  5. 
buildings  of  stone,  lists  of,  887.  889,  890. 
chemical  composition,  884. 
classification,  212. 
climate,   effect  of,  250. 
color  of,  254. 
cobble,  97. 

compactness,  tests  for,  257. 
concrete,  artificial,  261,  ^262. 
conglomerates,  263. 
copings,  suitable  for,  112. 
cost  of,  255. 

dimension  (see  dimension-stone), 
distribution,  geographical,  209. 
durability.   251,  311. 

field,  used  as  drains,  clay  foundations,  8. 
foundations,  porosity,  96. 
fracture,  tests  for,  257. 
hard,  dressing,  272. 
hardness  of,  255. 

heat-resistance,   256,   440,   579,  891. 
laminated,  96,  295. 

backing.  300. 

beds  of,  96. 

beams,  caps,  lintels,  305. 
lava,  247,  2"5o. 


location    of    building    affecting  choice, 
250. 

manufactured,  260. 
minerals  of,  211. 
miscellaneous,  247. 

monumental,  production,   1905- 1906,  208, 
209. 

natural  bed,  99. 
new,  249. 

oxidation,  durability,  affected  by,  252. 
paving,   production,   1905-1906,   208,  209. 
porosity,  251. 

production,  amount  in  1896  to  1906,  205. 
classification,  206. 

in  1905  and  1906,  rank  of  States  in, 
880. 

rank  of  States  and  territories  in,  207. 
rough    and    dressed,    1905    and  1906, 
208,  209. 

value  of,  for  different  purposes,  208. 
in  1896  to  1906,  205,  207. 
+      various  kinds,   1905   and   1906,  878, 
879. 

quarry-water,  259. 
sand-lime,  261. 
sawed,  ashlar,  296. 
iseams  in,  308. 
seasoning  of,  258. 
selection  of,  249. 
setting  large  stones,  300. 

manner  of,  253. 
size  of,  for  economy,  275. 

in  ashlar,  265. 
soft,  dressing,  272. 
solution,  durability,  affected  by,  252. 

tests,  258. 
shale,  248. 

sizes  for  reinforced  concrete  aggregates, 

675. 
slate,  263. 
splitting,  263. 
stratified  for  lintels,  278. 
strength  of,  255. 

for  bond  stones,  294. 
subject  in  general,  205. 
temperature  changes,  effect  of,  250. 
testing  weathering  qualities,  249. 
tests  in  general,  256. 
trap,  248. 
tuffs,  247. 
turfa,  247. 

wall  facing,  released,  590. 
weathering  of,  249. 

weight,    strength   and   absorption,  tables 
of,  88r,  882,  883,  891. 
Stone  and  brick  buildings  erected  in  United 

States  in  1906,  901. 
Stone-and-concrete  footings,  88. 
Stone  arches,  280. 

backing,  284. 

built-up,  284. 

cost  ofj  283. 

cracks  in,  285. 

elliptical,  285. 

flat,   288,  289. 

label-moldings,  284. 

relievinp-beams,   over,  285. 

spandrels,  285. 

spanning  rock  fissures,  foundations,  6. 
stability  of,  281,  284. 
strength  of,  283. 
thickness  of,  284. 
Stone  architraves  (see  architraves,  stone), 
292. 

Stone  ashlar,  over  stone  lintels,  277. 
Stone  backing  (see  backing,  stone). 
Stone  base-courses,  vermiculated,  274. 
Stone  buildings,  lists  of,  887,  889,  890. 


INDEX. 

stone  Cnps — Strength. 


959 


Stone  caps,  267,  277. 

Stone  carving   (see  carving,  stone). 

Stone  columns  (see  columns,  stone). 

Stone  concrete   (see  concrete). 

Stone  copings   (see  copings,  stone). 

Stone  cornices  (see  cornices,  stone). 

Stone-cutting, 

broken  ashlar,  265. 

terms  used,  281. 
Stone-cutting     and     dressing,  government 

work,  274. 
Stone-cutting  and  finishing,  269. 
Stone-cutting  tools.  269. 
Stone  doorsteps,  280. 
Stone  drains, 

draining  water  from  rock,  foundations,  5. 

footing,   drains,  24. 

foundations  in  clay,  8. 
Stone  dwellings   (see  dwellings,  stone). 
Stone  entablatures  (see  entablatures,  stone). 
Stone-finishing,    different    kinds,    253,  271. 
Stone  footings,  89. 

dimension  stone,  819. 

economy,  89. 

effect  of  water  on,  107. 

example  of  offsets,  91. 

heavy,  90. 

measurement  of,  306,  307. 
projection  of  footing  course,  89. 
rubble,  819. 

thickness  and  width,  89. 
Stone   friezes   (see  friezes,   stone),  292. 
Stone  jambs, 

cutting  and  rubbing,  267. 

size  of,  266. 
Stone  lintels  (see  lintels,  stone). 
Stone  moldings,  267. 
Stone  mullions  (see  mullions,  stone). 
Stone  pavements,  115. 

bed  for  laying,  116. 

joints,  116. 
Stone  piers  (see  piers,  stone). 
Stone  porches  (see  porches,  stone),  292. 
Stone  quoins, 

size  of,  266. 

vermiculated,  274, 
Stone  screenings, 

color  as  affecting  concrete  blocks,  744. 

concrete  blocks,  730,  731. 
Stone  sidewalks  (see  sidewalks,  stone). 
Stone  sills  (see  sills,  stone). 
Stone  slabs, 

joints,  114. 

to  form  roofs  of  sidewalk  vaults,  114. 
Stone  stairs  (see  stairs,  stone). 
Stone  steps  (see  steps,  stone). 
Stone  templates  (see  templates,  stone),  294. 
Stone  threshholds,  280. 
Stone  trimmings,  267. 

brick  buildings,  275. 
Stone  vaults,  280. 
Stone  walls  (see  walls,  stone). _ 
Stone  washes,  cutting  and  rubbing,  267. 
Stonework   (see  also,  stone,  stones). 

ashlar,  264. 

backing,  proportions  of  cement  and  sand 

in  mortar,  190. 
below  grade,  use  of  cement  mortars,  188. 
broken  ashlar,  265. 
cleaning,  824. 
cost,  306,  307, 
cut-stonework,  cost  of,  275. 
classification,  263. 
damp-resistance,  260, 
dressed,  laying,  out,  275, 
facing,  264. 

bv  disintegration  of  mortar,  196. 
foundations,  311. 


Gothic,  298. 
hammer-dressed,  264. 
honeycomb  dressing,  275. 
inspection  of  erected  work,  108. 
laying  in  freezing  weather,  831. 
loads  on,  safe,  907. 

moistening  of  stones  in  hot  weather,  197. 
mortar,  natural  cements,  147. 

proportions  of  cement  and  sand,  189. 
oiling,  259. 

openings,  in  estimating  cost,  307. 

painting,  259. 

pointing,  824. 

preservation  of,  259. 

protection  during  erection,  259. 

Ransome's  process  of  water-proofing,  260, 

rock-faced   in   broken   ashlar,  263. 

rough,  sand  for  mortar,  132, 

rubble,  263. 

amount  of  cement  mortar  required  per 

perch.  194. 
proportions  of  cement  and  sand  in  mor- 
tar, J  90. 
soiling  by  drippings,  276. 
specifications,  818. 
trimmings,  263. 
washes,  276. 
water-proofing,  260. 
Stool-lock  bar  spacers,  concrete,  reinforced, 

688,  690,  691. 
Stopping  work,  concrete,  reinforced,  speci- 
fications, 858. 
Storage,  cement,  849. 

Store  windows,  stone  lintels  over,  279. 
Stores,  walls,  thickness  of,  910. 
Story  heights,  mercantile  buildings,  362. 
Stove  lining,  tile  production,  value  of,  903, 
905- 

Stratified  stone,  lintels,  278. 

Street  lines,   staking  out  buildings,  3. 

Streeter,  H.  A.,  Chicago,  111.,  clips  for  sus- 
pended ceilings,  540. 

Streeter  patent  clips  for  suspended  ceilings, 
540. 

Strength, 

adhesive,    reinforcing   bars   in  concrete, 
666. 

arches,  brick,  335. 

stone,  283. 
backing,  stone  and  brick,  300. 
bearing,  foundation   rocks  and  soils,  10. 

piles,  testing,  29. 
wooden.  30. 

sand-filled  made   land,  9. 
bond-stones  in   brick  piers,  294. 
bricks,  312,  313,  323,  326,  328. 

arch-bricks,  324. 

pressed,  325. 

sand-lime,  332. 
brickwork,  335. 

crushing,  401. 

effect  of  moisture,  340. 
cement  bricks,  334. 
centers  for  arches.  289,  291. 
chimneys,  radial  block,  325. 
cohesive,  brick  materials,  317. 
columns,    reinforced   concrete,  longitudi- 
nally reinforced,  668. 

reinforced  concrete,  wrapped  or  hooped, 
672. 

stone,  303.  304- 
compressive,    bricks,    dry-pressed,  317. 
cement  bricks,  334. 
concrete,  590,  600. 
blocks,  868. 
tests_  for,  867. 
piers,  bricks,  906. 
slates,  897. 


960 


INDEX. 

stress — System  M. 


concrete,  598. 

blocks,  740.  , 
concretes  in  reinforced  construction,  670. 
crushing,  bricks,  paving,  323- 

bricks,  sand-lime,  332. 

brickwork,  328,  401. 

columns,  stone,  304- 

concrete,  598. 
blocks,  863. 

granites,  881,  883. 

limestones,  881,  882,  883. 
Indiana,  228. 

marble,  882,  883. 

piers,  brick,  906. 

sandstone,   Connecticut  brown,  238. 
stones,  255,  881,  882,  883. 
stone  piers,  303. 
cut-stonework,  303.  304,  30S,  300. 
diagonal  tension,  concrete,  601. 
clastic  limit,  concrete,  601. 
ferroinclave  steel  sheets,  5i7- 
flagstones,  306. 
flat  stone  arches,  288. 
flexural,  beams,  stone,  305- 
caps,  stone,  305. 
concrete  blocks,  868. 
lintels,  stone,  305- 
slates,  897- 
floor  arches,  brick,  467- 

reinforced  tile,  489,  492,  493- 
tile,  segmental,  476. 
flocrrs,  concrete,  flat-arch,  Koeblmg,  512. 
footings,   reinforced  concrete,  52. 
Guastavino  tile-arches,  496. 
lintels,  cast-iron,  750. 

stone,  278,  303- 
partitions,  541. 
piers,  brick,  335« 

stone,  303. 
fiafe,  stone  piers,  303-         _    .  , 
bearing    strengths,     foundation  rock. 

and  soils,  table,  10. 
wooden  piles,  table,  3i« 
sandstone,  882,  883. 
shearing,  concrete,  600. 
slabs,  concrete,  reinforced,  655- 
slates,  242,  895,  896,  897. 
stone  slabs,  306. 
stone  templates,  295. 
stones  for  building,  255. 
tensile,  cement,  natural,  844,  04b. 
Portland,  848. 

in  reinforced  work,  850. 
concrete  599- 
terra-cotta,  architectural,  422 
transverse  or  flexural,  modillions,  terra 

cotta,  423- 
transverse,  walls,  brick,  328. 
iiltimate,  stone  piers,  303- 
walls,  brick,  335-  , 

depending  upon  bonding,  97- 
on  mortar,  97. 
woods,  constant  for,  70. 
working,  stone  piers,  303- 
Stress, 

beams,  concrete  graphical  representation 
of  compressive   stresses,  651. 

experimental  laws,  646. 

lines  of  principal  stress,  646,  647. 

theoretical  laws,  644. 
concrete,  reinforced,  allowable,  50. 

reinforced,  structural  members,  643- 
working  unit  stress,  659. 
flexural,  stone  sills,  298. 
shearing,  vertical,  concrete  beams,  664. 
tension,  diagonal,  concrete  beams,  664. 
transverse,  stone  sills,  298. 


working  unit-stresses,  reinforced  concrete, 
659. 

Stress-strain  curve  beams,  reinforced  con- 
crete, 649. 
Striking  joints,  brickwork,  337. 
String-courses, 

brick,  341,  342. 

joints  in  stone,  299. 
Strips,  floor,  wooden  floors,  fire-proof,  470, 

471.  , 
Stuccowork, 

exterior,  797,  799. 

interior,  792. 
Stuck  mortar  joints,  264. 
Structural  columns,  rock  foundations,  6. 
Studs, 

allunited,  for  metal-and-plaster  partitions 

555,  556. 

Berger   prong-lock,   for  metal-and-plaster 

partitions,  555. 
metal,  552,  553,  554,  556,  557,  558,  565, 

566,  571,  573. 
partitions,  solid,  842. 
rib-studs  for  metal-and-plaster  partitions, 

556,  (see  also  rib-lath). 
Submarine  work,  concrete,  595. 
Subsoil  drains,  clay  soils,  7. 

Subway,  New  York  City,  specifications  for 
natural  cement,  844. 
specifications  for  Portland  cements,  844. 
Subways,  concrete,  595. 
Sugar,  in  mortars,  197. 
Suggestions  in  brickwork,  345. 
Sulphur,  concrete,  cinder,  corrosion,  726. 
Sulphuric  acid, 

anhydrous,  cement,  Portland,  ,reinforced 
work,  850. 

use  in  detecting  lime  in  brick  clay,  312. 
Superintendence  (see  also  inspection), 
brickwork,  311,  403. 
building-lines,  23. 
cementing  walls  below  grades,  24. 
concrete  mixtures,  106. 
concrete,  reinforced,  qualifications  needed 

in  inspectors,  727. 
cut-stonework,  308. 
footings,  106. 
foundation  walls,  108. 
foundations,  23,  106. 
grade  marks,  24. 
lathing  and  plastering,  809. 
lime,   rejection  of  air-slacked,  135. 
mortar,  proportions  of  cement  and  sand, 
190. 

pointing  below  grade,  24. 

Superintendent,    responsibility    of,  staking 
out  buildings,  2. 

Supporting  power, 

of  clay,  increased  with  sand  or  gravel, 

foundations,  8. 
of  sand,  foundation  beds,  9. 

Surface  patterns,  brick,  345. 

Surface  ornament  (see  ornament,  surface). 

Surface  water,  draining  off,  rock  founda- 
tions, 5. 

Survey,  official,  staking  out  city  buildings, 
3. 

Surveyor,  rules  for,  staking  out  buildings, 
3. 

Suspended    ceilings     (see    ceilings,  sus- 
pended). 
Suspension  bridges, 

Brooklyn,  quality  of  foundation  soil,  12. 

Cincinnati,  quality  of  foundation  soil,  12. 
Syenite,  215. 

Sylvester's  process  of  water-proofing  brick 

walls,  400. 
System  M  (see  concrete,  reinforced). 


« 


INDEX. 


961 


T-beams — Thrust. 


T 

T-beams  (see  beams). 

T-Rib  brick  and  concrete  floor  arch  (see 
floors,  fire-proof). 

T-Rib  floor  arch  system,  467, 

Tall  buildings  (see  buildings,  high  and  of- 
fice-buildings). 

Tanks, 

concrete,  595. 
reinforced,  636. 

Tape, 

steel,  use  of,  staking  out  buildings,  3. 
Tar,    coal-tar    pitch,    damp-proofing  brick- 
work, 4^6 1. 
Tar-coated  anchors,  300. 
Tar  roofing,  536. 

Taylor,  W.  Purves,  cement  testing,  150. 
Taylor  &  Thompson,  choice  of  cements  and 
selection  of  brands,  160. 

color  of  Portland  cements,  172. 

comparison  of  strength  of  cements,  187. 

data  on  weights  of  cements,  etc.,  157. 

fineness  of  natural  cements,  151. 

fineness  of  Portland  cements,  175. 

fundamental  laws  of  strength  of  mor- 
tars, 190. 

mixtures  of  Portland  and  natural  ce- 
ments, 147,  191. 

mortars  with  various  admixtures,  197. 

natural  cements,  specifications,  154. 

Portland  cements,  170. 

Portland  cements,  specifications,  176. 

tests  for  soundness  of  Portland  cements, 
174. 

Teil,  France,  hydraulic  limestone,  138. 

Lafarge  cement,  138. 
Temperat..re, 

effect  on  building  stones,  250. 

effect  on  mortars,  197. 
Templates,  stone,  294,  295. 
Temporary  buildings,  foundations  for,  70. 
Ten-cut  stone  finish,  274. 
Tenement-houses, 

computing  weight  on  footings,  16. 

walls,  thickness  of,  908. 
Tensile  strength  (see  strength,  tensile). 
Tension, 

diagonal,  concrete  beams,  reinforced,  664. 

in  concrete  beams,  648,  649,  650,  660. 
Terra-cotta, 
anchors,  836. 
belt-courses,  835. 
brick  cornices,  344. 
caps,  windows,  835. 
cleaning  down,  836. 
color  of,  408. 
composition,  405. 
construction,  311,  412,  417. 

examples  of,  424. 
cornices,  835. 
cost  of,  422. 
cutting  and  fitting,  836. 
designing,  412. 
durability,  411. 
facing,  835. 

for  reinforced  concrete  lintels,  718. 
full-glazed,  407,  408. 
inspection  of,  412. 
jambs,  835- 
glazed,  407,  408. 
heat-resistance,  434,  441,  443. 
kilns  for,  319. 
laying  out,  412. 

mantels,  391.  392,  393,  394,  395. 

manufacture,  405. 

time  required,  421. 
mat-glazed,  407,  408. 


modelling,  835. 

mullions,  835. 

pointing,  421. 

polychrome,  407,  408. 

production,  value  of,  903,  905. 

prominent  buildings  in  which  polychrome 

terra-cotta  has  been  used,  410. 
protection  during  construction,  423,  836. 
setting,  421. 
specifications,  830. 

standard,  407.  « 

strength,  422. 

surface,  treatment  of,  407. 

time  required  in  making,  421. 

use  of,  410. 

vitreous-surfaced,  407,  408. 
wall  facing,  released,  590. 
weight,  422. 
Terra-cotta   lumber,   production,   value  of, 
903. 

Test,   Tests   (see   also  experiments), 
acid-resistance,  bricks,  sand-lime,  332. 
adhesion  between  steel  and  concrete,  665. 
Austrian  tests  for  floor-arches,  476. 
bearing  of  wooden  piles,  34,  35. 
bricks,  ringing  sound,  328,  331. 

sand-lime,  332. 
British  Fire  Prevention  Committee,  461. 
cements,  strength,  182. 
cement  in  reinforced  work,  849. 
concrete  blocks,  740,  863,  864,  865,  866. 
corrosion,  reinforcing  metals  in  concrete, 

fir«,  sand-lime  bricks,  332. 

floors,  fire-proof,  standard,  461. 

heat-resistance,  reinforced  concrete,  723. 

mixture    of    Portland    cement    and  hy- 
drated  lime,  131. 

pulling-out  tests,  rods  in  concrete,  666. 

sand-lime  products,  261. 

slates,  897. 

soils,  excavations,  24. 

municipal  requirements,  11. 

stone  piers,  strength  of,  303. 
crushing  strength,  255. 

strength,  foundation  bed,  methods,  12. 
Test    borings,    for    character    of  original 

soil,  foundations,  4. 
Test  cubes,  concrete,  reinforced,  specifica- 
tions, 857. 

Test  machines  for  bearing  power  of  foun- 
dation soils,  13. 
Texas,  cements,  natural,  143. 
Textile    Machine    Works    buildings,  con- 
crete, reinforced,  721. 
Texture,  bricks,  312. 
Thatcher  bar,  684. 

pulling-out  tests,  666. 
Thatcher  concrete  floor  unit  system  (see 

floors,  fire-proof). 
Thawing,  effect  on  clay  soils,  7. 
Theaters,  walls,  thickness  of,  910. 
Thickness, 

rubble  field  stone  walls,  264. 

walls,  brick,  326,  360- 
Thimbles  for  flues,  specifications,  828. 
Thompson,  Sanford  E.,  forms  for  concrete 
construction,  612. 

natural  cements,  specifications,  154. 

Portland  cements,  specifications,  176. 
Three-centered  arches,  286. 
Three-quarter  bond,  strength  of,  99. 
Thresholds,  stone,  280. 
Thrust, 

arches,  285. 

floor  arches,  brick,  466. 
tile,  flat,  485. 
segmental,  475. 


962 


INDEX. 


Tie-rods — Tuffs  Stone. 


Tie-rods, 

floor  arches,  brick,  466. 

tile,  segmental,  475- 
Ties, 

ashlar,  300. 

coping  stones,  293. 

metal,  stone  voussoirs,  284,  285. 

wall  veneering,  737,  738. 
railroad,  concrete,  595. 

concrete,  reinforced,  636. 
relieving-beams,  285. 
stone  entablatures,  292. 

porches,  292. 
wall,  351.  352,  372,  375. 
Tile,  Tiles, 

beam  and  girder  protection,  531. 

ceiling,  539,  540. 

clay,  fire-proofing,  columns,  449. 

heat-resistance,  441. 

roofing,  536. 
clay,  heat-resistance,  536. 
dense,  442. 

drain,   protection,  value  of,   903,  905. 
fire-proof,  production,  value  of,  903,  905- 

floors,  467. 
floor-arch,  segmental,  472. 
floor,   production,  value  of,   903,  905. 

surface,  472. 
Guastavino  (see  Guastavino). 
hollow, 

block,  stairs,  579. 

wall  construction,  583,  584,  585,  586. 

building  production,  value  of,  903,  905- 

used  with  reinforced  concrete,  707,  710. 

fire-proof   walls  for   dwellings,  583. 

loads  on,  safe,  907. 
metal,  roofing,  536. 
porous,  442. 

effect  of,  frost,  469. 
production,   value   of    (not   drain),  903, 
905. 

reinforced,   floot  arch,   flat  construction, 
488. 

Roman  size,  327. 

roofing,  production,  value  of,  903,  905. 
semi-porous,  443. 

sewer,  production,  value  of,  903,  905. 

wall,  production,  value  of,  903,  905. 
Tile-and-concrete    systems    of    floor  con- 
struction, 709,  710,  711,  713- 
Tile  baseboards,  molded,  hollow,  578. 

drains,  for  footings,  24. 

use  of,  foundations  on  clay  soils,  8. 
Tile  filling  blocks  for  floors,  472,  483. 
Tile  flooring,  533. 
Tile  furring,  832. 

Tile  grounds  for  cornices,  577,  578.  ^ 
Tile   interior  molded   hollow   door  jambs, 
578. 

Tile  molded  door  and  window  casings,  578. 
Tile  partitions  (see  partitions). 
Tile  picture-molding,  molded,  hollow,  578. 
Tile  skew-backs  (see  skew-backs). 
Tile  stove  lining,  production,  value  of,  903, 
905. 

T.   I.   M.   patent  reinforced  concrete  col- 
umns, 701,  702. 
Timber  (see  also  wood). 

below  water  line,  38. 

scarcity  of,  311. 
Timber  footings, 

best  woods,  68. 

buildings  of  moderate  height,  68. 
drift-bolting,  71. 
example,  70. 

filling  between  timbers,  68. 
planking,  68. 

platforms  for  columns,.  71. 


sizes  of  cross  timbers,  formula,  70. 

spacing  of  timber,  68. 

water  level,  68. 
Times  building.  New  York,  filled-in  rock 

fissures,  foundations,  6. 
Tin  roofing,  536. 

Toilet-rooms,    brick    facing,    glazed  and 

enamelled,  322. 
Tool-chisels,  271. 
Tooled-work,  272. 
Tools, 

pointing  jointer,  302. 

rubble  quarrying  and  dressing,  269. 

stone-cutting,  269.  ' 

stone-dressing,  271. 
Tooth-axe  for  stone  dressing,  270,  271. 
Tooth-chisel,  271. 
Tooth-chiselled  work,  272. 
Toothing,  brickwork,  359. 
Toughness,  bricks,  paving,  323. 
Tower,   high,   adjoining  lower   wall,  foot- 
ings, 19. 
Tower  walls,  slip-joints  for,  302. 
Towers,  concrete,  reinforced,  636. 
Tracery,  stone,  298,  299. 
Transverse  stress   (see  stress,  transverse). 
Trap  rock,  248. 

production,    1896-1906,    205,  206. 
Trap  rock  sand,  112.  . 
Treads,  Mason  safety  treads,  860. 
Trench,  Trenches, 

excavated  below  proper  levels,  24. 

extra  masonry  for  too  deep,  24. 

filled  with  sand  for  foundation  bed,  9. 

filling  in,  behind  foundation  walls,  108, 
III. 

for  concrete  footings,  88. 
heavy  buildings,  24. 
levels  for,  24. 

outside  wall,  foundations  in  blue  clay.  8. 

ramming,  24. 

water  in,  24. 
Triangular  mesh  steel  fabrics,  558." 
Trim, 

door    partitions,    metal-and-plaster,  552, 
553,  554. 

wood  fastening  to  concrete  block  walls, 
746. 

Trimmer  arches,  fire-places,  388,  390. 
Trimmings, 

cut  stone,  267. 

pitching  off,  267. 

sandstone,  822.  _ 

stone,  specifications,  821. 
brick  buildings,  275. 

stonework,  263. 

stone,  measurement  of,  307. 
Truss  bars  (see  concrete,  reinforced). 
Truss-coN  wall-hangers,  357. 
Truss  metal  lath,   reinforcement  for  con- 
crete partitions,  558. 
Truss  Metal  Lath  Co.,  New  York,  Kiihne's 
clincher  lath,  568. 

metal-and-plaster  partitions,  558. 
Trussed  Concrete  Steel  Co.,  Detroit,  Mith., 
columns,  concrete,  hooped,  696,  697. 

cup  bar,  681. 

furring  studs,  571. 

Kahn  bar,  685. 

rib-lath,  568. 

rib-studs,  556.^ 

trussed  bar  reinforcement,  699. 
Trussed  roofs  (see  roofs). 
Trusses, 

fire-proofing,^  S3S,  536. 

concrete,  reinforced,   720,   721,  722. 
Tudor  arches,  287. 
Tuffs  stone,  247. 


INDEX. 

Tunnels,  Concrete — ^\%'^all,  W  alls. 


Tunnels,  concrete,  595. 
Turfa  stone,  247. 

Turneaure  &  Maurer,  "Principles  of  Rein- 
forced Concrete  Construction,"  650. 

Turner,  C.  A.  P.,  concrete,  reinforced, 
types  of  construction,  mushroom  sys- 
tem, 713. 

Twentieth  century  wall  plaster,  789. 

Twisted  bars, 

reinforcing  concrete,  tensile  strength,  49. 
square  for  reinforcement,  56. 

Twisted  iron  tension  bars,  table  of  propor- 
tions and  strength  of  concrete  footings, 
S6. 

Two-piece  concrete  blocks  (see  concrete 
blocks) . 


Ultimate  strength  (see  strength,  ultimate). 
Underpinning,  118. 

bracing  and  supporting  walls,  122. 

cantilever,  125. 

granite  posts,  122. 

in  firm  soils,  122. 

light  buildings,  121. 

new   footings   extended  below   those  of 

adjoining  property,  86. 
removal   of   needles   and   shores,  123. 
wedging,  122. 
Undressed  masonry  beds  and  joints,  264. 
Unequal  settlement,  causes,  foundations,  15. 

different  levels,  foundations,  6. 
Unfading  slates,  898,  899. 
Unfibered  cement,  789. 
Union  wall  plaster,  787,  789. 
Unit  column  frame,  concrete  column  rein- 
forcement,  699,  701. 
Unit  Concrete  Steel  Co.,  Chicago,  111.,  re- 
inforcements   for    concrete  columns, 
699. 

Unit  concrete  steel  frame  (see  concrete,  re- 
inforced). 

Unit  Concrete  Steel  Frame  Co.,  Philadel- 
phia,  Pa.,   unit  concrete   steel  frame, 
692. 

Unit  measurements,  staking  out  city  build- 
ings, 3. 
Unit  pressure,  48. 

Unit  system  of  concrete  floor  arches,  529, 
530. 

Unit   systems   of   reinforcement    (see  con- 
crete, reinforced). 
United  States, 

comparison   of   cement  rock  formations, 
141. 

compressive  tests  on  cements,  186. 
distribution  of  natural  cements,  141. 
first  natural  cements,  141. 
hydraulic  limes,  use  of,  138. 
manufacture  of  Portland  cements,  163. 
materials  for  Portland  cements,  166. 
United  States  Army, 

Engineer     Corps,     1902,     definition  of 
Portland  cements,  162. 
fineness  of  Portland  cements,  175. 
specifications,   natural   cements,  843. 

Puzzolan  cements,  182. 
strength  of  natural  cements,  153. 
United  States  Army  and  Navy, 

natural  cements,  specifications,  154. 
Portland  cements,  specifications,  177. 
United    States    Gypsum    Co.,    New  York, 

partition  blocks,  545. 
United  States  Reclamation  Service,  fineness 
of  Portland  cements,  175. 


United     States     standard  measurements, 

staking  out  city  buildings,  3. 
Universal  steel  corner-beads,   565,  566. 
Up-draft  kilns,  318. 

"U.  S.  G."  fibered  plaster  partition  blocks, 
545. 


Vats,  concrete,  595. 

Vault,  vaults, 
brick,  382. 

municipal   regulations   for,  115. 
pavement,  114. 
soffit  joints,  338. 
stone,  280. 

under  sidewalks,  114. 
Vauft  construction,  Gustavino,  495. 
Vault  walls, 

arched,  thickness  of,  106. 
with  partition  walls,  106. 

general  description,  106. 

steel  construction,  economy  of,  106. 
Veneer,  brick,  374. 

Veneered  construction,  brick   in  concrete, 
718. 

Veneered  walls,   concrete  blocks  veneered 

with  brick,  737,  738. 
Ventilating    openings    in    walls,  specifica- 
tions, 829. 
Ventilation, 

hollow  wall  air-spaces,  372. 
wall  spaces  and  rooms,  hollow  concrete 
block  construction,  732. 
Vermiculated  work,  274. 
Vertical  shear,   645,  649. 
Victor  wall  plaster,  787,  789. 
Virginia,  Balcony  Falls,  hydraulic  cement 

^  analysis,  145. 
Visintini  system  (see  concrete,  reinforced). 
Vitreous  surface  terra-cotta,  401,  408. 
Vitrifaction, 

bricks,  319,  326. 
paving,  322. 
Voids  in  stone  walls,  filling,  99. 
Voussoirs, 

anchors  and  ties,  284. 
cracking  of,  284. 
flat  arches,  289. 
joints,  false,  283. 
number  of,  284. 
stone,  281. 

depth  of,  283. 
joints,  281,  282. 

shape  of,  281.  | 
width  of,  283. 
V-rib  metal  wall  furring,  571,  572. 


W 

Walks,  cement   (see  cement  walks). 
Waiting-rooms,    brick    facing,    glazed  and 

enamelled,  322. 
Wall,  Walls, 

area  (see  area,  walls). 

ashlar,  264. 

ashlar-faced,  thickness  of,  300. 
bonding  together,  302. 
brick,  anchoring,  354. 

bonding  at  angles,  359. 

carrying  up  evenly,  358. 

construction,  348. 

corbelling  for  joists.  358. 

cracks  in,  365. 

damp-proof  courses,  366. 

damp-proofing,  399. 

furring  blocks,  374. 

heat-resistance,  44T. 

hollow,  367. 


964 


INDEX, 


Wall,  Walls — ^Water. 


interior  parts  of,  313. 

joining  new  to  old,  360. 

loads  on,  safe,  907. 

openings  in,  359. 
wide,  280. 

plastering  outside,  827. 

stability  of,  335. 

strength,  transverse,  328. 

thickness,  326,  360. 

wood  used  in,  364. 
brick-veneered  construction,  374. 
cementing  outside  of,  820. 
circular,  brick,  339. 
concrete,  brick-faced,  718. 
concrete  blocks,  863. 
concrete,  mass,  cost,  624,  625. 

mass,  dimensions  requisite  for,  622,  623. 
foundation  walls  for  sniall  buildings, 
623. 

materials,  quantities,  624,  625. 
thickness,  622,  623. 
cross,  loi. 

curtain  (see  curtain-walls), 
dwarf,  to  prevent  cracks,  21. 
exterior,   rubble,   specifications,  821. 
facings  of  glazed  and  enamelled  bricks, 
322. 

field  rubble,  specifications,  821. 
fire  (see  fire-walls), 
foundation,  brick,  96. 

buildings    exceeding    three    stories  in 

height,  loi. 
built  against  banks,  24. 
concrete,  622. 
concrete  block,  745. 

mass,  light  buildings,  622,  623,  624. 
typical  wall  and  footing,  623. 
constructive  devices  for  damp-proofing, 
III. 

damp-proofing  of,  109. 
dampness  in,  109. 
drains  for  damp-proofing,  iii. 
general  description,  96. 
granite  block,  819. 
heavy  clay  soils,  loi. 
joints,  outside,  24.  , 
limestone,  819. 
materials,  96. 

mortar  below  and  above  grade,  97. 
outside    plastered    with    cement,  clay 

soils,  8. 
pipe-openings,  109. 
rubble,  specifications,  820. 
specifications,  819. 
stone,  96. 

superintendence  of  erection,  108. 

thickness  of,   100,  loi. 
furring,  tile,  833. 
granite,  safe  loads,  304. 
hollow,  bonding,  371. 

brick  withes,  373. 

concrete  blocks,  732,  733. 

construction,  368. 

object,  367. 

openings,  372. 

with  solid  concrete  blocks,  734. 

ventilation  of  air-spaces,  372. 
housing  together,  302. 
joining  with  slip  joints,  302. 
limestone,   safe   loads,  304. 
masonry,  dwellings,  300. 
marble,  safe  loads,  304. 
openings  in,  278. 

outside,  tile  hollow  blocks,  583,  584,  585, 
586. 

parapet  brick,  344. 
party  (see  party-walls), 
pressure  of,  on  clay  soils,  7. 


reservoir,  concrete,   reinforced,  635.  . 

retaining   (see  retaining-walls). 

rubble,  boulders  and  field  stones,  264. 
jambs,  264.  , 
method  of  building,  263.  , 
quoins,  264.  .  „, 

safe  loads,  304.  , 
specifications,  821.  '  ■  , 

stonework  for  exterior  walls,  263. 
thickness,  264^ 

window  jambs,  cut-stone,  267. 
sandstone,  safe  loads,  304. 
settlements  in  adjoining  walls,  303. 

in  joints,  100. 
slip  joints  for  joining,  302. 
spandrel   or   curtain-wall    supports,  754, 
755.    756,    757,    758.    759,    760,  761, 
762,  763,  764. 
stability  of,  87. 
stone,  angles,  99. 
bonding  of,  97. 
breaking  joint,  99. 
character  of  material,  96. 
exterior  walls,   specifications,  821. 
horizontal  joints,  97. 
least  depth  of  stone,  99. 
levelling  off,  97. 
proper  method  of  building,  99. 
safe  loads,  304. 
window  openings  in,  100. 
strength  of,  depending  on  mortar,  97. 
thickness,  concrete  blocks,  745. 

different  kinds  of  buildings,  908,  909, 
910,  911. 
tile,  hollow,  583. 
use  of  Portland  cements,  170. 
vault  (see  vault  walls), 
warped  bricks,  324. 
Wall-board  partitions  (see  partitions). 
Wall-boards,  775. 

partitions,  547. 
Wall  copings,  stone,  292. 
Wall  facing,  Pelton's  system  of  released, 
590. 

Wall-hangers,  356,  357. 
Wall-plugs, 

concrete   block   partitions,  746. 

metal,  365,  374. 
Wall  supports,  skeleton  construction,  753. 
Warehouses, 

floor-arches,  segmental,  472. 

floors,  concrete,  Roebling,  502. 

footing     widths,     calculations,  example 
with  solution,  17. 

walls,  thickness  of,  910. 
Warping, 

bricks,  312. 

arch-bricks,  324. 
Washes, 

belt-courses,  277. 
of  brick,  341. 

stone,  cutting  and  rubbing,  267. 

stone  sills,  280. 

stonework,  276. 

cut-stonework,  302. 
Water, 

effect,  on  laying  footings  on  sand  foun- 
dations, 9. 

on  foundation  bed  of  clay  and  sand 
or  gravel,  8. 

on  gravel  foundation  bed,  9. 

on  stone  footings,  107. 
in  clay  soils,  7, 
in  excavations,  24. 
in  footing  trenches,  24. 
surface,  5. 

draining  off,  rocl?  foundations,  5. 
used  to  settle  sand,  nwde  land,  founda- 


INDEX. 

W  ater  Conduits — Zeolltic  Group  of  Minerals. 


tions,  9. 
Water  conduits,  concrete,  595. 
Water-curtains,  582. 
Water-jet, 

for  drivipg  wooden  piles,  30. 

soils  best  suited  to,  30. 

spacing  piles,  36. 

uses  in  building  construction,  objection 
^  to,  30. 

sinking  corrugated  concrete  piles,  44. 
volume  and  velocity  of  water,  30. 
Water-mains,  concrete,  594. 
Water-pipes,  floors,  fire-proof,  470. 
Waterproofing, 
basements,  no. 

of  Herald  building,  N.  Y.,  in. 
brickwork,  399,  400,  401. 
filled-in  rock  fissures,  6. 
Water-proofing  stonework,  260. 
Water-resistance, 
partitions,  541. 

metal-and-plaster,  550. 
Water-soaked  soils,  foundations  on,  9. 
Wawaset  manufactured  lime-stone,  261. 
Weather, 

effect  of,  on  brickwork,  328. 
stones,  effect  on,  250. 
Weathering, 
bricks,  311. 

glazed  and  enamelled,  322. 
paving,  322. 
sand-lime,  332. 
copings,  292. 
stone  lintels,  278,  306. 
Webs,  floor  tiles,  478,  479,  480,  484. 
Weight, 

bricks,  326. 

from  wetting,  339. 
brickwork,  906. 
cement,  natural,  845,  846. 
concrete,  Portland  cement,  606. 
concrete  blocks,  740,  866. 
floor  arches,  brick,  466. 
tile,  488. 

segmental,  476. 
floors,  concrete,  flat  arch,  Roebling,  512. 
granites,  881,  883,  891. 
limestones,  881,  882,  883,  891. 
marbles,  882,  883,  891. 
partition  blocks,  plaster,  543. 

tile,  550. 
partitions,  541. 

metal-and-plaster,  552,  556. 
sandstones,  882,  883,  891. 
slates,  884. 

roofing,  244. 
stones,  881,  882,  883,  891. 
stones,  artificial,  891. 
terra-cotta,  architectural,  442. 
Welded  metal  fabric  reinforcement  (see  re- 
inforcements). 
Well-holes,  circular  stone  stairs,  294. 
Wells, 

masonry,  71. 

steel,  use  in  mud  and  silt  soils,  founda- 
tions, 10. 

West  Virginia,  Shepherdstown,  hydraulic 
cement  analysis,  145- 

Wet  clay,  danger  of,  foundations,  7. 

Wetting  bricks,  339- 

Wharves,  concrete,  595. 

White,  Canvas,  introduction  of  natural  ce- 
ments, 141. 

White  chalk,  used  in  production  of  lime, 
common,  127. 

White  coat,  plastering,  78;3. 


White   fire-proof   concrete   floor  construc- 
tion (see  floors,  fire-proof). 
White   Fire-proof   Construction   Co.,  New 
York,  clips  for  suspended  ceilings,  540. 
column  fire-proofing,  456,  457. 
floors,  fire-proof j  518. 
metal  wall  furring,  571. 
White-lead,  in  pointing  putty,  302. 
White  patent  clips  for  suspended  ceilings, 

540,  541. 
Whitewashing,  803. 

partitions,  tile,  548. 
Width  of  masonry  joints,  264. 
Wind  pressure,  importance  of  adhesive  .and 

tensile  strength  of  mortar,  196. 
Winde,  out  of,  cut-stone  surfaces,  296. 
Window  areas,  size  of,  112. 
Window  jambs,  cut-stone,  in  rubble  walls, 
267. 

Window  openings,  in  stone  walls,  100. 
Window   sills    (see  sills,  window). 

stone,  drip,  276. 
Windows, 

Gothic,  298,  299. 

partitions,  541. 

store,  stone  lintels  over,  279. 
Windsor  cement, 

neat,  790. 

dry  mortar,  790. 
Wire  cloth,  561. 

Clinton,  454,  456,  458. 
Wire  fabrics  versus  rods  and  bars  as  re- 
inforcements for  concrete  floors,  499. 
Wire-glass,  447,  582. 

windows  in  partitions,  541. 
Wire  lath  (see  lath,  wire). 

Clinton,  454,  456,  458. 

cornices  false,  841. 
Wisconsin,  natural  cements,  143. 

Milwaukee,    hydraulic    cement  analysis, 
145- 
Withes, 

brick,  385. 

hollow  walls,  373. 
Wood,  Woods  (see  also  timber). 

durability  under  water,  27. 

fire-proof,  447. 

kinds  used  for  concrete  forms,  630. 
scarcity  of,  311. 
use  for  piles,  27. 
in  brick  walls,  364. 
Wood  bricks,  364. 

Wood  buildings,  erected  in  United  States 

in  1906,  901. 
Wood     construction     (see  construction, 

wood). 
Wood  flooring,  533. 

concrete  floor  construction,  718. 
Wood  footings  (see  timber  footings). 
Wood  laths  (see  laths,  wood). 
Wood  piles  (see  piles,  wood). 
Wood  plugs,  brick  walls,  364. 
Wood  slips,  cut-stonework  joints,  300. 
Woolson,  Ira  H.,  bricks,  sand-lime,  tests, 

332. 

Working  strength  (see  strength,- working). 

Wight  &  Co.,  W.  N.,  New  York,  lock- 
woven  fabric  floor  reinforcement,  522. 

Wright,  F.  .E.,  bricks,  tests  on  sand-lime, 
330. 

Wrought-iron,  fire-resistance,  447. 
Wrought-iron  I-beams,  465,  466. 


Zeolitic   group   of   minerals,    bricks,  sand- 
lime,  331. 


4 


